shap_plots.py

import warnings
import iml
import numpy as np
from iml import Instance, Model
from iml.datatypes import DenseData
from iml.explanations import AdditiveExplanation
from iml.links import IdentityLink
from scipy.stats import gaussian_kde
import matplotlib
try:
    import matplotlib.pyplot as pl
    from matplotlib.colors import LinearSegmentedColormap
    from matplotlib.ticker import MaxNLocator

    cdict1 = {
        'red': ((0.0, 0.11764705882352941, 0.11764705882352941),
                (1.0, 0.9607843137254902, 0.9607843137254902)),

        'green': ((0.0, 0.5333333333333333, 0.5333333333333333),
                  (1.0, 0.15294117647058825, 0.15294117647058825)),

        'blue': ((0.0, 0.8980392156862745, 0.8980392156862745),
                 (1.0, 0.3411764705882353, 0.3411764705882353)),

        'alpha': ((0.0, 1, 1),
                  (0.5, 0.3, 0.3),
                  (1.0, 1, 1))
    }  # #1E88E5 -> #ff0052
    red_blue = LinearSegmentedColormap('RedBlue', cdict1)

    cdict1 = {
        'red': ((0.0, 0.11764705882352941, 0.11764705882352941),
                (1.0, 0.9607843137254902, 0.9607843137254902)),

        'green': ((0.0, 0.5333333333333333, 0.5333333333333333),
                  (1.0, 0.15294117647058825, 0.15294117647058825)),

        'blue': ((0.0, 0.8980392156862745, 0.8980392156862745),
                 (1.0, 0.3411764705882353, 0.3411764705882353)),

        'alpha': ((0.0, 1, 1),
                  (0.5, 1, 1),
                  (1.0, 1, 1))
    }  # #1E88E5 -> #ff0052
    red_blue_solid = LinearSegmentedColormap('RedBlue', cdict1)
except ImportError:
    pass

labels = {
    'MAIN_EFFECT': "SHAP main effect value for\n%s",
    'INTERACTION_VALUE': "SHAP interaction value",
    'INTERACTION_EFFECT': "SHAP interaction value for\n%s and %s",
    'VALUE': "SHAP value (impact on model output)",
    'VALUE_FOR': "SHAP value for\n%s",
    'PLOT_FOR': "SHAP plot for %s",
    'FEATURE': "Feature %s",
    'FEATURE_VALUE': "Feature value",
    'FEATURE_VALUE_LOW': "Low",
    'FEATURE_VALUE_HIGH': "High",
    'JOINT_VALUE': "Joint SHAP value"
}

def shap_summary_plot(shap_values, features=None, feature_names=None, max_display=None, plot_type="dot",
                 color=None, axis_color="#333333", title=None, alpha=1, show=True, sort=True,
                 color_bar=True, auto_size_plot=True, layered_violin_max_num_bins=20):
    """Create a SHAP summary plot, colored by feature values when they are provided.

    Parameters
    ----------
    shap_values : numpy.array
        Matrix of SHAP values (# samples x # features)

    features : numpy.array or pandas.DataFrame or list
        Matrix of feature values (# samples x # features) or a feature_names list as shorthand

    feature_names : list
        Names of the features (length # features)

    max_display : int
        How many top features to include in the plot (default is 20, or 7 for interaction plots)

    plot_type : "dot" (default) or "violin"
        What type of summary plot to produce
    """

    assert len(shap_values.shape) != 1, "Summary plots need a matrix of shap_values, not a vector."

