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from __future__ import annotations |
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|
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from sympy.core import Basic, S |
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from sympy.core.function import Lambda |
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from sympy.core.numbers import equal_valued |
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from sympy.printing.codeprinter import CodePrinter |
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from sympy.printing.precedence import precedence |
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from functools import reduce |
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|
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known_functions = { |
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'Abs': 'abs', |
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'sin': 'sin', |
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'cos': 'cos', |
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'tan': 'tan', |
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'acos': 'acos', |
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'asin': 'asin', |
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'atan': 'atan', |
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'atan2': 'atan', |
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'ceiling': 'ceil', |
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'floor': 'floor', |
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'sign': 'sign', |
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'exp': 'exp', |
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'log': 'log', |
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'add': 'add', |
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'sub': 'sub', |
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'mul': 'mul', |
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'pow': 'pow' |
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} |
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|
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class GLSLPrinter(CodePrinter): |
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""" |
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Rudimentary, generic GLSL printing tools. |
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|
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Additional settings: |
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'use_operators': Boolean (should the printer use operators for +,-,*, or functions?) |
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""" |
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_not_supported: set[Basic] = set() |
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printmethod = "_glsl" |
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language = "GLSL" |
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|
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_default_settings = { |
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'use_operators': True, |
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'zero': 0, |
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'mat_nested': False, |
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'mat_separator': ',\n', |
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'mat_transpose': False, |
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'array_type': 'float', |
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'glsl_types': True, |
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|
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'order': None, |
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'full_prec': 'auto', |
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'precision': 9, |
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'user_functions': {}, |
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'human': True, |
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'allow_unknown_functions': False, |
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'contract': True, |
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'error_on_reserved': False, |
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'reserved_word_suffix': '_', |
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} |
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|
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def __init__(self, settings={}): |
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CodePrinter.__init__(self, settings) |
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self.known_functions = dict(known_functions) |
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userfuncs = settings.get('user_functions', {}) |
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self.known_functions.update(userfuncs) |
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|
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def _rate_index_position(self, p): |
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return p*5 |
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|
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def _get_statement(self, codestring): |
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return "%s;" % codestring |
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|
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def _get_comment(self, text): |
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return "// {}".format(text) |
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|
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def _declare_number_const(self, name, value): |
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return "float {} = {};".format(name, value) |
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|
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def _format_code(self, lines): |
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return self.indent_code(lines) |
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|
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def indent_code(self, code): |
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"""Accepts a string of code or a list of code lines""" |
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|
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if isinstance(code, str): |
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code_lines = self.indent_code(code.splitlines(True)) |
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return ''.join(code_lines) |
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|
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tab = " " |
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inc_token = ('{', '(', '{\n', '(\n') |
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dec_token = ('}', ')') |
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|
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code = [line.lstrip(' \t') for line in code] |
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|
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increase = [int(any(map(line.endswith, inc_token))) for line in code] |
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decrease = [int(any(map(line.startswith, dec_token))) for line in code] |
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|
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pretty = [] |
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level = 0 |
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for n, line in enumerate(code): |
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if line in ('', '\n'): |
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pretty.append(line) |
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continue |
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level -= decrease[n] |
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pretty.append("%s%s" % (tab*level, line)) |
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level += increase[n] |
