Corrected bug when pair bins contain only 1 value.

lib/scripts/generate_pairs.py

@@ -178,6 +178,7 @@ MESSAGE("Post-treatment of pair bins...")
 for i in range(nb_bins):
     pair_bins[i] = pair_bins[i].sort_values(by=["distance"])
     plot_bins = int(float(pair_bins[i]["distance"].max() - pair_bins[i]["distance"].min()) / 0.01)
+    plot_bins = max(1, plot_bins)
     pair_bins[i]["distance"].hist(bins = plot_bins)
 plt.title("Distributions of pair distance classes")
 if showplot: