Fix limit tests for plot (and warning in test)

1 files changed, 22 insertions, 10 deletions

diff --git a/src/python/gudhi/persistence_graphical_tools.py b/src/python/gudhi/persistence_graphical_tools.py
index 604018d1..930df825 100644
--- a/src/python/gudhi/persistence_graphical_tools.py
+++ b/src/python/gudhi/persistence_graphical_tools.py
@@ -190,12 +190,17 @@ def plot_persistence_barcode(
         if colormap == None:
             colormap = plt.cm.Set1.colors
 
-        x=[birth for (dim,(birth,death)) in persistence]
-        y=[(death - birth) if death != float("inf") else (infinity - birth) for (dim,(birth,death)) in persistence]
-        c=[colormap[dim] for (dim,(birth,death)) in persistence]
+        non_empty_diagram = len(persistence[0]) > 0
+        if non_empty_diagram:
+            x=[birth for (dim,(birth,death)) in persistence]
+            y=[(death - birth) if death != float("inf") else (infinity - birth) for (dim,(birth,death)) in persistence]
+            c=[colormap[dim] for (dim,(birth,death)) in persistence]
+        else:
+            x, y, c = [], [], []
+
         axes.barh(list(reversed(range(len(x)))), y, height=0.8, left=x, alpha=alpha, color=c, linewidth=0)
 
-        if legend:
+        if non_empty_diagram and legend:
             dimensions = list(set(item[0] for item in persistence))
             axes.legend(
                 handles=[mpatches.Patch(color=colormap[dim], label=str(dim)) for dim in dimensions], loc="lower right",
@@ -321,11 +326,16 @@ def plot_persistence_diagram(
         # line display of equation : birth = death
         axes.plot([axis_start, axis_end], [axis_start, axis_end], linewidth=1.0, color="k")
 
-        x=[birth for (dim,(birth,death)) in persistence]
-        y=[death if death != float("inf") else infinity for (dim,(birth,death)) in persistence]
-        c=[colormap[dim] for (dim,(birth,death)) in persistence]
+        non_empty_diagram = len(persistence[0]) > 0
+        if non_empty_diagram:
+            x=[birth for (dim,(birth,death)) in persistence]
+            y=[death if death != float("inf") else infinity for (dim,(birth,death)) in persistence]
+            c=[colormap[dim] for (dim,(birth,death)) in persistence]
+        else:
+            x, y, c = [], [], []
+
         axes.scatter(x,y,alpha=alpha,color=c)
-        if float("inf") in (death for (dim,(birth,death)) in persistence):
+        if non_empty_diagram and float("inf") in (death for (dim,(birth,death)) in persistence):
             # infinity line and text
             axes.plot([axis_start, axis_end], [infinity, infinity], linewidth=1.0, color="k", alpha=alpha)
             # Infinity label
@@ -337,7 +347,7 @@ def plot_persistence_diagram(
             axes.set_yticks(yt)
             axes.set_yticklabels(ytl)
 
-        if legend:
+        if non_empty_diagram and legend:
             dimensions = list(set(item[0] for item in persistence))
             axes.legend(handles=[mpatches.Patch(color=colormap[dim], label=str(dim)) for dim in dimensions])
 
@@ -482,6 +492,7 @@ def plot_persistence_density(
             zi = k(np.vstack([xi.flatten(), yi.flatten()]))
             # Make the plot
             img = axes.pcolormesh(xi, yi, zi.reshape(xi.shape), cmap=cmap, shading="auto")
+            non_empty_diagram = True
 
         # IndexError on empty diagrams, ValueError on only inf death values
         except (IndexError, ValueError):
@@ -489,6 +500,7 @@ def plot_persistence_density(
             birth_max = 1.0
             death_min = 0.0
             death_max = 1.0
+            non_empty_diagram = False
             pass
 
         # line display of equation : birth = death
@@ -504,7 +516,7 @@ def plot_persistence_density(
                 )
             )
 
-        if legend:
+        if non_empty_diagram and legend:
             plt.colorbar(img, ax=axes)
 
         axes.set_xlabel("Birth", fontsize=fontsize)