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return pretty |
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|
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def _print_MatrixBase(self, mat): |
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mat_separator = self._settings['mat_separator'] |
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mat_transpose = self._settings['mat_transpose'] |
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column_vector = (mat.rows == 1) if mat_transpose else (mat.cols == 1) |
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A = mat.transpose() if mat_transpose != column_vector else mat |
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|
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glsl_types = self._settings['glsl_types'] |
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array_type = self._settings['array_type'] |
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array_size = A.cols*A.rows |
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array_constructor = "{}[{}]".format(array_type, array_size) |
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|
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if A.cols == 1: |
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return self._print(A[0]); |
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if A.rows <= 4 and A.cols <= 4 and glsl_types: |
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if A.rows == 1: |
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return "vec{}{}".format( |
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A.cols, A.table(self,rowstart='(',rowend=')') |
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) |
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elif A.rows == A.cols: |
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return "mat{}({})".format( |
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A.rows, A.table(self,rowsep=', ', |
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rowstart='',rowend='') |
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) |
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else: |
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return "mat{}x{}({})".format( |
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A.cols, A.rows, |
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A.table(self,rowsep=', ', |
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rowstart='',rowend='') |
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) |
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elif S.One in A.shape: |
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return "{}({})".format( |
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array_constructor, |
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A.table(self,rowsep=mat_separator,rowstart='',rowend='') |
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) |
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elif not self._settings['mat_nested']: |
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return "{}(\n{}\n) /* a {}x{} matrix */".format( |
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array_constructor, |
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A.table(self,rowsep=mat_separator,rowstart='',rowend=''), |
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A.rows, A.cols |
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) |
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elif self._settings['mat_nested']: |
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return "{}[{}][{}](\n{}\n)".format( |
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array_type, A.rows, A.cols, |
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A.table(self,rowsep=mat_separator,rowstart='float[](',rowend=')') |
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) |
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|
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def _print_SparseRepMatrix(self, mat): |
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|
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return self._print_not_supported(mat) |
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|
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def _traverse_matrix_indices(self, mat): |
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mat_transpose = self._settings['mat_transpose'] |
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if mat_transpose: |
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rows,cols = mat.shape |
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else: |
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cols,rows = mat.shape |
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return ((i, j) for i in range(cols) for j in range(rows)) |
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|
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def _print_MatrixElement(self, expr): |
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|
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nest = self._settings['mat_nested']; |
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glsl_types = self._settings['glsl_types']; |
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mat_transpose = self._settings['mat_transpose']; |
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if mat_transpose: |
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cols,rows = expr.parent.shape |
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i,j = expr.j,expr.i |
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else: |
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rows,cols = expr.parent.shape |
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i,j = expr.i,expr.j |
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pnt = self._print(expr.parent) |
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if glsl_types and ((rows <= 4 and cols <=4) or nest): |
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return "{}[{}][{}]".format(pnt, i, j) |
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else: |
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return "{}[{}]".format(pnt, i + j*rows) |
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|
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def _print_list(self, expr): |
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l = ', '.join(self._print(item) for item in expr) |
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glsl_types = self._settings['glsl_types'] |
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array_type = self._settings['array_type'] |
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array_size = len(expr) |
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array_constructor = '{}[{}]'.format(array_type, array_size) |
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|
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if array_size <= 4 and glsl_types: |
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return 'vec{}({})'.format(array_size, l) |
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else: |
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return '{}({})'.format(array_constructor, l) |
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_print_tuple = _print_list |
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_print_Tuple = _print_list |
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|
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def _get_loop_opening_ending(self, indices): |
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open_lines = [] |
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close_lines = [] |
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loopstart = "for (int %(varble)s=%(start)s; %(varble)s<%(end)s; %(varble)s++){" |
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for i in indices: |
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open_lines.append(loopstart % { |
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'varble': self._print(i.label), |
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'start': self._print(i.lower), |
