Fix val.py study plot (ultralytics#4831)

* Fix val.py study plot

* call plot_val_study

* Rename plot_study_txt to plot_val_study

utils/plots.py

@@ -247,15 +247,16 @@ def plot_targets_txt():  # from utils.plots import *; plot_targets_txt()
     plt.savefig('targets.jpg', dpi=200)
 
 
-def plot_study_txt(path='', x=None):  # from utils.plots import *; plot_study_txt()
-    # Plot study.txt generated by val.py
+def plot_val_study(file='', dir='', x=None):  # from utils.plots import *; plot_val_study()
+    # Plot file=study.txt generated by val.py (or plot all study*.txt in dir)
+    save_dir = Path(file).parent if file else Path(dir)
     plot2 = False  # plot additional results
     if plot2:
         ax = plt.subplots(2, 4, figsize=(10, 6), tight_layout=True)[1].ravel()
 
     fig2, ax2 = plt.subplots(1, 1, figsize=(8, 4), tight_layout=True)
     # for f in [Path(path) / f'study_coco_{x}.txt' for x in ['yolov5s6', 'yolov5m6', 'yolov5l6', 'yolov5x6']]:
-    for f in sorted(Path(path).glob('study*.txt')):
+    for f in sorted(save_dir.glob('study*.txt')):
         y = np.loadtxt(f, dtype=np.float32, usecols=[0, 1, 2, 3, 7, 8, 9], ndmin=2).T
         x = np.arange(y.shape[1]) if x is None else np.array(x)
         if plot2:
@@ -278,7 +279,9 @@ def plot_study_txt(path='', x=None):  # from utils.plots import *; plot_study_tx
     ax2.set_xlabel('GPU Speed (ms/img)')
     ax2.set_ylabel('COCO AP val')
     ax2.legend(loc='lower right')
-    plt.savefig(str(Path(path).name) + '.png', dpi=300)
+    f = save_dir / 'study.png'
+    print(f'Saving {f}...')
+    plt.savefig(f, dpi=300)
 
 
 def plot_labels(labels, names=(), save_dir=Path('')):

val.py

@@ -26,7 +26,7 @@
     check_suffix, check_yaml, box_iou, non_max_suppression, scale_coords, xyxy2xywh, xywh2xyxy, set_logging, \
     increment_path, colorstr
 from utils.metrics import ap_per_class, ConfusionMatrix
-from utils.plots import plot_images, output_to_target, plot_study_txt
+from utils.plots import output_to_target, plot_images, plot_val_study
 from utils.torch_utils import select_device, time_sync
 from utils.callbacks import Callbacks
 
@@ -348,7 +348,7 @@ def main(opt):
                 y.append(r + t)  # results and times
             np.savetxt(f, y, fmt='%10.4g')  # save
         os.system('zip -r study.zip study_*.txt')
-        plot_study_txt(x=x)  # plot
+        plot_val_study(x=x)  # plot
 
 
 if __name__ == "__main__":