index
int64
0
731k
package
stringlengths
2
98
name
stringlengths
1
76
docstring
stringlengths
0
281k
code
stringlengths
4
1.07M
signature
stringlengths
2
42.8k
38,214
pulp.apis.scip_api
parse_status
null
@staticmethod def parse_status(string: str) -> Optional[int]: for fscip_status, pulp_status in FSCIP_CMD.FSCIP_STATUSES.items(): if fscip_status in string: return pulp_status return None
(string: str) -> Optional[int]
38,215
pulp.apis.scip_api
parse_variable
null
@staticmethod def parse_variable(string: str) -> Optional[Tuple[str, float]]: fields = string.split() if len(fields) < 2: return None name, value = fields[:2] try: value = float(value) except ValueError: return None return name, value
(string: str) -> Optional[Tuple[str, float]]
38,216
pulp.apis.scip_api
readsol
Read a FSCIP solution file
@staticmethod def readsol(filename): """Read a FSCIP solution file""" with open(filename) as file: # First line must contain a solution status status_line = file.readline() status = FSCIP_CMD.parse_status(status_line) if status is None: raise PulpSolverError(f"Can't get FSCIP solver status: {status_line!r}") if status in FSCIP_CMD.NO_SOLUTION_STATUSES: return status, {} # Look for an objective value. If we can't find one, stop. objective_line = file.readline() objective = FSCIP_CMD.parse_objective(objective_line) if objective is None: raise PulpSolverError( f"Can't get FSCIP solver objective: {objective_line!r}" ) # Parse the variable values. variables: Dict[str, float] = {} for variable_line in file: variable = FSCIP_CMD.parse_variable(variable_line) if variable is None: raise PulpSolverError( f"Can't read FSCIP solver output: {variable_line!r}" ) name, value = variable variables[name] = value return status, variables
(filename)
38,247
pulp.pulp
FixedElasticSubProblem
Contains the subproblem generated by converting a fixed constraint :math:`\sum_{i}a_i x_i = b` into an elastic constraint. :param constraint: The LpConstraint that the elastic constraint is based on :param penalty: penalty applied for violation (+ve or -ve) of the constraints :param proportionFreeBound: the proportional bound (+ve and -ve) on constraint violation that is free from penalty :param proportionFreeBoundList: the proportional bound on constraint violation that is free from penalty, expressed as a list where [-ve, +ve]
class FixedElasticSubProblem(LpProblem): """ Contains the subproblem generated by converting a fixed constraint :math:`\\sum_{i}a_i x_i = b` into an elastic constraint. :param constraint: The LpConstraint that the elastic constraint is based on :param penalty: penalty applied for violation (+ve or -ve) of the constraints :param proportionFreeBound: the proportional bound (+ve and -ve) on constraint violation that is free from penalty :param proportionFreeBoundList: the proportional bound on \ constraint violation that is free from penalty, expressed as a list\ where [-ve, +ve] """ def __init__( self, constraint, penalty=None, proportionFreeBound=None, proportionFreeBoundList=None, ): subProblemName = f"{constraint.name}_elastic_SubProblem" LpProblem.__init__(self, subProblemName, const.LpMinimize) self.objective = LpAffineExpression() self.constraint = constraint self.constant = constraint.constant self.RHS = -constraint.constant self.objective = LpAffineExpression() self += constraint, "_Constraint" # create and add these variables but disabled self.freeVar = LpVariable("_free_bound", upBound=0, lowBound=0) self.upVar = LpVariable("_pos_penalty_var", upBound=0, lowBound=0) self.lowVar = LpVariable("_neg_penalty_var", upBound=0, lowBound=0) constraint.addInPlace(self.freeVar + self.lowVar + self.upVar) if proportionFreeBound: proportionFreeBoundList = [proportionFreeBound, proportionFreeBound] if proportionFreeBoundList: # add a costless variable self.freeVar.upBound = abs(constraint.constant * proportionFreeBoundList[0]) self.freeVar.lowBound = -abs( constraint.constant * proportionFreeBoundList[1] ) # Note the reversal of the upbound and lowbound due to the nature of the # variable if penalty is not None: # activate these variables self.upVar.upBound = None self.lowVar.lowBound = None self.objective = penalty * self.upVar - penalty * self.lowVar def _findValue(self, attrib): """ safe way to get the value of a variable that may not exist """ var = getattr(self, attrib, 0) if var: if value(var) is not None: return value(var) else: return 0.0 else: return 0.0 def isViolated(self): """ returns true if the penalty variables are non-zero """ upVar = self._findValue("upVar") lowVar = self._findValue("lowVar") freeVar = self._findValue("freeVar") result = abs(upVar + lowVar) >= const.EPS if result: log.debug( "isViolated %s, upVar %s, lowVar %s, freeVar %s result %s" % (self.name, upVar, lowVar, freeVar, result) ) log.debug(f"isViolated value lhs {self.findLHSValue()} constant {self.RHS}") return result def findDifferenceFromRHS(self): """ The amount the actual value varies from the RHS (sense: LHS - RHS) """ return self.findLHSValue() - self.RHS def findLHSValue(self): """ for elastic constraints finds the LHS value of the constraint without the free variable and or penalty variable assumes the constant is on the rhs """ upVar = self._findValue("upVar") lowVar = self._findValue("lowVar") freeVar = self._findValue("freeVar") return self.constraint.value() - self.constant - upVar - lowVar - freeVar def deElasticize(self): """de-elasticize constraint""" self.upVar.upBound = 0 self.lowVar.lowBound = 0 def reElasticize(self): """ Make the Subproblem elastic again after deElasticize """ self.upVar.lowBound = 0 self.upVar.upBound = None self.lowVar.upBound = 0 self.lowVar.lowBound = None def alterName(self, name): """ Alters the name of anonymous parts of the problem """ self.name = f"{name}_elastic_SubProblem" if hasattr(self, "freeVar"): self.freeVar.name = self.name + "_free_bound" if hasattr(self, "upVar"): self.upVar.name = self.name + "_pos_penalty_var" if hasattr(self, "lowVar"): self.lowVar.name = self.name + "_neg_penalty_var"
(constraint, penalty=None, proportionFreeBound=None, proportionFreeBoundList=None)
38,248
pulp.pulp
__getstate__
null
def __getstate__(self): # Remove transient data prior to pickling. state = self.__dict__.copy() del state["_variable_ids"] return state
(self)
38,249
pulp.pulp
__iadd__
null
def __iadd__(self, other): if isinstance(other, tuple): other, name = other else: name = None if other is True: return self elif other is False: raise TypeError("A False object cannot be passed as a constraint") elif isinstance(other, LpConstraintVar): self.addConstraint(other.constraint) elif isinstance(other, LpConstraint): self.addConstraint(other, name) elif isinstance(other, LpAffineExpression): if self.objective is not None: warnings.warn("Overwriting previously set objective.") self.objective = other if name is not None: # we may keep the LpAffineExpression name self.objective.name = name elif isinstance(other, LpVariable) or isinstance(other, (int, float)): if self.objective is not None: warnings.warn("Overwriting previously set objective.") self.objective = LpAffineExpression(other) self.objective.name = name else: raise TypeError( "Can only add LpConstraintVar, LpConstraint, LpAffineExpression or True objects" ) return self
(self, other)
38,250
pulp.pulp
__init__
null
def __init__( self, constraint, penalty=None, proportionFreeBound=None, proportionFreeBoundList=None, ): subProblemName = f"{constraint.name}_elastic_SubProblem" LpProblem.__init__(self, subProblemName, const.LpMinimize) self.objective = LpAffineExpression() self.constraint = constraint self.constant = constraint.constant self.RHS = -constraint.constant self.objective = LpAffineExpression() self += constraint, "_Constraint" # create and add these variables but disabled self.freeVar = LpVariable("_free_bound", upBound=0, lowBound=0) self.upVar = LpVariable("_pos_penalty_var", upBound=0, lowBound=0) self.lowVar = LpVariable("_neg_penalty_var", upBound=0, lowBound=0) constraint.addInPlace(self.freeVar + self.lowVar + self.upVar) if proportionFreeBound: proportionFreeBoundList = [proportionFreeBound, proportionFreeBound] if proportionFreeBoundList: # add a costless variable self.freeVar.upBound = abs(constraint.constant * proportionFreeBoundList[0]) self.freeVar.lowBound = -abs( constraint.constant * proportionFreeBoundList[1] ) # Note the reversal of the upbound and lowbound due to the nature of the # variable if penalty is not None: # activate these variables self.upVar.upBound = None self.lowVar.lowBound = None self.objective = penalty * self.upVar - penalty * self.lowVar
(self, constraint, penalty=None, proportionFreeBound=None, proportionFreeBoundList=None)
38,251
pulp.pulp
__repr__
null
def __repr__(self): s = self.name + ":\n" if self.sense == 1: s += "MINIMIZE\n" else: s += "MAXIMIZE\n" s += repr(self.objective) + "\n" if self.constraints: s += "SUBJECT TO\n" for n, c in self.constraints.items(): s += c.asCplexLpConstraint(n) + "\n" s += "VARIABLES\n" for v in self.variables(): s += v.asCplexLpVariable() + " " + const.LpCategories[v.cat] + "\n" return s
(self)
38,252
pulp.pulp
__setstate__
null
def __setstate__(self, state): # Update transient data prior to unpickling. self.__dict__.update(state) self._variable_ids = {} for v in self._variables: self._variable_ids[v.hash] = v
(self, state)
38,253
pulp.pulp
_findValue
safe way to get the value of a variable that may not exist
def _findValue(self, attrib): """ safe way to get the value of a variable that may not exist """ var = getattr(self, attrib, 0) if var: if value(var) is not None: return value(var) else: return 0.0 else: return 0.0
(self, attrib)
38,254
pulp.pulp
add
null
def add(self, constraint, name=None): self.addConstraint(constraint, name)
(self, constraint, name=None)
38,255
pulp.pulp
addConstraint
null
def addConstraint(self, constraint, name=None): if not isinstance(constraint, LpConstraint): raise TypeError("Can only add LpConstraint objects") if name: constraint.name = name try: if constraint.name: name = constraint.name else: name = self.unusedConstraintName() except AttributeError: raise TypeError("Can only add LpConstraint objects") # removed as this test fails for empty constraints # if len(constraint) == 0: # if not constraint.valid(): # raise ValueError, "Cannot add false constraints" if name in self.constraints: if self.noOverlap: raise const.PulpError("overlapping constraint names: " + name) else: print("Warning: overlapping constraint names:", name) self.constraints[name] = constraint self.modifiedConstraints.append(constraint) self.addVariables(list(constraint.keys()))
(self, constraint, name=None)
38,256
pulp.pulp
addVariable
Adds a variable to the problem before a constraint is added @param variable: the variable to be added
def addVariable(self, variable): """ Adds a variable to the problem before a constraint is added @param variable: the variable to be added """ if variable.hash not in self._variable_ids: self._variables.append(variable) self._variable_ids[variable.hash] = variable
(self, variable)
38,257
pulp.pulp
addVariables
Adds variables to the problem before a constraint is added @param variables: the variables to be added