    # default color:
    if color is None:
        color = "coolwarm" if plot_type == 'layered_violin' else "#ff0052"

    # convert from a DataFrame or other types
    if str(type(features)) == "<class 'pandas.core.frame.DataFrame'>":
        if feature_names is None:
            feature_names = features.columns
        features = features.values
    elif str(type(features)) == "<class 'list'>":
        if feature_names is None:
            feature_names = features
        features = None
    elif (features is not None) and len(features.shape) == 1 and feature_names is None:
        feature_names = features
        features = None

    if feature_names is None:
        feature_names = [labels['FEATURE'] % str(i) for i in range(shap_values.shape[1] - 1)]

    mpl_fig = pl.figure(figsize=(1.5 * max_display + 1, 1 * max_display + 1))

    # plotting SHAP interaction values
    if len(shap_values.shape) == 3:
        if max_display is None:
            max_display = 7
        else:
            max_display = min(len(feature_names), max_display)

        sort_inds = np.argsort(-np.abs(shap_values[:, :-1, :-1].sum(1)).sum(0))

        # get plotting limits
        delta = 1.0 / (shap_values.shape[1] ** 2)
        slow = np.nanpercentile(shap_values, delta)
        shigh = np.nanpercentile(shap_values, 100 - delta)
        v = max(abs(slow), abs(shigh))
        slow = -0.2
        shigh = 0.2

        # mpl_fig = pl.figure(figsize=(1.5 * max_display + 1, 1 * max_display + 1))
        ax = mpl_fig.subplot(1, max_display, 1)
        proj_shap_values = shap_values[:, sort_inds[0], np.hstack((sort_inds, len(sort_inds)))]
        proj_shap_values[:, 1:] *= 2  # because off diag effects are split in half
        shap_summary_plot(
            proj_shap_values, features[:, sort_inds],
            feature_names=feature_names[sort_inds],
            sort=False, show=False, color_bar=False,
            auto_size_plot=False,
            max_display=max_display
        )
        pl.xlim((slow, shigh))
        pl.xlabel("")
        title_length_limit = 11
        pl.title(shorten_text(feature_names[sort_inds[0]], title_length_limit))
        for i in range(1, max_display):
            ind = sort_inds[i]
            pl.subplot(1, max_display, i + 1)
            proj_shap_values = shap_values[:, ind, np.hstack((sort_inds, len(sort_inds)))]
            proj_shap_values *= 2
            proj_shap_values[:, i] /= 2  # because only off diag effects are split in half
            shap_summary_plot(
                proj_shap_values, features[:, sort_inds],
                sort=False,
                feature_names=["" for i in range(features.shape[1])],
                show=False,
                color_bar=False,
                auto_size_plot=False,
                max_display=max_display
            )
            pl.xlim((slow, shigh))
            pl.xlabel("")
            if i == max_display // 2:
                pl.xlabel(labels['INTERACTION_VALUE'])
            pl.title(shorten_text(feature_names[ind], title_length_limit))
        pl.tight_layout(pad=0, w_pad=0, h_pad=0.0)
        pl.subplots_adjust(hspace=0, wspace=0.1)
        # if show:
        # #     pl.show()
        return mpl_fig

    if max_display is None:
        max_display = 20

    if sort:
        # order features by the sum of their effect magnitudes
        feature_order = np.argsort(np.sum(np.abs(shap_values), axis=0)[:-1])
        feature_order = feature_order[-min(max_display, len(feature_order)):]
    else:
        feature_order = np.flip(np.arange(min(max_display, shap_values.shape[1] - 1)), 0)

    row_height = 0.4
    if auto_size_plot:
        pl.gcf().set_size_inches(8, len(feature_order) * row_height + 1.5)
    pl.axvline(x=0, color="#999999", zorder=-1)