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'end': self._print(i.upper + 1)}) |
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close_lines.append("}") |
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return open_lines, close_lines |
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|
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def _print_Function_with_args(self, func, func_args): |
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if func in self.known_functions: |
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cond_func = self.known_functions[func] |
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func = None |
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if isinstance(cond_func, str): |
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func = cond_func |
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else: |
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for cond, func in cond_func: |
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if cond(func_args): |
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break |
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if func is not None: |
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try: |
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return func(*[self.parenthesize(item, 0) for item in func_args]) |
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except TypeError: |
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return '{}({})'.format(func, self.stringify(func_args, ", ")) |
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elif isinstance(func, Lambda): |
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|
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return self._print(func(*func_args)) |
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else: |
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return self._print_not_supported(func) |
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|
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def _print_Piecewise(self, expr): |
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from sympy.codegen.ast import Assignment |
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if expr.args[-1].cond != True: |
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raise ValueError("All Piecewise expressions must contain an " |
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"(expr, True) statement to be used as a default " |
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"condition. Without one, the generated " |
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"expression may not evaluate to anything under " |
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"some condition.") |
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lines = [] |
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if expr.has(Assignment): |
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for i, (e, c) in enumerate(expr.args): |
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if i == 0: |
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lines.append("if (%s) {" % self._print(c)) |
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elif i == len(expr.args) - 1 and c == True: |
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lines.append("else {") |
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else: |
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lines.append("else if (%s) {" % self._print(c)) |
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code0 = self._print(e) |
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lines.append(code0) |
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lines.append("}") |
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return "\n".join(lines) |
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else: |
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ecpairs = ["((%s) ? (\n%s\n)\n" % (self._print(c), |
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self._print(e)) |
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for e, c in expr.args[:-1]] |
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last_line = ": (\n%s\n)" % self._print(expr.args[-1].expr) |
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return ": ".join(ecpairs) + last_line + " ".join([")"*len(ecpairs)]) |
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def _print_Idx(self, expr): |
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return self._print(expr.label) |
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def _print_Indexed(self, expr): |
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|
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dims = expr.shape |
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elem = S.Zero |
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offset = S.One |
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for i in reversed(range(expr.rank)): |
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elem += expr.indices[i]*offset |
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offset *= dims[i] |
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return "{}[{}]".format( |
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self._print(expr.base.label), |
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self._print(elem) |
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) |
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def _print_Pow(self, expr): |
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PREC = precedence(expr) |
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if equal_valued(expr.exp, -1): |
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return '1.0/%s' % (self.parenthesize(expr.base, PREC)) |
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elif equal_valued(expr.exp, 0.5): |
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return 'sqrt(%s)' % self._print(expr.base) |
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else: |
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try: |
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e = self._print(float(expr.exp)) |
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except TypeError: |
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e = self._print(expr.exp) |
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return self._print_Function_with_args('pow', ( |
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self._print(expr.base), |
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e |
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)) |
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def _print_int(self, expr): |
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return str(float(expr)) |
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def _print_Rational(self, expr): |
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return "{}.0/{}.0".format(expr.p, expr.q) |
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def _print_Relational(self, expr): |
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lhs_code = self._print(expr.lhs) |
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rhs_code = self._print(expr.rhs) |
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op = expr.rel_op |
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return "{} {} {}".format(lhs_code, op, rhs_code) |
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def _print_Add(self, expr, order=None): |
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if self._settings['use_operators']: |
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return CodePrinter._print_Add(self, expr, order=order) |
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terms = expr.as_ordered_terms() |
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def partition(p,l): |
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return reduce(lambda x, y: (x[0]+[y], x[1]) if p(y) else (x[0], x[1]+[y]), l, ([], [])) |
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def add(a,b): |
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return self._print_Function_with_args('add', (a, b)) |