def addVariables(self, variables): """ Adds variables to the problem before a constraint is added @param variables: the variables to be added """ for v in variables: self.addVariable(v)
(self, variables)
38,258
pulp.pulp
alterName
Alters the name of anonymous parts of the problem
def alterName(self, name): """ Alters the name of anonymous parts of the problem """ self.name = f"{name}_elastic_SubProblem" if hasattr(self, "freeVar"): self.freeVar.name = self.name + "_free_bound" if hasattr(self, "upVar"): self.upVar.name = self.name + "_pos_penalty_var" if hasattr(self, "lowVar"): self.lowVar.name = self.name + "_neg_penalty_var"
(self, name)
38,259
pulp.pulp
assignConsPi
null
def assignConsPi(self, values): for name in values: try: self.constraints[name].pi = values[name] except KeyError: pass
(self, values)
38,260
pulp.pulp
assignConsSlack
null
def assignConsSlack(self, values, activity=False): for name in values: try: if activity: # reports the activity not the slack self.constraints[name].slack = -1 * ( self.constraints[name].constant + float(values[name]) ) else: self.constraints[name].slack = float(values[name]) except KeyError: pass
(self, values, activity=False)
38,261
pulp.pulp
assignStatus
Sets the status of the model after solving. :param status: code for the status of the model :param sol_status: code for the status of the solution :return:
def assignStatus(self, status, sol_status=None): """ Sets the status of the model after solving. :param status: code for the status of the model :param sol_status: code for the status of the solution :return: """ if status not in const.LpStatus: raise const.PulpError("Invalid status code: " + str(status)) if sol_status is not None and sol_status not in const.LpSolution: raise const.PulpError("Invalid solution status code: " + str(sol_status)) self.status = status if sol_status is None: sol_status = const.LpStatusToSolution.get( status, const.LpSolutionNoSolutionFound ) self.sol_status = sol_status return True
(self, status, sol_status=None)
38,262
pulp.pulp
assignVarsDj
null
def assignVarsDj(self, values): variables = self.variablesDict() for name in values: if name != "__dummy": variables[name].dj = values[name]
(self, values)
38,263
pulp.pulp
assignVarsVals
null
def assignVarsVals(self, values): variables = self.variablesDict() for name in values: if name != "__dummy": variables[name].varValue = values[name]
(self, values)
38,264
pulp.pulp
checkDuplicateVars
Checks if there are at least two variables with the same name :return: 1 :raises `const.PulpError`: if there ar duplicates
def checkDuplicateVars(self) -> None: """ Checks if there are at least two variables with the same name :return: 1 :raises `const.PulpError`: if there ar duplicates """ name_counter = Counter(variable.name for variable in self.variables()) repeated_names = { (name, count) for name, count in name_counter.items() if count >= 2 } if repeated_names: raise const.PulpError(f"Repeated variable names: {repeated_names}")
(self) -> NoneType
38,265
pulp.pulp
checkLengthVars
Checks if variables have names smaller than `max_length` :param int max_length: max size for variable name :return: :raises const.PulpError: if there is at least one variable that has a long name
def checkLengthVars(self, max_length: int) -> None: """ Checks if variables have names smaller than `max_length` :param int max_length: max size for variable name :return: :raises const.PulpError: if there is at least one variable that has a long name """ long_names = [ variable.name for variable in self.variables() if len(variable.name) > max_length ] if long_names: raise const.PulpError( f"Variable names too long for Lp format: {long_names}" )
(self, max_length: int) -> NoneType
38,266
pulp.pulp
coefficients
null
def coefficients(self, translation=None): coefs = [] if translation == None: for c in self.constraints: cst = self.constraints[c] coefs.extend([(v.name, c, cst[v]) for v in cst]) else: for c in self.constraints: ctr = translation[c] cst = self.constraints[c] coefs.extend([(translation[v.name], ctr, cst[v]) for v in cst]) return coefs
(self, translation=None)
38,267
pulp.pulp
copy
Make a copy of self. Expressions are copied by reference
def copy(self): """Make a copy of self. Expressions are copied by reference""" lpcopy = LpProblem(name=self.name, sense=self.sense) lpcopy.objective = self.objective lpcopy.constraints = self.constraints.copy() lpcopy.sos1 = self.sos1.copy() lpcopy.sos2 = self.sos2.copy() return lpcopy
(self)
38,268
pulp.pulp
deElasticize
de-elasticize constraint
def deElasticize(self): """de-elasticize constraint""" self.upVar.upBound = 0 self.lowVar.lowBound = 0
(self)
38,269
pulp.pulp
deepcopy
Make a copy of self. Expressions are copied by value
def deepcopy(self): """Make a copy of self. Expressions are copied by value""" lpcopy = LpProblem(name=self.name, sense=self.sense) if self.objective is not None: lpcopy.objective = self.objective.copy() lpcopy.constraints = {} for k, v in self.constraints.items(): lpcopy.constraints[k] = v.copy() lpcopy.sos1 = self.sos1.copy() lpcopy.sos2 = self.sos2.copy() return lpcopy
(self)
38,270
pulp.pulp
extend
extends an LpProblem by adding constraints either from a dictionary a tuple or another LpProblem object. @param use_objective: determines whether the objective is imported from the other problem For dictionaries the constraints will be named with the keys For tuples an unique name will be generated For LpProblems the name of the problem will be added to the constraints name
def extend(self, other, use_objective=True): """ extends an LpProblem by adding constraints either from a dictionary a tuple or another LpProblem object. @param use_objective: determines whether the objective is imported from the other problem For dictionaries the constraints will be named with the keys For tuples an unique name will be generated For LpProblems the name of the problem will be added to the constraints name """ if isinstance(other, dict): for name in other: self.constraints[name] = other[name] elif isinstance(other, LpProblem): for v in set(other.variables()).difference(self.variables()): v.name = other.name + v.name for name, c in other.constraints.items(): c.name = other.name + name self.addConstraint(c) if use_objective: self.objective += other.objective else: for c in other: if isinstance(c, tuple): name = c[0] c = c[1] else: name = None if not name: name = c.name if not name: name = self.unusedConstraintName() self.constraints[name] = c
(self, other, use_objective=True)
38,271
pulp.pulp
findDifferenceFromRHS
The amount the actual value varies from the RHS (sense: LHS - RHS)
def findDifferenceFromRHS(self): """ The amount the actual value varies from the RHS (sense: LHS - RHS) """ return self.findLHSValue() - self.RHS
(self)
38,272
pulp.pulp
findLHSValue
for elastic constraints finds the LHS value of the constraint without the free variable and or penalty variable assumes the constant is on the rhs
def findLHSValue(self): """ for elastic constraints finds the LHS value of the constraint without the free variable and or penalty variable assumes the constant is on the rhs """ upVar = self._findValue("upVar") lowVar = self._findValue("lowVar") freeVar = self._findValue("freeVar") return self.constraint.value() - self.constant - upVar - lowVar - freeVar
(self)
38,273
pulp.pulp
fixObjective
null
def fixObjective(self): if self.objective is None: self.objective = 0 wasNone = 1 else: wasNone = 0 if not isinstance(self.objective, LpAffineExpression): self.objective = LpAffineExpression(self.objective) if self.objective.isNumericalConstant(): dummyVar = self.get_dummyVar() self.objective += dummyVar else: dummyVar = None return wasNone, dummyVar
(self)
38,274
pulp.pulp
getSense
null
def getSense(self): return self.sense
(self)
38,275
pulp.pulp
get_dummyVar
null
def get_dummyVar(self): if self.dummyVar is None: self.dummyVar = LpVariable("__dummy", 0, 0) return self.dummyVar
(self)
38,276
pulp.pulp
infeasibilityGap
null
def infeasibilityGap(self, mip=1): gap = 0 for v in self.variables(): gap = max(abs(v.infeasibilityGap(mip)), gap) for c in self.constraints.values(): if not c.valid(0): gap = max(abs(c.value()), gap) return gap
(self, mip=1)
38,277
pulp.pulp
isMIP
null
def isMIP(self): for v in self.variables(): if v.cat == const.LpInteger: return 1 return 0
(self)
38,278
pulp.pulp
isViolated
returns true if the penalty variables are non-zero
def isViolated(self): """ returns true if the penalty variables are non-zero """ upVar = self._findValue("upVar") lowVar = self._findValue("lowVar") freeVar = self._findValue("freeVar") result = abs(upVar + lowVar) >= const.EPS if result: log.debug( "isViolated %s, upVar %s, lowVar %s, freeVar %s result %s" % (self.name, upVar, lowVar, freeVar, result) ) log.debug(f"isViolated value lhs {self.findLHSValue()} constant {self.RHS}") return result
(self)
38,279
pulp.pulp
normalisedNames
null
def normalisedNames(self): constraintsNames = {k: "C%07d" % i for i, k in enumerate(self.constraints)} _variables = self.variables() variablesNames = {k.name: "X%07d" % i for i, k in enumerate(_variables)} return constraintsNames, variablesNames, "OBJ"
(self)
38,280
pulp.pulp
numConstraints
:return: number of constraints in model
def numConstraints(self): """ :return: number of constraints in model """ return len(self.constraints)
(self)
38,281
pulp.pulp
numVariables
:return: number of variables in model
def numVariables(self): """ :return: number of variables in model """ return len(self._variable_ids)
(self)
38,282
pulp.pulp
reElasticize
Make the Subproblem elastic again after deElasticize
def reElasticize(self): """ Make the Subproblem elastic again after deElasticize """ self.upVar.lowBound = 0 self.upVar.upBound = None self.lowVar.upBound = 0 self.lowVar.lowBound = None
(self)
38,283
pulp.pulp
resolve
resolves an Problem using the same solver as previously
def resolve(self, solver=None, **kwargs): """ resolves an Problem using the same solver as previously """ if not (solver): solver = self.solver if self.resolveOK: return self.solver.actualResolve(self, **kwargs) else: return self.solve(solver=solver, **kwargs)
(self, solver=None, **kwargs)
38,284
pulp.pulp
restoreObjective
null
def restoreObjective(self, wasNone, dummyVar): if wasNone: self.objective = None elif not dummyVar is None: self.objective -= dummyVar
(self, wasNone, dummyVar)
38,285
pulp.pulp
roundSolution
Rounds the lp variables Inputs: - none Side Effects: - The lp variables are rounded
def roundSolution(self, epsInt=1e-5, eps=1e-7): """ Rounds the lp variables Inputs: - none Side Effects: - The lp variables are rounded """ for v in self.variables(): v.round(epsInt, eps)
(self, epsInt=1e-05, eps=1e-07)
38,286
pulp.pulp
sequentialSolve
Solve the given Lp problem with several objective functions. This function sequentially changes the objective of the problem and then adds the objective function as a constraint :param objectives: the list of objectives to be used to solve the problem :param absoluteTols: the list of absolute tolerances to be applied to the constraints should be +ve for a minimise objective :param relativeTols: the list of relative tolerances applied to the constraints :param solver: the specific solver to be used, defaults to the default solver.