    if plot_type == "dot":
        for pos, i in enumerate(feature_order):
            pl.axhline(y=pos, color="#cccccc", lw=0.5, dashes=(1, 5), zorder=-1)
            shaps = shap_values[:, i]
            values = None if features is None else features[:, i]
            inds = np.arange(len(shaps))
            np.random.shuffle(inds)
            if values is not None:
                values = values[inds]
            shaps = shaps[inds]
            colored_feature = True
            try:
                values = np.array(values, dtype=np.float64)  # make sure this can be numeric
            except:
                colored_feature = False
            N = len(shaps)
            # hspacing = (np.max(shaps) - np.min(shaps)) / 200
            # curr_bin = []
            nbins = 100
            quant = np.round(nbins * (shaps - np.min(shaps)) / (np.max(shaps) - np.min(shaps) + 1e-8))
            inds = np.argsort(quant + np.random.randn(N) * 1e-6)
            layer = 0
            last_bin = -1
            ys = np.zeros(N)
            for ind in inds:
                if quant[ind] != last_bin:
                    layer = 0
                ys[ind] = np.ceil(layer / 2) * ((layer % 2) * 2 - 1)
                layer += 1
                last_bin = quant[ind]
            ys *= 0.9 * (row_height / np.max(ys + 1))

            if features is not None and colored_feature:
                # trim the color range, but prevent the color range from collapsing
                vmin = np.nanpercentile(values, 5)
                vmax = np.nanpercentile(values, 95)
                if vmin == vmax:
                    vmin = np.nanpercentile(values, 1)
                    vmax = np.nanpercentile(values, 99)
                    if vmin == vmax:
                        vmin = np.min(values)
                        vmax = np.max(values)

                assert features.shape[0] == len(shaps), "Feature and SHAP matrices must have the same number of rows!"
                nan_mask = np.isnan(values)
                pl.scatter(shaps[nan_mask], pos + ys[nan_mask], color="#777777", vmin=vmin,
                           vmax=vmax, s=16, alpha=alpha, linewidth=0,
                           zorder=3, rasterized=len(shaps) > 500)
                pl.scatter(shaps[np.invert(nan_mask)], pos + ys[np.invert(nan_mask)],
                           cmap=red_blue, vmin=vmin, vmax=vmax, s=16,
                           c=values[np.invert(nan_mask)], alpha=alpha, linewidth=0,
                           zorder=3, rasterized=len(shaps) > 500)
            else:

                pl.scatter(shaps, pos + ys, s=16, alpha=alpha, linewidth=0, zorder=3,
                           color=color if colored_feature else "#777777", rasterized=len(shaps) > 500)

    elif plot_type == "violin":
        for pos, i in enumerate(feature_order):
            pl.axhline(y=pos, color="#cccccc", lw=0.5, dashes=(1, 5), zorder=-1)

        if features is not None:
            global_low = np.nanpercentile(shap_values[:, :len(feature_names)].flatten(), 1)
            global_high = np.nanpercentile(shap_values[:, :len(feature_names)].flatten(), 99)
            for pos, i in enumerate(feature_order):
                shaps = shap_values[:, i]
                shap_min, shap_max = np.min(shaps), np.max(shaps)
                rng = shap_max - shap_min
                xs = np.linspace(np.min(shaps) - rng * 0.2, np.max(shaps) + rng * 0.2, 100)
                if np.std(shaps) < (global_high - global_low) / 100:
                    ds = gaussian_kde(shaps + np.random.randn(len(shaps)) * (global_high - global_low) / 100)(xs)
                else:
                    ds = gaussian_kde(shaps)(xs)
                ds /= np.max(ds) * 3

                values = features[:, i]
                window_size = max(10, len(values) // 20)
                smooth_values = np.zeros(len(xs) - 1)
                sort_inds = np.argsort(shaps)
                trailing_pos = 0
                leading_pos = 0
                running_sum = 0
                back_fill = 0
                for j in range(len(xs) - 1):

                    while leading_pos < len(shaps) and xs[j] >= shaps[sort_inds[leading_pos]]:
                        running_sum += values[sort_inds[leading_pos]]
                        leading_pos += 1
                        if leading_pos - trailing_pos > 20:
                            running_sum -= values[sort_inds[trailing_pos]]
                            trailing_pos += 1
                    if leading_pos - trailing_pos > 0:
                        smooth_values[j] = running_sum / (leading_pos - trailing_pos)
                        for k in range(back_fill):
                            smooth_values[j - k - 1] = smooth_values[j]
                    else:
                        back_fill += 1

