plot_ARD greatly improved, crossterm plotting enabled

GPy/kern/kern.py

@@ -66,12 +66,26 @@ class kern(Parameterized):
         Parameterized.setstate(self, state)
 
 
-    def plot_ARD(self, fignum=None, ax=None, title=None):
+    def plot_ARD(self, fignum=None, ax=None, title='', legend=False):
-        """If an ARD kernel is present, it bar-plots the ARD parameters"""
+        """If an ARD kernel is present, it bar-plots the ARD parameters,
+        :param fignum: figure number of the plot
+        :param ax: matplotlib axis to plot on
+        :param title: 
+            title of the plot, 
+            pass '' to not print a title
+            pass None for a generic title
+        """
         if ax is None:
             fig = pb.figure(fignum)
             ax = fig.add_subplot(111)
+        from GPy.util import Tango
+        from matplotlib.textpath import TextPath
+        Tango.reset()
+        xticklabels = []
+        bars = []
+        x0 = 0
         for p in self.parts:
+            c = Tango.nextMedium()
             if hasattr(p, 'ARD') and p.ARD:
                 if title is None:
                     ax.set_title('ARD parameters, %s kernel' % p.name)
@@ -82,10 +96,32 @@ class kern(Parameterized):
                 else:
                     ard_params = 1. / p.lengthscale
 
-                x = np.arange(len(ard_params))
+                x = np.arange(x0, x0 + len(ard_params))
-                ax.bar(x - 0.4, ard_params)
+                bars.append(ax.bar(x, ard_params, align='center', color=c, edgecolor='k', linewidth=1.2, label=p.name))
-                ax.set_xticks(x)
+                xticklabels.extend([r"$\mathrm{{{name}}}\ {x}$".format(name=p.name, x=i) for i in np.arange(len(ard_params))])
-                ax.set_xticklabels([r"${}$".format(i) for i in x])
+                x0 += len(ard_params)
+        x = np.arange(x0)
+        for bar in bars:
+            for patch, num in zip(bar.patches, np.arange(len(bar.patches))):
+                height = patch.get_height()
+                xi = patch.get_x() + patch.get_width() / 2.
+                va = 'top'
+                c = 'w'
+                t = TextPath((0, 0), "${xi}$".format(xi=xi), rotation=0, usetex=True, ha='center')
+                if patch.get_extents().height <= t.get_extents().height + 2:
+                    va = 'bottom'
+                    c = 'k'
+                ax.text(xi, height, "${xi}$".format(xi=int(num)), color=c, rotation=0, ha='center', va=va)
+        # for xi, t in zip(x, xticklabels):
+        #    ax.text(xi, maxi / 2, t, rotation=90, ha='center', va='center')
+        # ax.set_xticklabels(xticklabels, rotation=17)
+        ax.set_xticks([])
+        ax.set_xlim(-.5, x0 - .5)
+        if title is '':
+            ax.legend(bbox_to_anchor=(0., 1.02, 1., .102), loc=3,
+                      ncol=len(bars), mode="expand", borderaxespad=0.)
+        else:
+            ax.legend()
         return ax
 
     def _transform_gradients(self, g):