def sequentialSolve( self, objectives, absoluteTols=None, relativeTols=None, solver=None, debug=False ): """ Solve the given Lp problem with several objective functions. This function sequentially changes the objective of the problem and then adds the objective function as a constraint :param objectives: the list of objectives to be used to solve the problem :param absoluteTols: the list of absolute tolerances to be applied to the constraints should be +ve for a minimise objective :param relativeTols: the list of relative tolerances applied to the constraints :param solver: the specific solver to be used, defaults to the default solver. """ # TODO Add a penalty variable to make problems elastic # TODO add the ability to accept different status values i.e. infeasible etc if not (solver): solver = self.solver if not (solver): solver = LpSolverDefault if not (absoluteTols): absoluteTols = [0] * len(objectives) if not (relativeTols): relativeTols = [1] * len(objectives) # time it self.startClock() statuses = [] for i, (obj, absol, rel) in enumerate( zip(objectives, absoluteTols, relativeTols) ): self.setObjective(obj) status = solver.actualSolve(self) statuses.append(status) if debug: self.writeLP(f"{i}Sequence.lp") if self.sense == const.LpMinimize: self += obj <= value(obj) * rel + absol, f"Sequence_Objective_{i}" elif self.sense == const.LpMaximize: self += obj >= value(obj) * rel + absol, f"Sequence_Objective_{i}" self.stopClock() self.solver = solver return statuses
(self, objectives, absoluteTols=None, relativeTols=None, solver=None, debug=False)
38,287
pulp.pulp
setObjective
Sets the input variable as the objective function. Used in Columnwise Modelling :param obj: the objective function of type :class:`LpConstraintVar` Side Effects: - The objective function is set
def setObjective(self, obj): """ Sets the input variable as the objective function. Used in Columnwise Modelling :param obj: the objective function of type :class:`LpConstraintVar` Side Effects: - The objective function is set """ if isinstance(obj, LpVariable): # allows the user to add a LpVariable as an objective obj = obj + 0.0 try: obj = obj.constraint name = obj.name except AttributeError: name = None self.objective = obj self.objective.name = name self.resolveOK = False
(self, obj)
38,288
pulp.pulp
setSolver
Sets the Solver for this problem useful if you are using resolve
def setSolver(self, solver=LpSolverDefault): """Sets the Solver for this problem useful if you are using resolve """ self.solver = solver
(self, solver=<pulp.apis.coin_api.PULP_CBC_CMD object at 0x7fae47fd56f0>)
38,289
pulp.pulp
solve
Solve the given Lp problem. This function changes the problem to make it suitable for solving then calls the solver.actualSolve() method to find the solution :param solver: Optional: the specific solver to be used, defaults to the default solver. Side Effects: - The attributes of the problem object are changed in :meth:`~pulp.solver.LpSolver.actualSolve()` to reflect the Lp solution
def solve(self, solver=None, **kwargs): """ Solve the given Lp problem. This function changes the problem to make it suitable for solving then calls the solver.actualSolve() method to find the solution :param solver: Optional: the specific solver to be used, defaults to the default solver. Side Effects: - The attributes of the problem object are changed in :meth:`~pulp.solver.LpSolver.actualSolve()` to reflect the Lp solution """ if not (solver): solver = self.solver if not (solver): solver = LpSolverDefault wasNone, dummyVar = self.fixObjective() # time it self.startClock() status = solver.actualSolve(self, **kwargs) self.stopClock() self.restoreObjective(wasNone, dummyVar) self.solver = solver return status
(self, solver=None, **kwargs)
38,290
pulp.pulp
startClock
initializes properties with the current time
def startClock(self): "initializes properties with the current time" self.solutionCpuTime = -clock() self.solutionTime = -time()
(self)
38,291
pulp.pulp
stopClock
updates time wall time and cpu time
def stopClock(self): "updates time wall time and cpu time" self.solutionTime += time() self.solutionCpuTime += clock()
(self)
38,292
pulp.pulp
toDict
creates a dictionary from the model with as much data as possible. It replaces variables by variable names. So it requires to have unique names for variables. :return: dictionary with model data :rtype: dict
def toDict(self): """ creates a dictionary from the model with as much data as possible. It replaces variables by variable names. So it requires to have unique names for variables. :return: dictionary with model data :rtype: dict """ try: self.checkDuplicateVars() except const.PulpError: raise const.PulpError( "Duplicated names found in variables:\nto export the model, variable names need to be unique" ) self.fixObjective() variables = self.variables() return dict( objective=dict( name=self.objective.name, coefficients=self.objective.toDict() ), constraints=[v.toDict() for v in self.constraints.values()], variables=[v.toDict() for v in variables], parameters=dict( name=self.name, sense=self.sense, status=self.status, sol_status=self.sol_status, ), sos1=list(self.sos1.values()), sos2=list(self.sos2.values()), )
(self)
38,293
pulp.pulp
toJson
Creates a json file from the LpProblem information :param str filename: filename to write json :param args: additional arguments for json function :param kwargs: additional keyword arguments for json function :return: None
def toJson(self, filename, *args, **kwargs): """ Creates a json file from the LpProblem information :param str filename: filename to write json :param args: additional arguments for json function :param kwargs: additional keyword arguments for json function :return: None """ with open(filename, "w") as f: json.dump(self.toDict(), f, *args, **kwargs)
(self, filename, *args, **kwargs)
38,296
pulp.pulp
unusedConstraintName
null
def unusedConstraintName(self): self.lastUnused += 1 while 1: s = "_C%d" % self.lastUnused if s not in self.constraints: break self.lastUnused += 1 return s
(self)
38,297
pulp.pulp
valid
null
def valid(self, eps=0): for v in self.variables(): if not v.valid(eps): return False for c in self.constraints.values(): if not c.valid(eps): return False else: return True
(self, eps=0)
38,298
pulp.pulp
variables
Returns the problem variables :return: A list containing the problem variables :rtype: (list, :py:class:`LpVariable`)
def variables(self): """ Returns the problem variables :return: A list containing the problem variables :rtype: (list, :py:class:`LpVariable`) """ if self.objective: self.addVariables(list(self.objective.keys())) for c in self.constraints.values(): self.addVariables(list(c.keys())) self._variables.sort(key=lambda v: v.name) return self._variables
(self)
38,299
pulp.pulp
variablesDict
null
def variablesDict(self): variables = {} if self.objective: for v in self.objective: variables[v.name] = v for c in list(self.constraints.values()): for v in c: variables[v.name] = v return variables
(self)
38,300
pulp.pulp
writeLP
Write the given Lp problem to a .lp file. This function writes the specifications (objective function, constraints, variables) of the defined Lp problem to a file. :param str filename: the name of the file to be created. :return: variables Side Effects: - The file is created
def writeLP(self, filename, writeSOS=1, mip=1, max_length=100): """ Write the given Lp problem to a .lp file. This function writes the specifications (objective function, constraints, variables) of the defined Lp problem to a file. :param str filename: the name of the file to be created. :return: variables Side Effects: - The file is created """ return mpslp.writeLP( self, filename=filename, writeSOS=writeSOS, mip=mip, max_length=max_length )
(self, filename, writeSOS=1, mip=1, max_length=100)
38,301
pulp.pulp
writeMPS
Writes an mps files from the problem information :param str filename: name of the file to write :param int mpsSense: :param bool rename: if True, normalized names are used for variables and constraints :param mip: variables and variable renames :return: Side Effects: - The file is created
def writeMPS( self, filename, mpsSense=0, rename=0, mip=1, with_objsense: bool = False ): """ Writes an mps files from the problem information :param str filename: name of the file to write :param int mpsSense: :param bool rename: if True, normalized names are used for variables and constraints :param mip: variables and variable renames :return: Side Effects: - The file is created """ return mpslp.writeMPS( self, filename, mpsSense=mpsSense, rename=rename, mip=mip, with_objsense=with_objsense, )
(self, filename, mpsSense=0, rename=0, mip=1, with_objsense: bool = False)
38,302
pulp.pulp
FractionElasticSubProblem
Contains the subproblem generated by converting a Fraction constraint numerator/(numerator+complement) = b into an elastic constraint :param name: The name of the elastic subproblem :param penalty: penalty applied for violation (+ve or -ve) of the constraints :param proportionFreeBound: the proportional bound (+ve and -ve) on constraint violation that is free from penalty :param proportionFreeBoundList: the proportional bound on constraint violation that is free from penalty, expressed as a list where [-ve, +ve]
class FractionElasticSubProblem(FixedElasticSubProblem): """ Contains the subproblem generated by converting a Fraction constraint numerator/(numerator+complement) = b into an elastic constraint :param name: The name of the elastic subproblem :param penalty: penalty applied for violation (+ve or -ve) of the constraints :param proportionFreeBound: the proportional bound (+ve and -ve) on constraint violation that is free from penalty :param proportionFreeBoundList: the proportional bound on constraint violation that is free from penalty, expressed as a list where [-ve, +ve] """ def __init__( self, name, numerator, RHS, sense, complement=None, denominator=None, penalty=None, proportionFreeBound=None, proportionFreeBoundList=None, ): subProblemName = f"{name}_elastic_SubProblem" self.numerator = numerator if denominator is None and complement is not None: self.complement = complement self.denominator = numerator + complement elif denominator is not None and complement is None: self.denominator = denominator self.complement = denominator - numerator else: raise const.PulpError( "only one of denominator and complement must be specified" ) self.RHS = RHS self.lowTarget = self.upTarget = None LpProblem.__init__(self, subProblemName, const.LpMinimize) self.freeVar = LpVariable("_free_bound", upBound=0, lowBound=0) self.upVar = LpVariable("_pos_penalty_var", upBound=0, lowBound=0) self.lowVar = LpVariable("_neg_penalty_var", upBound=0, lowBound=0) if proportionFreeBound: proportionFreeBoundList = [proportionFreeBound, proportionFreeBound] if proportionFreeBoundList: upProportionFreeBound, lowProportionFreeBound = proportionFreeBoundList else: upProportionFreeBound, lowProportionFreeBound = (0, 0) # create an objective self += LpAffineExpression() # There are three cases if the constraint.sense is ==, <=, >= if sense in [const.LpConstraintEQ, const.LpConstraintLE]: # create a constraint the sets the upper bound of target self.upTarget = RHS + upProportionFreeBound self.upConstraint = LpFractionConstraint( self.numerator, self.complement, const.LpConstraintLE, self.upTarget, denominator=self.denominator, ) if penalty is not None: self.lowVar.lowBound = None self.objective += -1 * penalty * self.lowVar self.upConstraint += self.lowVar self += self.upConstraint, "_upper_constraint" if sense in [const.LpConstraintEQ, const.LpConstraintGE]: # create a constraint the sets the lower bound of target self.lowTarget = RHS - lowProportionFreeBound self.lowConstraint = LpFractionConstraint( self.numerator, self.complement, const.LpConstraintGE, self.lowTarget, denominator=self.denominator, ) if penalty is not None: self.upVar.upBound = None self.objective += penalty * self.upVar self.lowConstraint += self.upVar self += self.lowConstraint, "_lower_constraint" def findLHSValue(self): """ for elastic constraints finds the LHS value of the constraint without the free variable and or penalty variable assumes the constant is on the rhs """ # uses code from LpFractionConstraint if abs(value(self.denominator)) >= const.EPS: return value(self.numerator) / value(self.denominator) else: if abs(value(self.numerator)) <= const.EPS: # zero divided by zero will return 1 return 1.0 else: raise ZeroDivisionError def isViolated(self): """ returns true if the penalty variables are non-zero """ if abs(value(self.denominator)) >= const.EPS: if self.lowTarget is not None: if self.lowTarget > self.findLHSValue(): return True if self.upTarget is not None: if self.findLHSValue() > self.upTarget: return True else: # if the denominator is zero the constraint is satisfied return False