                vmin = np.nanpercentile(values, 5)
                vmax = np.nanpercentile(values, 95)
                if vmin == vmax:
                    vmin = np.nanpercentile(values, 1)
                    vmax = np.nanpercentile(values, 99)
                    if vmin == vmax:
                        vmin = np.min(values)
                        vmax = np.max(values)
                pl.scatter(shaps, np.ones(shap_values.shape[0]) * pos, s=9, cmap=red_blue_solid, vmin=vmin, vmax=vmax,
                           c=values, alpha=alpha, linewidth=0, zorder=1)
                # smooth_values -= nxp.nanpercentile(smooth_values, 5)
                # smooth_values /= np.nanpercentile(smooth_values, 95)
                smooth_values -= vmin
                if vmax - vmin > 0:
                    smooth_values /= vmax - vmin
                for i in range(len(xs) - 1):
                    if ds[i] > 0.05 or ds[i + 1] > 0.05:
                        pl.fill_between([xs[i], xs[i + 1]], [pos + ds[i], pos + ds[i + 1]],
                                        [pos - ds[i], pos - ds[i + 1]], color=red_blue_solid(smooth_values[i]),
                                        zorder=2)

        else:
            parts = pl.violinplot(shap_values[:, feature_order], range(len(feature_order)), points=200, vert=False,
                                  widths=0.7,
                                  showmeans=False, showextrema=False, showmedians=False)

            for pc in parts['bodies']:
                pc.set_facecolor(color)
                pc.set_edgecolor('none')
                pc.set_alpha(alpha)

    elif plot_type == "layered_violin":  # courtesy of @kodonnell
        num_x_points = 200
        bins = np.linspace(0, features.shape[0], layered_violin_max_num_bins + 1).round(0).astype(
            'int')  # the indices of the feature data corresponding to each bin
        shap_min, shap_max = np.min(shap_values[:, :-1]), np.max(shap_values[:, :-1])
        x_points = np.linspace(shap_min, shap_max, num_x_points)

        # loop through each feature and plot:
        for pos, ind in enumerate(feature_order):
            # decide how to handle: if #unique < layered_violin_max_num_bins then split by unique value, otherwise use bins/percentiles.
            # to keep simpler code, in the case of uniques, we just adjust the bins to align with the unique counts.
            feature = features[:, ind]
            unique, counts = np.unique(feature, return_counts=True)
            if unique.shape[0] <= layered_violin_max_num_bins:
                order = np.argsort(unique)
                thesebins = np.cumsum(counts[order])
                thesebins = np.insert(thesebins, 0, 0)
            else:
                thesebins = bins
            nbins = thesebins.shape[0] - 1
            # order the feature data so we can apply percentiling
            order = np.argsort(feature)
            # x axis is located at y0 = pos, with pos being there for offset
            y0 = np.ones(num_x_points) * pos
            # calculate kdes:
            ys = np.zeros((nbins, num_x_points))
            for i in range(nbins):
                # get shap values in this bin:
                shaps = shap_values[order[thesebins[i]:thesebins[i + 1]], ind]
                # if there's only one element, then we can't
                if shaps.shape[0] == 1:
                    warnings.warn(
                        "not enough data in bin #%d for feature %s, so it'll be ignored. Try increasing the number of records to plot."
                        % (i, feature_names[ind]))
                    # to ignore it, just set it to the previous y-values (so the area between them will be zero). Not ys is already 0, so there's
                    # nothing to do if i == 0
                    if i > 0:
                        ys[i, :] = ys[i - 1, :]
                    continue
                # save kde of them: note that we add a tiny bit of gaussian noise to avoid singular matrix errors
                ys[i, :] = gaussian_kde(shaps + np.random.normal(loc=0, scale=0.001, size=shaps.shape[0]))(x_points)
                # scale it up so that the 'size' of each y represents the size of the bin. For continuous data this will
                # do nothing, but when we've gone with the unqique option, this will matter - e.g. if 99% are male and 1%
                # female, we want the 1% to appear a lot smaller.
                size = thesebins[i + 1] - thesebins[i]
                bin_size_if_even = features.shape[0] / nbins
                relative_bin_size = size / bin_size_if_even
                ys[i, :] *= relative_bin_size
            # now plot 'em. We don't plot the individual strips, as this can leave whitespace between them.
            # instead, we plot the full kde, then remove outer strip and plot over it, etc., to ensure no
            # whitespace
            ys = np.cumsum(ys, axis=0)
            width = 0.8
            scale = ys.max() * 2 / width  # 2 is here as we plot both sides of x axis
            for i in range(nbins - 1, -1, -1):
                y = ys[i, :] / scale
                c = pl.get_cmap(color)(i / (
                        nbins - 1)) if color in pl.cm.datad else color  # if color is a cmap, use it, otherwise use a color
                pl.fill_between(x_points, pos - y, pos + y, facecolor=c)
        pl.xlim(shap_min, shap_max)