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neg, pos = partition(lambda arg: arg.could_extract_minus_sign(), terms) |
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if pos: |
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s = pos = reduce(lambda a,b: add(a,b), (self._print(t) for t in pos)) |
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else: |
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s = pos = self._print(self._settings['zero']) |
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if neg: |
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neg = reduce(lambda a,b: add(a,b), (self._print(-n) for n in neg)) |
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s = self._print_Function_with_args('sub', (pos,neg)) |
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return s |
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def _print_Mul(self, expr, **kwargs): |
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if self._settings['use_operators']: |
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return CodePrinter._print_Mul(self, expr, **kwargs) |
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terms = expr.as_ordered_factors() |
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def mul(a,b): |
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|
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return self._print_Function_with_args('mul', (a,b)) |
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s = reduce(lambda a,b: mul(a,b), (self._print(t) for t in terms)) |
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return s |
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def glsl_code(expr,assign_to=None,**settings): |
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"""Converts an expr to a string of GLSL code |
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|
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Parameters |
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========== |
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|
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expr : Expr |
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A SymPy expression to be converted. |
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assign_to : optional |
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When given, the argument is used for naming the variable or variables |
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to which the expression is assigned. Can be a string, ``Symbol``, |
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``MatrixSymbol`` or ``Indexed`` type object. In cases where ``expr`` |
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would be printed as an array, a list of string or ``Symbol`` objects |
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can also be passed. |
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|
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This is helpful in case of line-wrapping, or for expressions that |
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generate multi-line statements. It can also be used to spread an array-like |
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expression into multiple assignments. |
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use_operators: bool, optional |
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If set to False, then *,/,+,- operators will be replaced with functions |
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mul, add, and sub, which must be implemented by the user, e.g. for |
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implementing non-standard rings or emulated quad/octal precision. |
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[default=True] |
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glsl_types: bool, optional |
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Set this argument to ``False`` in order to avoid using the ``vec`` and ``mat`` |
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types. The printer will instead use arrays (or nested arrays). |
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[default=True] |
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mat_nested: bool, optional |
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GLSL version 4.3 and above support nested arrays (arrays of arrays). Set this to ``True`` |
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to render matrices as nested arrays. |
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[default=False] |
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mat_separator: str, optional |
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By default, matrices are rendered with newlines using this separator, |
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making them easier to read, but less compact. By removing the newline |
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this option can be used to make them more vertically compact. |
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[default=',\n'] |
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mat_transpose: bool, optional |
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GLSL's matrix multiplication implementation assumes column-major indexing. |
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By default, this printer ignores that convention. Setting this option to |
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``True`` transposes all matrix output. |
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[default=False] |
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array_type: str, optional |
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The GLSL array constructor type. |
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[default='float'] |
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precision : integer, optional |
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The precision for numbers such as pi [default=15]. |
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user_functions : dict, optional |
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A dictionary where keys are ``FunctionClass`` instances and values are |
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their string representations. Alternatively, the dictionary value can |
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be a list of tuples i.e. [(argument_test, js_function_string)]. See |
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below for examples. |
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human : bool, optional |
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If True, the result is a single string that may contain some constant |
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declarations for the number symbols. If False, the same information is |
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returned in a tuple of (symbols_to_declare, not_supported_functions, |
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code_text). [default=True]. |
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contract: bool, optional |
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If True, ``Indexed`` instances are assumed to obey tensor contraction |
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rules and the corresponding nested loops over indices are generated. |
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Setting contract=False will not generate loops, instead the user is |
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responsible to provide values for the indices in the code. |
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[default=True]. |
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|
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Examples |
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======== |
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|
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>>> from sympy import glsl_code, symbols, Rational, sin, ceiling, Abs |
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>>> x, tau = symbols("x, tau") |