(name, numerator, RHS, sense, complement=None, denominator=None, penalty=None, proportionFreeBound=None, proportionFreeBoundList=None)
38,305
pulp.pulp
__init__
null
def __init__( self, name, numerator, RHS, sense, complement=None, denominator=None, penalty=None, proportionFreeBound=None, proportionFreeBoundList=None, ): subProblemName = f"{name}_elastic_SubProblem" self.numerator = numerator if denominator is None and complement is not None: self.complement = complement self.denominator = numerator + complement elif denominator is not None and complement is None: self.denominator = denominator self.complement = denominator - numerator else: raise const.PulpError( "only one of denominator and complement must be specified" ) self.RHS = RHS self.lowTarget = self.upTarget = None LpProblem.__init__(self, subProblemName, const.LpMinimize) self.freeVar = LpVariable("_free_bound", upBound=0, lowBound=0) self.upVar = LpVariable("_pos_penalty_var", upBound=0, lowBound=0) self.lowVar = LpVariable("_neg_penalty_var", upBound=0, lowBound=0) if proportionFreeBound: proportionFreeBoundList = [proportionFreeBound, proportionFreeBound] if proportionFreeBoundList: upProportionFreeBound, lowProportionFreeBound = proportionFreeBoundList else: upProportionFreeBound, lowProportionFreeBound = (0, 0) # create an objective self += LpAffineExpression() # There are three cases if the constraint.sense is ==, <=, >= if sense in [const.LpConstraintEQ, const.LpConstraintLE]: # create a constraint the sets the upper bound of target self.upTarget = RHS + upProportionFreeBound self.upConstraint = LpFractionConstraint( self.numerator, self.complement, const.LpConstraintLE, self.upTarget, denominator=self.denominator, ) if penalty is not None: self.lowVar.lowBound = None self.objective += -1 * penalty * self.lowVar self.upConstraint += self.lowVar self += self.upConstraint, "_upper_constraint" if sense in [const.LpConstraintEQ, const.LpConstraintGE]: # create a constraint the sets the lower bound of target self.lowTarget = RHS - lowProportionFreeBound self.lowConstraint = LpFractionConstraint( self.numerator, self.complement, const.LpConstraintGE, self.lowTarget, denominator=self.denominator, ) if penalty is not None: self.upVar.upBound = None self.objective += penalty * self.upVar self.lowConstraint += self.upVar self += self.lowConstraint, "_lower_constraint"
(self, name, numerator, RHS, sense, complement=None, denominator=None, penalty=None, proportionFreeBound=None, proportionFreeBoundList=None)
38,327
pulp.pulp
findLHSValue
for elastic constraints finds the LHS value of the constraint without the free variable and or penalty variable assumes the constant is on the rhs
def findLHSValue(self): """ for elastic constraints finds the LHS value of the constraint without the free variable and or penalty variable assumes the constant is on the rhs """ # uses code from LpFractionConstraint if abs(value(self.denominator)) >= const.EPS: return value(self.numerator) / value(self.denominator) else: if abs(value(self.numerator)) <= const.EPS: # zero divided by zero will return 1 return 1.0 else: raise ZeroDivisionError
(self)
38,333
pulp.pulp
isViolated
returns true if the penalty variables are non-zero
def isViolated(self): """ returns true if the penalty variables are non-zero """ if abs(value(self.denominator)) >= const.EPS: if self.lowTarget is not None: if self.lowTarget > self.findLHSValue(): return True if self.upTarget is not None: if self.findLHSValue() > self.upTarget: return True else: # if the denominator is zero the constraint is satisfied return False
(self)
38,357
pulp.apis.glpk_api
GLPK_CMD
The GLPK LP solver
class GLPK_CMD(LpSolver_CMD): """The GLPK LP solver""" name = "GLPK_CMD" def __init__( self, path=None, keepFiles=False, mip=True, msg=True, options=None, timeLimit=None, ): """ :param bool mip: if False, assume LP even if integer variables :param bool msg: if False, no log is shown :param float timeLimit: maximum time for solver (in seconds) :param list options: list of additional options to pass to solver :param bool keepFiles: if True, files are saved in the current directory and not deleted after solving :param str path: path to the solver binary """ LpSolver_CMD.__init__( self, mip=mip, msg=msg, timeLimit=timeLimit, options=options, path=path, keepFiles=keepFiles, ) def defaultPath(self): return self.executableExtension(glpk_path) def available(self): """True if the solver is available""" return self.executable(self.path) def actualSolve(self, lp): """Solve a well formulated lp problem""" if not self.executable(self.path): raise PulpSolverError("PuLP: cannot execute " + self.path) tmpLp, tmpSol = self.create_tmp_files(lp.name, "lp", "sol") lp.writeLP(tmpLp, writeSOS=0) proc = ["glpsol", "--cpxlp", tmpLp, "-o", tmpSol] if self.timeLimit: proc.extend(["--tmlim", str(self.timeLimit)]) if not self.mip: proc.append("--nomip") proc.extend(self.options) self.solution_time = clock() if not self.msg: proc[0] = self.path pipe = open(os.devnull, "w") if operating_system == "win": # Prevent flashing windows if used from a GUI application startupinfo = subprocess.STARTUPINFO() startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW rc = subprocess.call( proc, stdout=pipe, stderr=pipe, startupinfo=startupinfo ) else: rc = subprocess.call(proc, stdout=pipe, stderr=pipe) if rc: raise PulpSolverError( "PuLP: Error while trying to execute " + self.path ) pipe.close() else: if os.name != "nt": rc = os.spawnvp(os.P_WAIT, self.path, proc) else: rc = os.spawnv(os.P_WAIT, self.executable(self.path), proc) if rc == 127: raise PulpSolverError( "PuLP: Error while trying to execute " + self.path ) self.solution_time += clock() if not os.path.exists(tmpSol): raise PulpSolverError("PuLP: Error while executing " + self.path) status, values = self.readsol(tmpSol) lp.assignVarsVals(values) lp.assignStatus(status) self.delete_tmp_files(tmpLp, tmpSol) return status def readsol(self, filename): """Read a GLPK solution file""" with open(filename) as f: f.readline() rows = int(f.readline().split()[1]) cols = int(f.readline().split()[1]) f.readline() statusString = f.readline()[12:-1] glpkStatus = { "INTEGER OPTIMAL": constants.LpStatusOptimal, "INTEGER NON-OPTIMAL": constants.LpStatusOptimal, "OPTIMAL": constants.LpStatusOptimal, "INFEASIBLE (FINAL)": constants.LpStatusInfeasible, "INTEGER UNDEFINED": constants.LpStatusUndefined, "UNBOUNDED": constants.LpStatusUnbounded, "UNDEFINED": constants.LpStatusUndefined, "INTEGER EMPTY": constants.LpStatusInfeasible, } if statusString not in glpkStatus: raise PulpSolverError("Unknown status returned by GLPK") status = glpkStatus[statusString] isInteger = statusString in [ "INTEGER NON-OPTIMAL", "INTEGER OPTIMAL", "INTEGER UNDEFINED", "INTEGER EMPTY", ] values = {} for i in range(4): f.readline() for i in range(rows): line = f.readline().split() if len(line) == 2: f.readline() for i in range(3): f.readline() for i in range(cols): line = f.readline().split() name = line[1] if len(line) == 2: line = [0, 0] + f.readline().split() if isInteger: if line[2] == "*": value = int(float(line[3])) else: value = float(line[2]) else: value = float(line[3]) values[name] = value return status, values
(path=None, keepFiles=False, mip=True, msg=True, options=None, timeLimit=None)
38,360
pulp.apis.glpk_api
actualSolve
Solve a well formulated lp problem
def actualSolve(self, lp): """Solve a well formulated lp problem""" if not self.executable(self.path): raise PulpSolverError("PuLP: cannot execute " + self.path) tmpLp, tmpSol = self.create_tmp_files(lp.name, "lp", "sol") lp.writeLP(tmpLp, writeSOS=0) proc = ["glpsol", "--cpxlp", tmpLp, "-o", tmpSol] if self.timeLimit: proc.extend(["--tmlim", str(self.timeLimit)]) if not self.mip: proc.append("--nomip") proc.extend(self.options) self.solution_time = clock() if not self.msg: proc[0] = self.path pipe = open(os.devnull, "w") if operating_system == "win": # Prevent flashing windows if used from a GUI application startupinfo = subprocess.STARTUPINFO() startupinfo.dwFlags |= subprocess.STARTF_USESHOWWINDOW rc = subprocess.call( proc, stdout=pipe, stderr=pipe, startupinfo=startupinfo ) else: rc = subprocess.call(proc, stdout=pipe, stderr=pipe) if rc: raise PulpSolverError( "PuLP: Error while trying to execute " + self.path ) pipe.close() else: if os.name != "nt": rc = os.spawnvp(os.P_WAIT, self.path, proc) else: rc = os.spawnv(os.P_WAIT, self.executable(self.path), proc) if rc == 127: raise PulpSolverError( "PuLP: Error while trying to execute " + self.path ) self.solution_time += clock() if not os.path.exists(tmpSol): raise PulpSolverError("PuLP: Error while executing " + self.path) status, values = self.readsol(tmpSol) lp.assignVarsVals(values) lp.assignStatus(status) self.delete_tmp_files(tmpLp, tmpSol) return status
(self, lp)
38,364
pulp.apis.glpk_api
defaultPath
null
def defaultPath(self): return self.executableExtension(glpk_path)
(self)
38,369
pulp.apis.glpk_api
readsol
Read a GLPK solution file
def readsol(self, filename): """Read a GLPK solution file""" with open(filename) as f: f.readline() rows = int(f.readline().split()[1]) cols = int(f.readline().split()[1]) f.readline() statusString = f.readline()[12:-1] glpkStatus = { "INTEGER OPTIMAL": constants.LpStatusOptimal, "INTEGER NON-OPTIMAL": constants.LpStatusOptimal, "OPTIMAL": constants.LpStatusOptimal, "INFEASIBLE (FINAL)": constants.LpStatusInfeasible, "INTEGER UNDEFINED": constants.LpStatusUndefined, "UNBOUNDED": constants.LpStatusUnbounded, "UNDEFINED": constants.LpStatusUndefined, "INTEGER EMPTY": constants.LpStatusInfeasible, } if statusString not in glpkStatus: raise PulpSolverError("Unknown status returned by GLPK") status = glpkStatus[statusString] isInteger = statusString in [ "INTEGER NON-OPTIMAL", "INTEGER OPTIMAL", "INTEGER UNDEFINED", "INTEGER EMPTY", ] values = {} for i in range(4): f.readline() for i in range(rows): line = f.readline().split() if len(line) == 2: f.readline() for i in range(3): f.readline() for i in range(cols): line = f.readline().split() name = line[1] if len(line) == 2: line = [0, 0] + f.readline().split() if isInteger: if line[2] == "*": value = int(float(line[3])) else: value = float(line[2]) else: value = float(line[3]) values[name] = value return status, values
(self, filename)
38,397
pulp.apis.gurobi_api
GUROBI
The Gurobi LP/MIP solver (via its python interface) The Gurobi variables are available (after a solve) in var.solverVar Constraints in constraint.solverConstraint and the Model is in prob.solverModel
class GUROBI(LpSolver): """ The Gurobi LP/MIP solver (via its python interface) The Gurobi variables are available (after a solve) in var.solverVar Constraints in constraint.solverConstraint and the Model is in prob.solverModel """ name = "GUROBI" env = None try: sys.path.append(gurobi_path) # to import the name into the module scope global gp import gurobipy as gp except: # FIXME: Bug because gurobi returns # a gurobi exception on failed imports def available(self): """True if the solver is available""" return False def actualSolve(self, lp, callback=None): """Solve a well formulated lp problem""" raise PulpSolverError("GUROBI: Not Available") else: def __init__( self, mip=True, msg=True, timeLimit=None, gapRel=None, warmStart=False, logPath=None, env=None, envOptions=None, manageEnv=False, **solverParams, ): """ :param bool mip: if False, assume LP even if integer variables :param bool msg: if False, no log is shown :param float timeLimit: maximum time for solver (in seconds) :param float gapRel: relative gap tolerance for the solver to stop (in fraction) :param bool warmStart: if True, the solver will use the current value of variables as a start :param str logPath: path to the log file :param gp.Env env: Gurobi environment to use. Default None. :param dict envOptions: environment options. :param bool manageEnv: if False, assume the environment is handled by the user. If ``manageEnv`` is set to True, the ``GUROBI`` object creates a local Gurobi environment and manages all associated Gurobi resources. Importantly, this enables Gurobi licenses to be freed and connections terminated when the ``.close()`` function is called (this function always disposes of the Gurobi model, and the environment):: solver = GUROBI(manageEnv=True) prob.solve(solver) solver.close() # Must be called to free Gurobi resources. # All Gurobi models and environments are freed ``manageEnv=True`` is required when setting license or connection parameters. The ``envOptions`` argument is used to pass parameters to the Gurobi environment. For example, to connect to a Gurobi Cluster Manager:: options = { "CSManager": "<url>", "CSAPIAccessID": "<access-id>", "CSAPISecret": "<api-key>", } solver = GUROBI(manageEnv=True, envOptions=options) solver.close() # Compute server connection terminated Alternatively, one can also pass a ``gp.Env`` object. In this case, to be safe, one should still call ``.close()`` to dispose of the model:: with gp.Env(params=options) as env: # Pass environment as a parameter solver = GUROBI(env=env) prob.solve(solver) solver.close() # Still call `close` as this disposes the model which is required to correctly free env If ``manageEnv`` is set to False (the default), the ``GUROBI`` object uses the global default Gurobi environment which will be freed once the object is deleted. In this case, one can still call ``.close()`` to dispose of the model:: solver = GUROBI() prob.solve(solver) # The global default environment and model remain active solver.close() # Only the global default environment remains active """ self.env = env self.env_options = envOptions if envOptions else {} self.manage_env = False if self.env is not None else manageEnv self.solver_params = solverParams self.model = None self.init_gurobi = False # whether env and model have been initialised LpSolver.