    # draw the color bar
    if color_bar and features is not None and (plot_type != "layered_violin" or color in pl.cm.datad):
            import matplotlib.cm as cm
            m = cm.ScalarMappable(cmap=red_blue_solid if plot_type != "layered_violin" else pl.get_cmap(color))
            m.set_array([0, 1])
            cb = pl.colorbar(m, ticks=[0, 1], aspect=1000)
            cb.set_ticklabels([labels['FEATURE_VALUE_LOW'], labels['FEATURE_VALUE_HIGH']])
            cb.set_label(labels['FEATURE_VALUE'], size=12, labelpad=0)
            cb.ax.tick_params(labelsize=11, length=0)
            cb.set_alpha(1)
            cb.outline.set_visible(False)
            bbox = cb.ax.get_window_extent().transformed(pl.gcf().dpi_scale_trans.inverted())
            cb.ax.set_aspect((bbox.height - 0.9) * 20)
        # cb.draw_all()

    pl.gca().xaxis.set_ticks_position('bottom')
    pl.gca().yaxis.set_ticks_position('none')
    pl.gca().spines['right'].set_visible(False)
    pl.gca().spines['top'].set_visible(False)
    pl.gca().spines['left'].set_visible(False)
    pl.gca().tick_params(color=axis_color, labelcolor=axis_color)
    pl.yticks(range(len(feature_order)), [feature_names[i] for i in feature_order], fontsize=13)
    pl.gca().tick_params('y', length=20, width=0.5, which='major')
    pl.gca().tick_params('x', labelsize=11)
    pl.ylim(-1, len(feature_order))
    pl.xlabel(labels['VALUE'], fontsize=13)
    pl.tight_layout()
    # if show:
    #     pl.show()
    return mpl_fig






def approx_interactions(index, shap_values, X):
    """ Order other features by how much interaction they seem to have with the feature at the given index.

    This just bins the SHAP values for a feature along that feature's value. For true Shapley interaction
    index values for SHAP see the interaction_contribs option implemented in XGBoost.
    """

    if X.shape[0] > 10000:
        a = np.arange(X.shape[0])
        np.random.shuffle(a)
        inds = a[:10000]
    else:
        inds = np.arange(X.shape[0])

    x = X[inds, index]
    srt = np.argsort(x)
    shap_ref = shap_values[inds, index]
    shap_ref = shap_ref[srt]
    inc = max(min(int(len(x) / 10.0), 50), 1)
    interactions = []
    for i in range(X.shape[1]):
        val_other = X[inds, i][srt].astype(np.float)
        v = 0.0
        if not (i == index or np.sum(np.abs(val_other)) < 1e-8):
            for j in range(0, len(x), inc):
                if np.std(val_other[j:j + inc]) > 0 and np.std(shap_ref[j:j + inc]) > 0:
                    v += abs(np.corrcoef(shap_ref[j:j + inc], val_other[j:j + inc])[0, 1])
        interactions.append(v)

    return np.argsort(-np.abs(interactions))







def shap_dependence_plot(ind, shap_values, features, feature_names=None, display_features=None,
                    interaction_index="auto", color="#1E88E5", axis_color="#333333",
                    dot_size=16, alpha=1, title=None, show=True):
    """
    Create a SHAP dependence plot, colored by an interaction feature.

