Grid indices overflow bug fix (#1313)

utils/general.py

@@ -1,5 +1,6 @@
 import glob
 import logging
+import math
 import os
 import platform
 import random
@@ -12,7 +13,6 @@ from copy import copy
 from pathlib import Path
 
 import cv2
-import math
 import matplotlib
 import matplotlib.pyplot as plt
 import numpy as np
@@ -589,7 +589,7 @@ def build_targets(p, targets, model):
 
         # Append
         a = t[:, 6].long()  # anchor indices
-        indices.append((b, a, gj, gi))  # image, anchor, grid indices
+        indices.append((b, a, gj.clamp_(0, gain[3]), gi.clamp_(0, gain[2])))  # image, anchor, grid indices
         tbox.append(torch.cat((gxy - gij, gwh), 1))  # box
         anch.append(anchors[a])  # anchors
         tcls.append(c)  # class
@@ -1096,7 +1096,8 @@ def plot_images(images, targets, paths=None, fname='images.jpg', names=None, max
         cv2.rectangle(mosaic, (block_x, block_y), (block_x + w, block_y + h), (255, 255, 255), thickness=3)
 
     if fname is not None:
-        mosaic = cv2.resize(mosaic, (int(ns * w * 0.5), int(ns * h * 0.5)), interpolation=cv2.INTER_AREA)
+        r = min(1280. / max(h, w) / ns, 1.0)  # ratio to limit image size
+        mosaic = cv2.resize(mosaic, (int(ns * w * r), int(ns * h * r)), interpolation=cv2.INTER_AREA)
         # cv2.imwrite(fname, cv2.cvtColor(mosaic, cv2.COLOR_BGR2RGB))  # cv2 save
         Image.fromarray(mosaic).save(fname)  # PIL save
     return mosaic