__init__( self, mip=mip, msg=msg, timeLimit=timeLimit, gapRel=gapRel, logPath=logPath, warmStart=warmStart, ) # set the output of gurobi if not self.msg: if self.manage_env: self.env_options["OutputFlag"] = 0 else: self.env_options["OutputFlag"] = 0 self.solver_params["OutputFlag"] = 0 def __del__(self): self.close() def close(self): """ Must be called when internal Gurobi model and/or environment requires disposing. The environment (default or otherwise) will be disposed only if ``manageEnv`` is set to True. """ if not self.init_gurobi: return self.model.dispose() if self.manage_env: self.env.dispose() def findSolutionValues(self, lp): model = lp.solverModel solutionStatus = model.Status GRB = gp.GRB # TODO: check status for Integer Feasible gurobiLpStatus = { GRB.OPTIMAL: constants.LpStatusOptimal, GRB.INFEASIBLE: constants.LpStatusInfeasible, GRB.INF_OR_UNBD: constants.LpStatusInfeasible, GRB.UNBOUNDED: constants.LpStatusUnbounded, GRB.ITERATION_LIMIT: constants.LpStatusNotSolved, GRB.NODE_LIMIT: constants.LpStatusNotSolved, GRB.TIME_LIMIT: constants.LpStatusNotSolved, GRB.SOLUTION_LIMIT: constants.LpStatusNotSolved, GRB.INTERRUPTED: constants.LpStatusNotSolved, GRB.NUMERIC: constants.LpStatusNotSolved, } if self.msg: print("Gurobi status=", solutionStatus) lp.resolveOK = True for var in lp._variables: var.isModified = False status = gurobiLpStatus.get(solutionStatus, constants.LpStatusUndefined) lp.assignStatus(status) if model.SolCount >= 1: # populate pulp solution values for var, value in zip( lp._variables, model.getAttr(GRB.Attr.X, model.getVars()) ): var.varValue = value # populate pulp constraints slack for constr, value in zip( lp.constraints.values(), model.getAttr(GRB.Attr.Slack, model.getConstrs()), ): constr.slack = value # put pi and slack variables against the constraints if not model.IsMIP: for var, value in zip( lp._variables, model.getAttr(GRB.Attr.RC, model.getVars()) ): var.dj = value for constr, value in zip( lp.constraints.values(), model.getAttr(GRB.Attr.Pi, model.getConstrs()), ): constr.pi = value return status def available(self): """True if the solver is available""" try: with gp.Env(params=self.env_options): pass except gp.GurobiError as e: warnings.warn(f"GUROBI error: {e}.") return False return True def initGurobi(self): if self.init_gurobi: return else: self.init_gurobi = True try: if self.manage_env: self.env = gp.Env(params=self.env_options) self.model = gp.Model(env=self.env) # Environment handled by user or default Env else: self.model = gp.Model(env=self.env) # Set solver parameters for param, value in self.solver_params.items(): self.model.setParam(param, value) except gp.GurobiError as e: raise e def callSolver(self, lp, callback=None): """Solves the problem with gurobi""" # solve the problem self.solveTime = -clock() lp.solverModel.optimize(callback=callback) self.solveTime += clock() def buildSolverModel(self, lp): """ Takes the pulp lp model and translates it into a gurobi model """ log.debug("create the gurobi model") self.initGurobi() self.model.ModelName = lp.name lp.solverModel = self.model log.debug("set the sense of the problem") if lp.sense == constants.LpMaximize: lp.solverModel.setAttr("ModelSense", -1) if self.timeLimit: lp.solverModel.setParam("TimeLimit", self.timeLimit) gapRel = self.optionsDict.get("gapRel") logPath = self.optionsDict.get("logPath") if gapRel: lp.solverModel.setParam("MIPGap", gapRel) if logPath: lp.solverModel.setParam("LogFile", logPath) log.debug("add the variables to the problem") lp.solverModel.update() nvars = lp.solverModel.NumVars for var in lp.variables(): lowBound = var.lowBound if lowBound is None: lowBound = -gp.GRB.INFINITY upBound = var.upBound if upBound is None: upBound = gp.GRB.INFINITY obj = lp.objective.get(var, 0.0) varType = gp.GRB.CONTINUOUS if var.cat == constants.LpInteger and self.mip: varType = gp.GRB.INTEGER # only add variable once, ow new variable will be created. if not hasattr(var, "solverVar") or nvars == 0: var.solverVar = lp.solverModel.addVar( lowBound, upBound, vtype=varType, obj=obj, name=var.name ) if self.optionsDict.get("warmStart", False): # Once lp.variables() has been used at least once in the building of the model. # we can use the lp._variables with the cache. for var in lp._variables: if var.varValue is not None: var.solverVar.start = var.varValue lp.solverModel.update() log.debug("add the Constraints to the problem") for name, constraint in lp.constraints.items(): # build the expression expr = gp.LinExpr( list(constraint.values()), [v.solverVar for v in constraint.keys()] ) if constraint.sense == constants.LpConstraintLE: constraint.solverConstraint = lp.solverModel.addConstr( expr <= -constraint.constant, name=name ) elif constraint.sense == constants.LpConstraintGE: constraint.solverConstraint = lp.solverModel.addConstr( expr >= -constraint.constant, name=name ) elif constraint.sense == constants.LpConstraintEQ: constraint.solverConstraint = lp.solverModel.addConstr( expr == -constraint.constant, name=name ) else: raise PulpSolverError("Detected an invalid constraint type") lp.solverModel.update() def actualSolve(self, lp, callback=None): """ Solve a well formulated lp problem creates a gurobi model, variables and constraints and attaches them to the lp model which it then solves """ self.buildSolverModel(lp) # set the initial solution log.debug("Solve the Model using gurobi") self.callSolver(lp, callback=callback) # get the solution information solutionStatus = self.findSolutionValues(lp) for var in lp._variables: var.modified = False for constraint in lp.constraints.values(): constraint.modified = False return solutionStatus def actualResolve(self, lp, callback=None): """ Solve a well formulated lp problem uses the old solver and modifies the rhs of the modified constraints """ log.debug("Resolve the Model using gurobi") for constraint in lp.constraints.values(): if constraint.modified: constraint.solverConstraint.setAttr( gp.GRB.Attr.RHS, -constraint.constant ) lp.solverModel.update() self.callSolver(lp, callback=callback) # get the solution information solutionStatus = self.findSolutionValues(lp) for var in lp._variables: var.modified = False for constraint in lp.constraints.values(): constraint.modified = False return solutionStatus
(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)
38,400
pulp.apis.gurobi_api
actualSolve
Solve a well formulated lp problem
def actualSolve(self, lp, callback=None): """Solve a well formulated lp problem""" raise PulpSolverError("GUROBI: Not Available")
(self, lp, callback=None)
38,409
pulp.apis.gurobi_api
GUROBI_CMD
The GUROBI_CMD solver
class GUROBI_CMD(LpSolver_CMD): """The GUROBI_CMD solver""" name = "GUROBI_CMD" def __init__( self, mip=True, msg=True, timeLimit=None, gapRel=None, gapAbs=None, options=None, warmStart=False, keepFiles=False, path=None, threads=None, logPath=None, mip_start=False, ): """ :param bool mip: if False, assume LP even if integer variables :param bool msg: if False, no log is shown :param float timeLimit: maximum time for solver (in seconds) :param float gapRel: relative gap tolerance for the solver to stop (in fraction) :param float gapAbs: absolute gap tolerance for the solver to stop :param int threads: sets the maximum number of threads :param list options: list of additional options to pass to solver :param bool warmStart: if True, the solver will use the current value of variables as a start :param bool keepFiles: if True, files are saved in the current directory and not deleted after solving :param str path: path to the solver binary :param str logPath: path to the log file """ LpSolver_CMD.__init__( self, gapRel=gapRel, mip=mip, msg=msg, timeLimit=timeLimit, options=options, warmStart=warmStart, path=path, keepFiles=keepFiles, threads=threads, gapAbs=gapAbs, logPath=logPath, ) def defaultPath(self): return self.executableExtension("gurobi_cl") def available(self): """True if the solver is available""" if not self.executable(self.path): return False # we execute gurobi once to check the return code. # this is to test that the license is active result = subprocess.Popen( self.path, stdout=subprocess.PIPE, universal_newlines=True ) out, err = result.communicate() if result.returncode == 0: # normal execution return True # error: we display the gurobi message warnings.warn(f"GUROBI error: {out}.") return False def actualSolve(self, lp): """Solve a well formulated lp problem""" if not self.executable(self.path): raise PulpSolverError("PuLP: cannot execute " + self.path) tmpLp, tmpSol, tmpMst = self.create_tmp_files(lp.name, "lp", "sol", "mst") vs = lp.writeLP(tmpLp, writeSOS=1) try: os.remove(tmpSol) except: pass cmd = self.path options = self.options + self.getOptions() if self.timeLimit is not None: options.append(("TimeLimit", self.timeLimit)) cmd += " " + " ".join([f"{key}={value}" for key, value in options]) cmd += f" ResultFile={tmpSol}" if self.optionsDict.get("warmStart", False): self.writesol(filename=tmpMst, vs=vs) cmd += f" InputFile={tmpMst}" if lp.isMIP(): if not self.mip: warnings.warn("GUROBI_CMD does not allow a problem to be relaxed") cmd += f" {tmpLp}" if self.msg: pipe = None else: pipe = open(os.devnull, "w") return_code = subprocess.call(cmd.split(), stdout=pipe, stderr=pipe) # Close the pipe now if we used it. if pipe is not None: pipe.close() if return_code != 0: raise PulpSolverError("PuLP: Error while trying to execute " + self.path) if not os.path.exists(tmpSol): # TODO: the status should be infeasible here, I think status = constants.LpStatusNotSolved values = reducedCosts = shadowPrices = slacks = None else: # TODO: the status should be infeasible here, I think status, values, reducedCosts, shadowPrices, slacks = self.readsol(tmpSol) self.delete_tmp_files(tmpLp, tmpMst, tmpSol, "gurobi.log") if status != constants.LpStatusInfeasible: lp.assignVarsVals(values) lp.assignVarsDj(reducedCosts) lp.assignConsPi(shadowPrices) lp.assignConsSlack(slacks) lp.assignStatus(status) return status def readsol(self, filename): """Read a Gurobi solution file""" with open(filename) as my_file: try: next(my_file) # skip the objective value except StopIteration: # Empty file not solved status = constants.LpStatusNotSolved return status, {}, {}, {}, {} # We have no idea what the status is assume optimal # TODO: check status for Integer Feasible status = constants.LpStatusOptimal shadowPrices = {} slacks = {} shadowPrices = {} slacks = {} values = {} reducedCosts = {} for line in my_file: if line[0] != "#": # skip comments name, value = line.split() values[name] = float(value) return status, values, reducedCosts, shadowPrices, slacks def writesol(self, filename, vs): """Writes a GUROBI solution file""" values = [(v.name, v.value()) for v in vs if v.value() is not None] rows = [] for name, value in values: rows.append(f"{name} {value}") with open(filename, "w") as f: f.write("\n".join(rows)) return True def getOptions(self): # GUROBI parameters: http://www.gurobi.com/documentation/7.5/refman/parameters.html#sec:Parameters params_eq = dict( logPath="LogFile", gapRel="MIPGap", gapAbs="MIPGapAbs", threads="Threads", ) return [ (v, self.optionsDict[k]) for k, v in params_eq.items() if k in self.optionsDict and self.optionsDict[k] is not None ]
(mip=True, msg=True, timeLimit=None, gapRel=None, gapAbs=None, options=None, warmStart=False, keepFiles=False, path=None, threads=None, logPath=None, mip_start=False)
38,410
pulp.apis.gurobi_api