    Parameters
    ----------
    ind : int
        Index of the feature to plot.

    shap_values : numpy.array
        Matrix of SHAP values (# samples x # features)

    features : numpy.array or pandas.DataFrame
        Matrix of feature values (# samples x # features)

    feature_names : list
        Names of the features (length # features)

    display_features : numpy.array or pandas.DataFrame
        Matrix of feature values for visual display (such as strings instead of coded values)

    interaction_index : "auto", None, or int
        The index of the feature used to color the plot.
    """

    # convert from DataFrames if we got any
    if str(type(features)).endswith("'pandas.core.frame.DataFrame'>"):
        if feature_names is None:
            feature_names = features.columns
        features = features.values
    if str(type(display_features)).endswith("'pandas.core.frame.DataFrame'>"):
        if feature_names is None:
            feature_names = display_features.columns
        display_features = display_features.values
    elif display_features is None:
        display_features = features

    if feature_names is None:
        feature_names = [labels['FEATURE'] % str(i) for i in range(shap_values.shape[1] - 1)]

    # allow vectors to be passed
    if len(shap_values.shape) == 1:
        shap_values = np.reshape(shap_values, len(shap_values), 1)
    if len(features.shape) == 1:
        features = np.reshape(features, len(features), 1)

    def convert_name(ind):
        if type(ind) == str:
            nzinds = np.where(feature_names == ind)[0]
            if len(nzinds) == 0:
                print("Could not find feature named: " + ind)
                return None
            else:
                return nzinds[0]
        else:
            return ind

    ind = convert_name(ind)

    mpl_fig = pl.gcf()
    ax = mpl_fig.gca()

    # plotting SHAP interaction values
    if len(shap_values.shape) == 3 and len(ind) == 2:
        ind1 = convert_name(ind[0])
        ind2 = convert_name(ind[1])
        if ind1 == ind2:
            proj_shap_values = shap_values[:, ind2, :]
        else:
            proj_shap_values = shap_values[:, ind2, :] * 2  # off-diag values are split in half

        # TODO: remove recursion; generally the functions should be shorter for more maintainable code
        return shap_dependence_plot(
            ind1, proj_shap_values, features, feature_names=feature_names,
            interaction_index=ind2, display_features=display_features, show=False
        )

        assert shap_values.shape[0] == features.shape[0], \
            "'shap_values' and 'features' values must have the same number of rows!"
        assert shap_values.shape[1] == features.shape[1], \
            "'shap_values' must have the same number of columns as 'features'!"

        # get both the raw and display feature values
        xv = features[:, ind]
        xd = display_features[:, ind]
        s = shap_values[:, ind]
        if type(xd[0]) == str:
            name_map = {}
            for i in range(len(xv)):
                name_map[xd[i]] = xv[i]
            xnames = list(name_map.keys())

        # allow a single feature name to be passed alone
        if type(feature_names) == str:
            feature_names = [feature_names]
        name = feature_names[ind]

        # guess what other feature as the stongest interaction with the plotted feature
        if interaction_index == "auto":
            interaction_index = approx_interactions(ind, shap_values, features)[0]
        interaction_index = convert_name(interaction_index)
        categorical_interaction = False

