Minor fix

utils/tal/anchor_generator.py

@@ -0,0 +1,38 @@
+import torch
+
+from utils.general import check_version
+
+TORCH_1_10 = check_version(torch.__version__, '1.10.0')
+
+
+def make_anchors(feats, strides, grid_cell_offset=0.5):
+    """Generate anchors from features."""
+    anchor_points, stride_tensor = [], []
+    assert feats is not None
+    dtype, device = feats[0].dtype, feats[0].device
+    for i, stride in enumerate(strides):
+        _, _, h, w = feats[i].shape
+        sx = torch.arange(end=w, device=device, dtype=dtype) + grid_cell_offset  # shift x
+        sy = torch.arange(end=h, device=device, dtype=dtype) + grid_cell_offset  # shift y
+        sy, sx = torch.meshgrid(sy, sx, indexing='ij') if TORCH_1_10 else torch.meshgrid(sy, sx)
+        anchor_points.append(torch.stack((sx, sy), -1).view(-1, 2))
+        stride_tensor.append(torch.full((h * w, 1), stride, dtype=dtype, device=device))
+    return torch.cat(anchor_points), torch.cat(stride_tensor)
+
+
+def dist2bbox(distance, anchor_points, xywh=True, dim=-1):
+    """Transform distance(ltrb) to box(xywh or xyxy)."""
+    lt, rb = torch.split(distance, 2, dim)
+    x1y1 = anchor_points - lt
+    x2y2 = anchor_points + rb
+    if xywh:
+        c_xy = (x1y1 + x2y2) / 2
+        wh = x2y2 - x1y1
+        return torch.cat((c_xy, wh), dim)  # xywh bbox
+    return torch.cat((x1y1, x2y2), dim)  # xyxy bbox
+
+
+def bbox2dist(anchor_points, bbox, reg_max):
+    """Transform bbox(xyxy) to dist(ltrb)."""
+    x1y1, x2y2 = torch.split(bbox, 2, -1)
+    return torch.cat((anchor_points - x1y1, x2y2 - anchor_points), -1).clamp(0, reg_max - 0.01)  # dist (lt, rb)