Revert FP16 `test.py` and `detect.py` inference to FP32 default (#3423)

detect.py

@@ -28,7 +28,7 @@ def detect(opt):
     # Initialize
     set_logging()
     device = select_device(opt.device)
-    half = device.type != 'cpu'  # half precision only supported on CUDA
+    half = opt.half and device.type != 'cpu'  # half precision only supported on CUDA
 
     # Load model
     model = attempt_load(weights, map_location=device)  # load FP32 model
@@ -172,6 +172,7 @@ if __name__ == '__main__':
     parser.add_argument('--line-thickness', default=3, type=int, help='bounding box thickness (pixels)')
     parser.add_argument('--hide-labels', default=False, action='store_true', help='hide labels')
     parser.add_argument('--hide-conf', default=False, action='store_true', help='hide confidences')
+    parser.add_argument('--half', type=bool, default=False, help='use FP16 half-precision inference')
     opt = parser.parse_args()
     print(opt)
     check_requirements(exclude=('tensorboard', 'pycocotools', 'thop'))

test.py

@@ -306,6 +306,7 @@ if __name__ == '__main__':
     parser.add_argument('--project', default='runs/test', help='save to project/name')
     parser.add_argument('--name', default='exp', help='save to project/name')
     parser.add_argument('--exist-ok', action='store_true', help='existing project/name ok, do not increment')
+    parser.add_argument('--half', type=bool, default=False, help='use FP16 half-precision inference')
     opt = parser.parse_args()
     opt.save_json |= opt.data.endswith('coco.yaml')
     opt.data = check_file(opt.data)  # check file
@@ -326,6 +327,7 @@ if __name__ == '__main__':
              save_txt=opt.save_txt | opt.save_hybrid,
              save_hybrid=opt.save_hybrid,
              save_conf=opt.save_conf,
+             half_precision=opt.half,
              opt=opt
              )