__init__
:param bool mip: if False, assume LP even if integer variables :param bool msg: if False, no log is shown :param float timeLimit: maximum time for solver (in seconds) :param float gapRel: relative gap tolerance for the solver to stop (in fraction) :param float gapAbs: absolute gap tolerance for the solver to stop :param int threads: sets the maximum number of threads :param list options: list of additional options to pass to solver :param bool warmStart: if True, the solver will use the current value of variables as a start :param bool keepFiles: if True, files are saved in the current directory and not deleted after solving :param str path: path to the solver binary :param str logPath: path to the log file
def __init__( self, mip=True, msg=True, timeLimit=None, gapRel=None, gapAbs=None, options=None, warmStart=False, keepFiles=False, path=None, threads=None, logPath=None, mip_start=False, ): """ :param bool mip: if False, assume LP even if integer variables :param bool msg: if False, no log is shown :param float timeLimit: maximum time for solver (in seconds) :param float gapRel: relative gap tolerance for the solver to stop (in fraction) :param float gapAbs: absolute gap tolerance for the solver to stop :param int threads: sets the maximum number of threads :param list options: list of additional options to pass to solver :param bool warmStart: if True, the solver will use the current value of variables as a start :param bool keepFiles: if True, files are saved in the current directory and not deleted after solving :param str path: path to the solver binary :param str logPath: path to the log file """ LpSolver_CMD.__init__( self, gapRel=gapRel, mip=mip, msg=msg, timeLimit=timeLimit, options=options, warmStart=warmStart, path=path, keepFiles=keepFiles, threads=threads, gapAbs=gapAbs, logPath=logPath, )
(self, mip=True, msg=True, timeLimit=None, gapRel=None, gapAbs=None, options=None, warmStart=False, keepFiles=False, path=None, threads=None, logPath=None, mip_start=False)
38,412
pulp.apis.gurobi_api
actualSolve
Solve a well formulated lp problem
def actualSolve(self, lp): """Solve a well formulated lp problem""" if not self.executable(self.path): raise PulpSolverError("PuLP: cannot execute " + self.path) tmpLp, tmpSol, tmpMst = self.create_tmp_files(lp.name, "lp", "sol", "mst") vs = lp.writeLP(tmpLp, writeSOS=1) try: os.remove(tmpSol) except: pass cmd = self.path options = self.options + self.getOptions() if self.timeLimit is not None: options.append(("TimeLimit", self.timeLimit)) cmd += " " + " ".join([f"{key}={value}" for key, value in options]) cmd += f" ResultFile={tmpSol}" if self.optionsDict.get("warmStart", False): self.writesol(filename=tmpMst, vs=vs) cmd += f" InputFile={tmpMst}" if lp.isMIP(): if not self.mip: warnings.warn("GUROBI_CMD does not allow a problem to be relaxed") cmd += f" {tmpLp}" if self.msg: pipe = None else: pipe = open(os.devnull, "w") return_code = subprocess.call(cmd.split(), stdout=pipe, stderr=pipe) # Close the pipe now if we used it. if pipe is not None: pipe.close() if return_code != 0: raise PulpSolverError("PuLP: Error while trying to execute " + self.path) if not os.path.exists(tmpSol): # TODO: the status should be infeasible here, I think status = constants.LpStatusNotSolved values = reducedCosts = shadowPrices = slacks = None else: # TODO: the status should be infeasible here, I think status, values, reducedCosts, shadowPrices, slacks = self.readsol(tmpSol) self.delete_tmp_files(tmpLp, tmpMst, tmpSol, "gurobi.log") if status != constants.LpStatusInfeasible: lp.assignVarsVals(values) lp.assignVarsDj(reducedCosts) lp.assignConsPi(shadowPrices) lp.assignConsSlack(slacks) lp.assignStatus(status) return status
(self, lp)
38,413
pulp.apis.gurobi_api
available
True if the solver is available
def available(self): """True if the solver is available""" if not self.executable(self.path): return False # we execute gurobi once to check the return code. # this is to test that the license is active result = subprocess.Popen( self.path, stdout=subprocess.PIPE, universal_newlines=True ) out, err = result.communicate() if result.returncode == 0: # normal execution return True # error: we display the gurobi message warnings.warn(f"GUROBI error: {out}.") return False
(self)
38,416
pulp.apis.gurobi_api
defaultPath
null
def defaultPath(self): return self.executableExtension("gurobi_cl")
(self)
38,421
pulp.apis.gurobi_api
getOptions
null
def getOptions(self): # GUROBI parameters: http://www.gurobi.com/documentation/7.5/refman/parameters.html#sec:Parameters params_eq = dict( logPath="LogFile", gapRel="MIPGap", gapAbs="MIPGapAbs", threads="Threads", ) return [ (v, self.optionsDict[k]) for k, v in params_eq.items() if k in self.optionsDict and self.optionsDict[k] is not None ]
(self)
38,422
pulp.apis.gurobi_api
readsol
Read a Gurobi solution file
def readsol(self, filename): """Read a Gurobi solution file""" with open(filename) as my_file: try: next(my_file) # skip the objective value except StopIteration: # Empty file not solved status = constants.LpStatusNotSolved return status, {}, {}, {}, {} # We have no idea what the status is assume optimal # TODO: check status for Integer Feasible status = constants.LpStatusOptimal shadowPrices = {} slacks = {} shadowPrices = {} slacks = {} values = {} reducedCosts = {} for line in my_file: if line[0] != "#": # skip comments name, value = line.split() values[name] = float(value) return status, values, reducedCosts, shadowPrices, slacks
(self, filename)
38,430
pulp.apis.gurobi_api
writesol
Writes a GUROBI solution file
def writesol(self, filename, vs): """Writes a GUROBI solution file""" values = [(v.name, v.value()) for v in vs if v.value() is not None] rows = [] for name, value in values: rows.append(f"{name} {value}") with open(filename, "w") as f: f.write("\n".join(rows)) return True
(self, filename, vs)
38,431
pulp.apis.highs_api
HiGHS
null
class HiGHS(LpSolver): name = "HiGHS" try: global highspy import highspy except: def available(self): """True if the solver is available""" return False def actualSolve(self, lp, callback=None): """Solve a well formulated lp problem""" raise PulpSolverError("HiGHS: Not Available") else: # Note(maciej): It was surprising to me that higshpy wasn't logging out of the box, # even with the different logging options set. This callback seems to work, but there # are probably better ways of doing this ¯\_(ツ)_/¯ DEFAULT_CALLBACK = lambda logType, logMsg, callbackValue: print( f"[{logType.name}] {logMsg}" ) DEFAULT_CALLBACK_VALUE = "" def __init__( self, mip=True, msg=True, callbackTuple=None, gapAbs=None, gapRel=None, threads=None, timeLimit=None, **solverParams, ): """ :param bool mip: if False, assume LP even if integer variables :param bool msg: if False, no log is shown :param tuple callbackTuple: Tuple of log callback function (see DEFAULT_CALLBACK above for definition) and callbackValue (tag embedded in every callback) :param float gapRel: relative gap tolerance for the solver to stop (in fraction) :param float gapAbs: absolute gap tolerance for the solver to stop :param int threads: sets the maximum number of threads :param float timeLimit: maximum time for solver (in seconds) :param dict solverParams: list of named options to pass directly to the HiGHS solver """ super().__init__(mip=mip, msg=msg, timeLimit=timeLimit, **solverParams) self.callbackTuple = callbackTuple self.gapAbs = gapAbs self.gapRel = gapRel self.threads = threads def available(self): return True def callSolver(self, lp): lp.solverModel.run() def createAndConfigureSolver(self, lp): lp.solverModel = highspy.Highs() if self.msg or self.callbackTuple: callbackTuple = self.callbackTuple or ( HiGHS.DEFAULT_CALLBACK, HiGHS.DEFAULT_CALLBACK_VALUE, ) lp.solverModel.setLogCallback(*callbackTuple) if self.gapRel is not None: lp.solverModel.setOptionValue("mip_rel_gap", self.gapRel) if self.gapAbs is not None: lp.solverModel.setOptionValue("mip_abs_gap", self.gapAbs) if self.threads is not None: lp.solverModel.setOptionValue("threads", self.threads) if self.timeLimit is not None: lp.solverModel.setOptionValue("time_limit", float(self.timeLimit)) # set remaining parameter values for key, value in self.optionsDict.items(): lp.solverModel.setOptionValue(key, value) def buildSolverModel(self, lp): inf = highspy.kHighsInf obj_mult = -1 if lp.sense == constants.LpMaximize else 1 for i, var in enumerate(lp.variables()): lb = var.lowBound ub = var.upBound lp.solverModel.addCol( obj_mult * lp.objective.get(var, 0.0), -inf if lb is None else lb, inf if ub is None else ub, 0, [], [], ) var.index = i if var.cat == constants.LpInteger and self.mip: lp.solverModel.changeColIntegrality( var.index, highspy.HighsVarType.kInteger ) for constraint in lp.constraints.values(): non_zero_constraint_items = [ (var.index, coefficient) for var, coefficient in constraint.items() if coefficient != 0 ] if len(non_zero_constraint_items) == 0: indices, coefficients = [], [] else: indices, coefficients = zip(*non_zero_constraint_items) lb = constraint.getLb() ub = constraint.getUb() lp.solverModel.addRow( -inf if lb is None else lb, inf if ub is None else ub, len(indices), indices, coefficients, ) def findSolutionValues(self, lp): status = lp.solverModel.getModelStatus() obj_value = lp.solverModel.getObjectiveValue() solution = lp.solverModel.getSolution() HighsModelStatus = highspy.HighsModelStatus status_dict = { HighsModelStatus.kNotset: ( constants.LpStatusNotSolved, constants.LpSolutionNoSolutionFound, ), HighsModelStatus.kLoadError: ( constants.LpStatusNotSolved, constants.LpSolutionNoSolutionFound, ), HighsModelStatus.kModelError: ( constants.LpStatusNotSolved, constants.LpSolutionNoSolutionFound, ), HighsModelStatus.kPresolveError: ( constants.LpStatusNotSolved, constants.LpSolutionNoSolutionFound, ), HighsModelStatus.kSolveError: ( constants.LpStatusNotSolved, constants.LpSolutionNoSolutionFound, ), HighsModelStatus.kPostsolveError: ( constants.LpStatusNotSolved, constants.LpSolutionNoSolutionFound, ), HighsModelStatus.kModelEmpty: ( constants.LpStatusNotSolved, constants.LpSolutionNoSolutionFound, ), HighsModelStatus.kOptimal: ( constants.LpStatusOptimal, constants.LpSolutionOptimal, ), HighsModelStatus.kInfeasible: ( constants.LpStatusInfeasible, constants.LpSolutionInfeasible, ), HighsModelStatus.kUnboundedOrInfeasible: ( constants.LpStatusInfeasible, constants.LpSolutionInfeasible, ), HighsModelStatus.kUnbounded: ( constants.LpStatusUnbounded, constants.LpSolutionUnbounded, ), HighsModelStatus.kObjectiveBound: ( constants.LpStatusOptimal, constants.LpSolutionIntegerFeasible, ), HighsModelStatus.kObjectiveTarget: ( constants.LpStatusOptimal, constants.LpSolutionIntegerFeasible, ), HighsModelStatus.kTimeLimit: ( constants.LpStatusOptimal, constants.LpSolutionIntegerFeasible, ), HighsModelStatus.kIterationLimit: ( constants.LpStatusOptimal, constants.LpSolutionIntegerFeasible, ), HighsModelStatus.kUnknown: ( constants.LpStatusNotSolved, constants.LpSolutionNoSolutionFound, ), } col_values = list(solution.col_value) # Assign values to the variables as with lp.assignVarsVals() for var in lp.variables(): var.varValue = col_values[var.index] if obj_value == float(inf) and status in ( HighsModelStatus.kTimeLimit, HighsModelStatus.kIterationLimit, ): return constants.LpStatusNotSolved, constants.LpSolutionNoSolutionFound else: return status_dict[status] def actualSolve(self, lp): self.createAndConfigureSolver(lp) self.buildSolverModel(lp) self.callSolver(lp) status, sol_status = self.findSolutionValues(lp) for var in lp.variables(): var.modified = False for constraint in lp.constraints.values(): constraint.modifier = False lp.assignStatus(status, sol_status) return status def actualResolve(self, lp, **kwargs): raise PulpSolverError("HiGHS: Resolving is not supported")
(mip=True, msg=True, options=None, timeLimit=None, *args, **kwargs)
38,434
pulp.apis.highs_api
actualSolve
Solve a well formulated lp problem
def actualSolve(self, lp, callback=None): """Solve a well formulated lp problem""" raise PulpSolverError("HiGHS: Not Available")
(self, lp, callback=None)
38,443
pulp.apis.highs_api
HiGHS_CMD
The HiGHS_CMD solver