        # get both the raw and display color values
        if interaction_index is not None:
            cv = features[:, interaction_index]
            cd = display_features[:, interaction_index]
            clow = np.nanpercentile(features[:, interaction_index].astype(np.float), 5)
            chigh = np.nanpercentile(features[:, interaction_index].astype(np.float), 95)
            if type(cd[0]) == str:
                cname_map = {}
                for i in range(len(cv)):
                    cname_map[cd[i]] = cv[i]
                cnames = list(cname_map.keys())
                categorical_interaction = True
            elif clow % 1 == 0 and chigh % 1 == 0 and len(set(features[:, interaction_index])) < 50:
                categorical_interaction = True

        # discritize colors for categorical features
        color_norm = None
        if categorical_interaction and clow != chigh:
            bounds = np.linspace(clow, chigh, chigh - clow + 2)
            color_norm = matplotlib.colors.BoundaryNorm(bounds, red_blue.N)

        # the actual scatter plot, TODO: adapt the dot_size to the number of data points?
        if interaction_index is not None:
            pl.scatter(xv, s, s=dot_size, linewidth=0, c=features[:, interaction_index], cmap=red_blue,
                       alpha=alpha, vmin=clow, vmax=chigh, norm=color_norm, rasterized=len(xv) > 500)
        else:
            pl.scatter(xv, s, s=dot_size, linewidth=0, color="#1E88E5",
                       alpha=alpha, rasterized=len(xv) > 500)

        if interaction_index != ind and interaction_index is not None:
            # draw the color bar
            if type(cd[0]) == str:
                tick_positions = [cname_map[n] for n in cnames]
                if len(tick_positions) == 2:
                    tick_positions[0] -= 0.25
                    tick_positions[1] += 0.25
                cb = pl.colorbar(ticks=tick_positions)
                cb.set_ticklabels(cnames)
            else:
                cb = pl.colorbar()

            cb.set_label(feature_names[interaction_index], size=13)
            cb.ax.tick_params(labelsize=11)
            if categorical_interaction:
                cb.ax.tick_params(length=0)
            cb.set_alpha(1)
            cb.outline.set_visible(False)
            bbox = cb.ax.get_window_extent().transformed(pl.gcf().dpi_scale_trans.inverted())
            cb.ax.set_aspect((bbox.height - 0.7) * 20)

        # make the plot more readable
        if interaction_index != ind:
            pl.gcf().set_size_inches(7.5, 5)
        else:
            pl.gcf().set_size_inches(6, 5)
        # pl.xlabel(name, color=axis_color, fontsize=13)
        # pl.ylabel(labels['VALUE_FOR'] % name, color=axis_color, fontsize=13)
        if title is not None:
            pl.title(title, color=axis_color, fontsize=13)
        pl.gca().xaxis.set_ticks_position('bottom')
        pl.gca().yaxis.set_ticks_position('left')
        pl.gca().spines['right'].set_visible(False)
        pl.gca().spines['top'].set_visible(False)
        pl.gca().tick_params(color=axis_color, labelcolor=axis_color, labelsize=11)
        for spine in pl.gca().spines.values():
            spine.set_edgecolor(axis_color)
        if type(xd[0]) == str:
            pl.xticks([name_map[n] for n in xnames], xnames, rotation='vertical', fontsize=11)
        # if show:
            # pl.show()


        if ind1 == ind2:
            pl.ylabel(labels['MAIN_EFFECT'] % feature_names[ind1])
        else:
            pl.ylabel(labels['INTERACTION_EFFECT'] % (feature_names[ind1], feature_names[ind2]))

        return mpl_fig, interaction_index


        # # if show:
        # #     pl.show()
        # return
        # return mpl_fig

    # assert shap_values.shape[0] == features.shape[0], "'shap_values' and 'features' values must have the same number of rows!"
    # assert shap_values.shape[1] == features.shape[1] + 1, "'shap_values' must have one more column than 'features'!"