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>>> glsl_code((2*tau)**Rational(7, 2)) |
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'8*sqrt(2)*pow(tau, 3.5)' |
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>>> glsl_code(sin(x), assign_to="float y") |
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'float y = sin(x);' |
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|
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Various GLSL types are supported: |
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>>> from sympy import Matrix, glsl_code |
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>>> glsl_code(Matrix([1,2,3])) |
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'vec3(1, 2, 3)' |
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|
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>>> glsl_code(Matrix([[1, 2],[3, 4]])) |
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'mat2(1, 2, 3, 4)' |
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|
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Pass ``mat_transpose = True`` to switch to column-major indexing: |
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>>> glsl_code(Matrix([[1, 2],[3, 4]]), mat_transpose = True) |
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'mat2(1, 3, 2, 4)' |
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|
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By default, larger matrices get collapsed into float arrays: |
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>>> print(glsl_code( Matrix([[1,2,3,4,5],[6,7,8,9,10]]) )) |
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float[10]( |
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1, 2, 3, 4, 5, |
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6, 7, 8, 9, 10 |
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) /* a 2x5 matrix */ |
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|
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The type of array constructor used to print GLSL arrays can be controlled |
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via the ``array_type`` parameter: |
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>>> glsl_code(Matrix([1,2,3,4,5]), array_type='int') |
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'int[5](1, 2, 3, 4, 5)' |
|
|
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Passing a list of strings or ``symbols`` to the ``assign_to`` parameter will yield |
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a multi-line assignment for each item in an array-like expression: |
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>>> x_struct_members = symbols('x.a x.b x.c x.d') |
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>>> print(glsl_code(Matrix([1,2,3,4]), assign_to=x_struct_members)) |
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x.a = 1; |
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x.b = 2; |
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x.c = 3; |
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x.d = 4; |
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|
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This could be useful in cases where it's desirable to modify members of a |
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GLSL ``Struct``. It could also be used to spread items from an array-like |
|
expression into various miscellaneous assignments: |
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>>> misc_assignments = ('x[0]', 'x[1]', 'float y', 'float z') |
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>>> print(glsl_code(Matrix([1,2,3,4]), assign_to=misc_assignments)) |
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x[0] = 1; |
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x[1] = 2; |
|
float y = 3; |
|
float z = 4; |
|
|
|
Passing ``mat_nested = True`` instead prints out nested float arrays, which are |
|
supported in GLSL 4.3 and above. |
|
>>> mat = Matrix([ |
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... [ 0, 1, 2], |
|
... [ 3, 4, 5], |
|
... [ 6, 7, 8], |
|
... [ 9, 10, 11], |
|
... [12, 13, 14]]) |
|
>>> print(glsl_code( mat, mat_nested = True )) |
|
float[5][3]( |
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float[]( 0, 1, 2), |
|
float[]( 3, 4, 5), |
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float[]( 6, 7, 8), |
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float[]( 9, 10, 11), |
|
float[](12, 13, 14) |
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) |
|
|
|
|
|
|
|
Custom printing can be defined for certain types by passing a dictionary of |
|
"type" : "function" to the ``user_functions`` kwarg. Alternatively, the |
|
dictionary value can be a list of tuples i.e. [(argument_test, |
|
js_function_string)]. |
|
|
|
>>> custom_functions = { |
|
... "ceiling": "CEIL", |
|
... "Abs": [(lambda x: not x.is_integer, "fabs"), |
|
... (lambda x: x.is_integer, "ABS")] |
|
... } |
|
>>> glsl_code(Abs(x) + ceiling(x), user_functions=custom_functions) |
|
'fabs(x) + CEIL(x)' |
|
|
|
If further control is needed, addition, subtraction, multiplication and |
|
division operators can be replaced with ``add``, ``sub``, and ``mul`` |
|
functions. This is done by passing ``use_operators = False``: |
|
|
|
>>> x,y,z = symbols('x,y,z') |
|
>>> glsl_code(x*(y+z), use_operators = False) |
|
'mul(x, add(y, z))' |
|
>>> glsl_code(x*(y+z*(x-y)**z), use_operators = False) |
|
'mul(x, add(y, mul(z, pow(sub(x, y), z))))' |
|
|
|
``Piecewise`` expressions are converted into conditionals. If an |
|
``assign_to`` variable is provided an if statement is created, otherwise |
|
the ternary operator is used. Note that if the ``Piecewise`` lacks a |
|
default term, represented by ``(expr, True)`` then an error will be thrown. |
|
This is to prevent generating an expression that may not evaluate to |
|
anything. |
|
|
|
>>> from sympy import Piecewise |
|
>>> expr = Piecewise((x + 1, x > 0), (x, True)) |
|
>>> print(glsl_code(expr, tau)) |
|
if (x > 0) { |
|
tau = x + 1; |
|
} |
|
else { |
|
tau = x; |
|
} |
|
|
|
Support for loops is provided through ``Indexed`` types. With |
|
``contract=True`` these expressions will be turned into loops, whereas |
|
``contract=False`` will just print the assignment expression that should be |
|
looped over: |
|
|
|
>>> from sympy import Eq, IndexedBase, Idx |
|
>>> len_y = 5 |
|
>>> y = IndexedBase('y', shape=(len_y,)) |
|
>>> t = IndexedBase('t', shape=(len_y,)) |
|
>>> Dy = IndexedBase('Dy', shape=(len_y-1,)) |
|
>>> i = Idx('i', len_y-1) |
|
>>> e=Eq(Dy[i], (y[i+1]-y[i])/(t[i+1]-t[i])) |
|
>>> glsl_code(e.rhs, assign_to=e.lhs, contract=False) |
|
'Dy[i] = (y[i + 1] - y[i])/(t[i + 1] - t[i]);' |
|
|
|
>>> from sympy import Matrix, MatrixSymbol |
|
>>> mat = Matrix([x**2, Piecewise((x + 1, x > 0), (x, True)), sin(x)]) |
|
>>> A = MatrixSymbol('A', 3, 1) |
|
>>> print(glsl_code(mat, A)) |
|
A[0][0] = pow(x, 2.0); |
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if (x > 0) { |
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A[1][0] = x + 1; |
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} |
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else { |
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A[1][0] = x; |
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} |
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A[2][0] = sin(x); |
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""" |
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return GLSLPrinter(settings).doprint(expr,assign_to) |
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|
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def print_glsl(expr, **settings): |
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"""Prints the GLSL representation of the given expression. |
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|
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See GLSLPrinter init function for settings. |
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""" |
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print(glsl_code(expr, **settings)) |
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|