class HiGHS_CMD(LpSolver_CMD): """The HiGHS_CMD solver""" name: str = "HiGHS_CMD" SOLUTION_STYLE: int = 0 def __init__( self, path=None, keepFiles=False, mip=True, msg=True, options=None, timeLimit=None, gapRel=None, gapAbs=None, threads=None, logPath=None, warmStart=False, ): """ :param bool mip: if False, assume LP even if integer variables :param bool msg: if False, no log is shown :param float timeLimit: maximum time for solver (in seconds) :param float gapRel: relative gap tolerance for the solver to stop (in fraction) :param float gapAbs: absolute gap tolerance for the solver to stop :param list[str] options: list of additional options to pass to solver :param bool keepFiles: if True, files are saved in the current directory and not deleted after solving :param str path: path to the solver binary (you can get binaries for your platform from https://github.com/JuliaBinaryWrappers/HiGHS_jll.jl/releases, or else compile from source - https://highs.dev) :param int threads: sets the maximum number of threads :param str logPath: path to the log file :param bool warmStart: if True, the solver will use the current value of variables as a start """ LpSolver_CMD.__init__( self, mip=mip, msg=msg, timeLimit=timeLimit, gapRel=gapRel, gapAbs=gapAbs, options=options, path=path, keepFiles=keepFiles, threads=threads, logPath=logPath, warmStart=warmStart, ) def defaultPath(self): return self.executableExtension("highs") def available(self): """True if the solver is available""" return self.executable(self.path) def actualSolve(self, lp): """Solve a well formulated lp problem""" if not self.executable(self.path): raise PulpSolverError("PuLP: cannot execute " + self.path) lp.checkDuplicateVars() tmpMps, tmpSol, tmpOptions, tmpLog, tmpMst = self.create_tmp_files( lp.name, "mps", "sol", "HiGHS", "HiGHS_log", "mst" ) lp.writeMPS(tmpMps, with_objsense=True) file_options: List[str] = [] file_options.append(f"solution_file={tmpSol}") file_options.append("write_solution_to_file=true") file_options.append(f"write_solution_style={HiGHS_CMD.SOLUTION_STYLE}") if not self.msg: file_options.append("log_to_console=false") if "threads" in self.optionsDict: file_options.append(f"threads={self.optionsDict['threads']}") if "gapRel" in self.optionsDict: file_options.append(f"mip_rel_gap={self.optionsDict['gapRel']}") if "gapAbs" in self.optionsDict: file_options.append(f"mip_abs_gap={self.optionsDict['gapAbs']}") if "logPath" in self.optionsDict: highs_log_file = self.optionsDict["logPath"] else: highs_log_file = tmpLog file_options.append(f"log_file={highs_log_file}") command: List[str] = [] command.append(self.path) command.append(tmpMps) command.append(f"--options_file={tmpOptions}") if self.timeLimit is not None: command.append(f"--time_limit={self.timeLimit}") if not self.mip: command.append("--solver=simplex") if "threads" in self.optionsDict: command.append("--parallel=on") if self.optionsDict.get("warmStart", False): self.writesol(tmpMst, lp) command.append(f"--read_solution_file={tmpMst}") options = iter(self.options) for option in options: # assumption: all cli and file options require an argument which is provided after the equal sign (=) if "=" not in option: option += f"={next(options)}" # identify cli options by a leading dash (-) and treat other options as file options if option.startswith("-"): command.append(option) else: file_options.append(option) with open(tmpOptions, "w") as options_file: options_file.write("\n".join(file_options)) process = subprocess.run(command, stdout=sys.stdout, stderr=sys.stderr) # HiGHS return code semantics (see: https://github.com/ERGO-Code/HiGHS/issues/527#issuecomment-946575028) # - -1: error # - 0: success # - 1: warning if process.returncode == -1: raise PulpSolverError("Error while executing HiGHS") with open(highs_log_file, "r") as log_file: lines = log_file.readlines() lines = [line.strip().split() for line in lines] # LP model_line = [line for line in lines if line[:2] == ["Model", "status"]] if len(model_line) > 0: model_status = " ".join(model_line[0][3:]) # Model status: ... else: # ILP model_line = [line for line in lines if "Status" in line][0] model_status = " ".join(model_line[1:]) sol_line = [line for line in lines if line[:2] == ["Solution", "status"]] sol_line = sol_line[0] if len(sol_line) > 0 else ["Not solved"] sol_status = sol_line[-1] if model_status.lower() == "optimal": # optimal status, status_sol = ( constants.LpStatusOptimal, constants.LpSolutionOptimal, ) elif sol_status.lower() == "feasible": # feasible # Following the PuLP convention status, status_sol = ( constants.LpStatusOptimal, constants.LpSolutionIntegerFeasible, ) elif model_status.lower() == "infeasible": # infeasible status, status_sol = ( constants.LpStatusInfeasible, constants.LpSolutionInfeasible, ) elif model_status.lower() == "unbounded": # unbounded status, status_sol = ( constants.LpStatusUnbounded, constants.LpSolutionUnbounded, ) else: # no solution status, status_sol = ( constants.LpStatusNotSolved, constants.LpSolutionNoSolutionFound, ) if not os.path.exists(tmpSol) or os.stat(tmpSol).st_size == 0: status_sol = constants.LpSolutionNoSolutionFound values = None elif status_sol == constants.LpSolutionNoSolutionFound: values = None else: values = self.readsol(tmpSol) self.delete_tmp_files(tmpMps, tmpSol, tmpOptions, tmpLog, tmpMst) lp.assignStatus(status, status_sol) if status == constants.LpStatusOptimal: lp.assignVarsVals(values) return status def writesol(self, filename, lp): """Writes a HiGHS solution file""" variable_rows = [] for var in lp.variables(): # zero variables must be included variable_rows.append(f"{var.name} {var.varValue or 0}") # Required preamble for HiGHS to accept a solution all_rows = [ "Model status", "None", "", "# Primal solution values", "Feasible", "", f"# Columns {len(variable_rows)}", ] all_rows.extend(variable_rows) with open(filename, "w") as file: file.write("\n".join(all_rows)) def readsol(self, filename): """Read a HiGHS solution file""" with open(filename) as file: lines = file.readlines() begin, end = None, None for index, line in enumerate(lines): if begin is None and line.startswith("# Columns"): begin = index + 1 if end is None and line.startswith("# Rows"): end = index if begin is None or end is None: raise PulpSolverError("Cannot read HiGHS solver output") values = {} for line in lines[begin:end]: name, value = line.split() values[name] = float(value) return values
(path=None, keepFiles=False, mip=True, msg=True, options=None, timeLimit=None, gapRel=None, gapAbs=None, threads=None, logPath=None, warmStart=False)
38,444
pulp.apis.highs_api
__init__
:param bool mip: if False, assume LP even if integer variables :param bool msg: if False, no log is shown :param float timeLimit: maximum time for solver (in seconds) :param float gapRel: relative gap tolerance for the solver to stop (in fraction) :param float gapAbs: absolute gap tolerance for the solver to stop :param list[str] options: list of additional options to pass to solver :param bool keepFiles: if True, files are saved in the current directory and not deleted after solving :param str path: path to the solver binary (you can get binaries for your platform from https://github.com/JuliaBinaryWrappers/HiGHS_jll.jl/releases, or else compile from source - https://highs.dev) :param int threads: sets the maximum number of threads :param str logPath: path to the log file :param bool warmStart: if True, the solver will use the current value of variables as a start
def __init__( self, path=None, keepFiles=False, mip=True, msg=True, options=None, timeLimit=None, gapRel=None, gapAbs=None, threads=None, logPath=None, warmStart=False, ): """ :param bool mip: if False, assume LP even if integer variables :param bool msg: if False, no log is shown :param float timeLimit: maximum time for solver (in seconds) :param float gapRel: relative gap tolerance for the solver to stop (in fraction) :param float gapAbs: absolute gap tolerance for the solver to stop :param list[str] options: list of additional options to pass to solver :param bool keepFiles: if True, files are saved in the current directory and not deleted after solving :param str path: path to the solver binary (you can get binaries for your platform from https://github.com/JuliaBinaryWrappers/HiGHS_jll.jl/releases, or else compile from source - https://highs.dev) :param int threads: sets the maximum number of threads :param str logPath: path to the log file :param bool warmStart: if True, the solver will use the current value of variables as a start """ LpSolver_CMD.__init__( self, mip=mip, msg=msg, timeLimit=timeLimit, gapRel=gapRel, gapAbs=gapAbs, options=options, path=path, keepFiles=keepFiles, threads=threads, logPath=logPath, warmStart=warmStart, )
(self, path=None, keepFiles=False, mip=True, msg=True, options=None, timeLimit=None, gapRel=None, gapAbs=None, threads=None, logPath=None, warmStart=False)
38,446
pulp.apis.highs_api
actualSolve
Solve a well formulated lp problem
def actualSolve(self, lp): """Solve a well formulated lp problem""" if not self.executable(self.path): raise PulpSolverError("PuLP: cannot execute " + self.path) lp.checkDuplicateVars() tmpMps, tmpSol, tmpOptions, tmpLog, tmpMst = self.create_tmp_files( lp.name, "mps", "sol", "HiGHS", "HiGHS_log", "mst" ) lp.writeMPS(tmpMps, with_objsense=True) file_options: List[str] = [] file_options.append(f"solution_file={tmpSol}") file_options.append("write_solution_to_file=true") file_options.append(f"write_solution_style={HiGHS_CMD.SOLUTION_STYLE}") if not self.msg: file_options.append("log_to_console=false") if "threads" in self.optionsDict: file_options.append(f"threads={self.optionsDict['threads']}") if "gapRel" in self.optionsDict: file_options.append(f"mip_rel_gap={self.optionsDict['gapRel']}") if "gapAbs" in self.optionsDict: file_options.append(f"mip_abs_gap={self.optionsDict['gapAbs']}") if "logPath" in self.optionsDict: highs_log_file = self.optionsDict["logPath"] else: highs_log_file = tmpLog file_options.append(f"log_file={highs_log_file}") command: List[str] = [] command.append(self.path) command.append(tmpMps) command.append(f"--options_file={tmpOptions}") if self.timeLimit is not None: command.append(f"--time_limit={self.timeLimit}") if not self.mip: command.append("--solver=simplex") if "threads" in self.optionsDict: command.append("--parallel=on") if self.optionsDict.get("warmStart", False): self.writesol(tmpMst, lp) command.append(f"--read_solution_file={tmpMst}") options = iter(self.options) for option in options: # assumption: all cli and file options require an argument which is provided after the equal sign (=) if "=" not in option: option += f"={next(options)}" # identify cli options by a leading dash (-) and treat other options as file options if option.startswith("-"): command.append(option) else: file_options.append(option) with open(tmpOptions, "w") as options_file: options_file.write("\n".join(file_options)) process = subprocess.run(command, stdout=sys.stdout, stderr=sys.stderr) # HiGHS return code semantics (see: https://github.com/ERGO-Code/HiGHS/issues/527#issuecomment-946575028) # - -1: error # - 0: success # - 1: warning if process.returncode == -1: raise PulpSolverError("Error while executing HiGHS") with open(highs_log_file, "r") as log_file: lines = log_file.readlines() lines = [line.strip().split() for line in lines] # LP model_line = [line for line in lines if line[:2] == ["Model", "status"]] if len(model_line) > 0: model_status = " ".join(model_line[0][3:]) # Model status: ... else: # ILP model_line = [line for line in lines if "Status" in line][0] model_status = " ".join(model_line[1:]) sol_line = [line for line in lines if line[:2] == ["Solution", "status"]] sol_line = sol_line[0] if len(sol_line) > 0 else ["Not solved"] sol_status = sol_line[-1] if model_status.lower() == "optimal": # optimal status, status_sol = ( constants.LpStatusOptimal, constants.LpSolutionOptimal, ) elif sol_status.lower() == "feasible": # feasible # Following the PuLP convention status, status_sol = ( constants.LpStatusOptimal, constants.LpSolutionIntegerFeasible, ) elif model_status.lower() == "infeasible": # infeasible status, status_sol = ( constants.LpStatusInfeasible, constants.LpSolutionInfeasible, ) elif model_status.lower() == "unbounded": # unbounded status, status_sol = ( constants.LpStatusUnbounded, constants.LpSolutionUnbounded, ) else: # no solution status, status_sol = ( constants.LpStatusNotSolved, constants.LpSolutionNoSolutionFound, ) if not os.path.exists(tmpSol) or os.stat(tmpSol).st_size == 0: status_sol = constants.LpSolutionNoSolutionFound values = None elif status_sol == constants.LpSolutionNoSolutionFound: values = None else: values = self.readsol(tmpSol) self.delete_tmp_files(tmpMps, tmpSol, tmpOptions, tmpLog, tmpMst) lp.assignStatus(status, status_sol) if status == constants.LpStatusOptimal: lp.assignVarsVals(values) return status
(self, lp)
38,450
pulp.apis.highs_api
defaultPath
null
def defaultPath(self): return self.executableExtension("highs")
(self)
38,455
pulp.apis.highs_api
readsol
Read a HiGHS solution file
def readsol(self, filename): """Read a HiGHS solution file""" with open(filename) as file: lines = file.readlines() begin, end = None, None for index, line in enumerate(lines): if begin is None and line.startswith("# Columns"): begin = index + 1 if end is None and line.startswith("# Rows"): end = index if begin is None or end is None: raise PulpSolverError("Cannot read HiGHS solver output") values = {} for line in lines[begin:end]: name, value = line.split() values[name] = float(value) return values
(self, filename)
38,463
pulp.apis.highs_api