    # get both the raw and display feature values
    xv = features[:, ind]
    xd = display_features[:, ind]
    s = shap_values[:, ind]
    if type(xd[0]) == str:
        name_map = {}
        for i in range(len(xv)):
            name_map[xd[i]] = xv[i]
        xnames = list(name_map.keys())

    # allow a single feature name to be passed alone
    if type(feature_names) == str:
        feature_names = [feature_names]
    name = feature_names[ind]

    # guess what other feature as the stongest interaction with the plotted feature
    if interaction_index == "auto":
        interaction_index = approx_interactions(ind, shap_values, features)[0]
    interaction_index = convert_name(interaction_index)
    categorical_interaction = False

    # get both the raw and display color values
    if interaction_index is not None:
        cv = features[:, interaction_index]
        cd = display_features[:, interaction_index]
        clow = np.nanpercentile(features[:, interaction_index].astype(np.float), 5)
        chigh = np.nanpercentile(features[:, interaction_index].astype(np.float), 95)
        if type(cd[0]) == str:
            cname_map = {}
            for i in range(len(cv)):
                cname_map[cd[i]] = cv[i]
            cnames = list(cname_map.keys())
            categorical_interaction = True
        elif clow % 1 == 0 and chigh % 1 == 0 and len(set(features[:, interaction_index])) < 50:
            categorical_interaction = True

    # discritize colors for categorical features
    color_norm = None
    if categorical_interaction and clow != chigh:
        bounds = np.linspace(clow, chigh, chigh - clow + 2)
        color_norm = matplotlib.colors.BoundaryNorm(bounds, red_blue.N)

    # the actual scatter plot, TODO: adapt the dot_size to the number of data points?
    if interaction_index is not None:
        pl.scatter(xv, s, s=dot_size, linewidth=0, c=features[:, interaction_index], cmap=red_blue,
                   alpha=alpha, vmin=clow, vmax=chigh, norm=color_norm, rasterized=len(xv) > 500)
    else:
        pl.scatter(xv, s, s=dot_size, linewidth=0, color="#1E88E5",
                   alpha=alpha, rasterized=len(xv) > 500)

    if interaction_index != ind and interaction_index is not None:
        # draw the color bar
        if type(cd[0]) == str:
            tick_positions = [cname_map[n] for n in cnames]
            if len(tick_positions) == 2:
                tick_positions[0] -= 0.25
                tick_positions[1] += 0.25
            cb = pl.colorbar(ticks=tick_positions)
            cb.set_ticklabels(cnames)
        else:
            cb = pl.colorbar()

        cb.set_label(feature_names[interaction_index], size=13)
        cb.ax.tick_params(labelsize=11)
        if categorical_interaction:
            cb.ax.tick_params(length=0)
        cb.set_alpha(1)
        cb.outline.set_visible(False)
        bbox = cb.ax.get_window_extent().transformed(pl.gcf().dpi_scale_trans.inverted())
        cb.ax.set_aspect((bbox.height - 0.7) * 20)

    # make the plot more readable
    if interaction_index != ind:
        pl.gcf().set_size_inches(7.5, 5)
    else:
        pl.gcf().set_size_inches(6, 5)
    pl.xlabel(name, color=axis_color, fontsize=13)
    pl.ylabel(labels['VALUE_FOR'] % name, color=axis_color, fontsize=13)
    if title is not None:
        pl.title(title, color=axis_color, fontsize=13)
    pl.gca().xaxis.set_ticks_position('bottom')
    pl.gca().yaxis.set_ticks_position('left')
    pl.gca().spines['right'].set_visible(False)
    pl.gca().spines['top'].set_visible(False)
    pl.gca().tick_params(color=axis_color, labelcolor=axis_color, labelsize=11)
    for spine in pl.gca().spines.values():
        spine.set_edgecolor(axis_color)
    if type(xd[0]) == str:
        pl.xticks([name_map[n] for n in xnames], xnames, rotation='vertical', fontsize=11)
    # if show:
        # pl.show()
    return mpl_fig, interaction_index