feat: Change precision-recall plots to work with any number of classes

The plprecision-recall plots now look as they should with any number of classes.

Author: pierluigiferrari

ssd300_evaluation.ipynb

@@ -401,12 +401,13 @@
     }
    ],
    "source": [
-    "m = 10\n",
+    "m = (n_classes + 1) // 2\n",
     "n = 2\n",
     "\n",
-    "fig, cells = plt.subplots(m, n, figsize=(16,80))\n",
+    "fig, cells = plt.subplots(m, n, figsize=(n*8,m*8))\n",
     "for i in range(m):\n",
     "    for j in range(n):\n",
+    "        if n*i+j+1 > n_classes: break\n",
     "        cells[i, j].plot(recalls[n*i+j+1], precisions[n*i+j+1], color='blue', linewidth=1.0)\n",
     "        cells[i, j].set_xlabel('recall', fontsize=14)\n",
     "        cells[i, j].set_ylabel('precision', fontsize=14)\n",