writesol
Writes a HiGHS solution file
def writesol(self, filename, lp): """Writes a HiGHS solution file""" variable_rows = [] for var in lp.variables(): # zero variables must be included variable_rows.append(f"{var.name} {var.varValue or 0}") # Required preamble for HiGHS to accept a solution all_rows = [ "Model status", "None", "", "# Primal solution values", "Feasible", "", f"# Columns {len(variable_rows)}", ] all_rows.extend(variable_rows) with open(filename, "w") as file: file.write("\n".join(all_rows))
(self, filename, lp)
38,466
pulp.pulp
LpAffineExpression
A linear combination of :class:`LpVariables<LpVariable>`. Can be initialised with the following: #. e = None: an empty Expression #. e = dict: gives an expression with the values being the coefficients of the keys (order of terms is undetermined) #. e = list or generator of 2-tuples: equivalent to dict.items() #. e = LpElement: an expression of length 1 with the coefficient 1 #. e = other: the constant is initialised as e Examples: >>> f=LpAffineExpression(LpElement('x')) >>> f 1*x + 0 >>> x_name = ['x_0', 'x_1', 'x_2'] >>> x = [LpVariable(x_name[i], lowBound = 0, upBound = 10) for i in range(3) ] >>> c = LpAffineExpression([ (x[0],1), (x[1],-3), (x[2],4)]) >>> c 1*x_0 + -3*x_1 + 4*x_2 + 0
class LpAffineExpression(_DICT_TYPE): """ A linear combination of :class:`LpVariables<LpVariable>`. Can be initialised with the following: #. e = None: an empty Expression #. e = dict: gives an expression with the values being the coefficients of the keys (order of terms is undetermined) #. e = list or generator of 2-tuples: equivalent to dict.items() #. e = LpElement: an expression of length 1 with the coefficient 1 #. e = other: the constant is initialised as e Examples: >>> f=LpAffineExpression(LpElement('x')) >>> f 1*x + 0 >>> x_name = ['x_0', 'x_1', 'x_2'] >>> x = [LpVariable(x_name[i], lowBound = 0, upBound = 10) for i in range(3) ] >>> c = LpAffineExpression([ (x[0],1), (x[1],-3), (x[2],4)]) >>> c 1*x_0 + -3*x_1 + 4*x_2 + 0 """ # to remove illegal characters from the names trans = maketrans("-+[] ", "_____") def setName(self, name): if name: self.__name = str(name).translate(self.trans) else: self.__name = None def getName(self): return self.__name name = property(fget=getName, fset=setName) def __init__(self, e=None, constant=0, name=None): self.name = name # TODO remove isinstance usage if e is None: e = {} if isinstance(e, LpAffineExpression): # Will not copy the name self.constant = e.constant super().__init__(list(e.items())) elif isinstance(e, dict): self.constant = constant super().__init__(list(e.items())) elif isinstance(e, Iterable): self.constant = constant super().__init__(e) elif isinstance(e, LpElement): self.constant = 0 super().__init__([(e, 1)]) else: self.constant = e super().__init__() # Proxy functions for variables def isAtomic(self): return len(self) == 1 and self.constant == 0 and list(self.values())[0] == 1 def isNumericalConstant(self): return len(self) == 0 def atom(self): return list(self.keys())[0] # Functions on expressions def __bool__(self): return (float(self.constant) != 0.0) or (len(self) > 0) def value(self): s = self.constant for v, x in self.items(): if v.varValue is None: return None s += v.varValue * x return s def valueOrDefault(self): s = self.constant for v, x in self.items(): s += v.valueOrDefault() * x return s def addterm(self, key, value): y = self.get(key, 0) if y: y += value self[key] = y else: self[key] = value def emptyCopy(self): return LpAffineExpression() def copy(self): """Make a copy of self except the name which is reset""" # Will not copy the name return LpAffineExpression(self) def __str__(self, constant=1): s = "" for v in self.sorted_keys(): val = self[v] if val < 0: if s != "": s += " - " else: s += "-" val = -val elif s != "": s += " + " if val == 1: s += str(v) else: s += str(val) + "*" + str(v) if constant: if s == "": s = str(self.constant) else: if self.constant < 0: s += " - " + str(-self.constant) elif self.constant > 0: s += " + " + str(self.constant) elif s == "": s = "0" return s def sorted_keys(self): """ returns the list of keys sorted by name """ result = [(v.name, v) for v in self.keys()] result.sort() result = [v for _, v in result] return result def __repr__(self): l = [str(self[v]) + "*" + str(v) for v in self.sorted_keys()] l.append(str(self.constant)) s = " + ".join(l) return s @staticmethod def _count_characters(line): # counts the characters in a list of strings return sum(len(t) for t in line) def asCplexVariablesOnly(self, name): """ helper for asCplexLpAffineExpression """ result = [] line = [f"{name}:"] notFirst = 0 variables = self.sorted_keys() for v in variables: val = self[v] if val < 0: sign = " -" val = -val elif notFirst: sign = " +" else: sign = "" notFirst = 1 if val == 1: term = f"{sign} {v.name}" else: # adding zero to val to remove instances of negative zero term = f"{sign} {val + 0:.12g} {v.name}" if self._count_characters(line) + len(term) > const.LpCplexLPLineSize: result += ["".join(line)] line = [term] else: line += [term] return result, line def asCplexLpAffineExpression(self, name, constant=1): """ returns a string that represents the Affine Expression in lp format """ # refactored to use a list for speed in iron python result, line = self.asCplexVariablesOnly(name) if not self: term = f" {self.constant}" else: term = "" if constant: if self.constant < 0: term = " - %s" % (-self.constant) elif self.constant > 0: term = f" + {self.constant}" if self._count_characters(line) + len(term) > const.LpCplexLPLineSize: result += ["".join(line)] line = [term] else: line += [term] result += ["".join(line)] result = "%s\n" % "\n".join(result) return result def addInPlace(self, other): if isinstance(other, int) and (other == 0): return self if other is None: return self if isinstance(other, LpElement): self.addterm(other, 1) elif isinstance(other, LpAffineExpression): self.constant += other.constant for v, x in other.items(): self.addterm(v, x) elif isinstance(other, dict): for e in other.values(): self.addInPlace(e) elif isinstance(other, list) or isinstance(other, Iterable): for e in other: self.addInPlace(e) else: self.constant += other return self def subInPlace(self, other): if isinstance(other, int) and (other == 0): return self if other is None: return self if isinstance(other, LpElement): self.addterm(other, -1) elif isinstance(other, LpAffineExpression): self.constant -= other.constant for v, x in other.items(): self.addterm(v, -x) elif isinstance(other, dict): for e in other.values(): self.subInPlace(e) elif isinstance(other, list) or isinstance(other, Iterable): for e in other: self.subInPlace(e) else: self.constant -= other return self def __neg__(self): e = self.emptyCopy() e.constant = -self.constant for v, x in self.items(): e[v] = -x return e def __pos__(self): return self def __add__(self, other): return self.copy().addInPlace(other) def __radd__(self, other): return self.copy().addInPlace(other) def __iadd__(self, other): return self.addInPlace(other) def __sub__(self, other): return self.copy().subInPlace(other) def __rsub__(self, other): return (-self).addInPlace(other) def __isub__(self, other): return (self).subInPlace(other) def __mul__(self, other): e = self.emptyCopy() if isinstance(other, LpAffineExpression): e.constant = self.constant * other.constant if len(other): if len(self): raise TypeError("Non-constant expressions cannot be multiplied") else: c = self.constant if c != 0: for v, x in other.items(): e[v] = c * x else: c = other.constant if c != 0: for v, x in self.items(): e[v] = c * x elif isinstance(other, LpVariable): return self * LpAffineExpression(other) else: if other != 0: e.constant = self.constant * other for v, x in self.items(): e[v] = other * x return e def __rmul__(self, other): return self * other def __div__(self, other): if isinstance(other, LpAffineExpression) or isinstance(other, LpVariable): if len(other): raise TypeError( "Expressions cannot be divided by a non-constant expression" ) other = other.constant e = self.emptyCopy() e.constant = self.constant / other for v, x in self.items(): e[v] = x / other return e def __truediv__(self, other): if isinstance(other, LpAffineExpression) or isinstance(other, LpVariable): if len(other): raise TypeError( "Expressions cannot be divided by a non-constant expression" ) other = other.constant e = self.emptyCopy() e.constant = self.constant / other for v, x in self.items(): e[v] = x / other return e def __rdiv__(self, other): e = self.emptyCopy() if len(self): raise TypeError( "Expressions cannot be divided by a non-constant expression" ) c = self.constant if isinstance(other, LpAffineExpression): e.constant = other.constant / c for v, x in other.items(): e[v] = x / c else: e.constant = other / c return e def __le__(self, other): return LpConstraint(self - other, const.LpConstraintLE) def __ge__(self, other): return LpConstraint(self - other, const.LpConstraintGE) def __eq__(self, other): return LpConstraint(self - other, const.LpConstraintEQ) def toDict(self): """ exports the :py:class:`LpAffineExpression` into a list of dictionaries with the coefficients it does not export the constant :return: list of dictionaries with the coefficients :rtype: list """ return [dict(name=k.name, value=v) for k, v in self.items()] to_dict = toDict
(e=None, constant=0, name=None)
38,467
pulp.pulp
__add__
null
def __add__(self, other): return self.copy().addInPlace(other)
(self, other)
38,468
pulp.pulp
__bool__
null
def __bool__(self): return (float(self.constant) != 0.0) or (len(self) > 0)
(self)
38,469
pulp.pulp
__div__
null
def __div__(self, other): if isinstance(other, LpAffineExpression) or isinstance(other, LpVariable): if len(other): raise TypeError( "Expressions cannot be divided by a non-constant expression" ) other = other.constant e = self.emptyCopy() e.constant = self.constant / other for v, x in self.items(): e[v] = x / other return e
(self, other)
38,470
pulp.pulp
__eq__
null
def __eq__(self, other): return LpConstraint(self - other, const.LpConstraintEQ)
(self, other)
38,471
pulp.pulp
__ge__
null
def __ge__(self, other): return LpConstraint(self - other, const.LpConstraintGE)
(self, other)
38,472
pulp.pulp
__iadd__
null
def __iadd__(self, other): return self.addInPlace(other)
(self, other)
38,473
pulp.pulp
__init__
null
def __init__(self, e=None, constant=0, name=None): self.name = name # TODO remove isinstance usage if e is None: e = {} if isinstance(e, LpAffineExpression): # Will not copy the name self.constant = e.constant super().__init__(list(e.items())) elif isinstance(e, dict): self.constant = constant super().__init__(list(e.items())) elif isinstance(e, Iterable): self.constant = constant super().__init__(e) elif isinstance(e, LpElement): self.constant = 0 super().__init__([(e, 1)]) else: self.constant = e super().__init__()
(self, e=None, constant=0, name=None)
38,474
pulp.pulp
__isub__
null
def __isub__(self, other): return (self).subInPlace(other)
(self, other)
38,475
pulp.pulp
__le__
null
def __le__(self, other): return LpConstraint(self - other, const.LpConstraintLE)
(self, other)
38,476
pulp.pulp
__mul__
null
def __mul__(self, other): e = self.emptyCopy() if isinstance(other, LpAffineExpression): e.constant = self.constant * other.constant if len(other): if len(self): raise TypeError("Non-constant expressions cannot be multiplied") else: c = self.constant if c != 0: for v, x in other.items(): e[v] = c * x else: c = other.constant if c != 0: for v, x in self.items(): e[v] = c * x elif isinstance(other, LpVariable): return self * LpAffineExpression(other) else: if other != 0: e.constant = self.constant * other for v, x in self.items(): e[v] = other * x return e
(self, other)
38,477
pulp.pulp
__neg__
null
def __neg__(self): e = self.emptyCopy() e.constant = -self.constant for v, x in self.items(): e[v] = -x return e
(self)
38,478
pulp.pulp
__pos__
null
def __pos__(self): return self
(self)
38,479
pulp.pulp
__radd__
null
def __radd__(self, other): return self.copy().addInPlace(other)
(self, other)
38,480
pulp.pulp
__rdiv__
null
def __rdiv__(self, other): e = self.emptyCopy() if len(self): raise TypeError( "Expressions cannot be divided by a non-constant expression" ) c = self.constant if isinstance(other, LpAffineExpression): e.constant = other.constant / c for v, x in other.items(): e[v] = x / c else: e.constant = other / c return e
(self, other)
38,481
pulp.pulp
__repr__
null
def __repr__(self): l = [str(self[v]) + "*" + str(v) for v in self.sorted_keys()] l.append(str(self.constant)) s = " + ".join(l) return s
(self)
38,482
pulp.pulp
__rmul__
null
def __rmul__(self, other): return self * other
(self, other)
38,483
pulp.pulp
__rsub__
null
def __rsub__(self, other): return (-self).addInPlace(other)
(self, other)