Handle large padding

src/spandrel/__helpers/model_descriptor.py

@@ -101,7 +101,17 @@ def _pad(t: torch.Tensor, req: SizeRequirements):
     pad_w, pad_h = req.get_padding(w, h)
 
     if pad_w or pad_h:
-        return True, torch.nn.functional.pad(t, (0, pad_w, 0, pad_h), "reflect")
+        # reflect padding only allows a maximum padding of size - 1
+        reflect_pad_w = min(pad_w, w - 1)
+        reflect_pad_h = min(pad_h, h - 1)
+        t = torch.nn.functional.pad(t, (0, reflect_pad_w, 0, reflect_pad_h), "reflect")
+
+        # do the rest of the padding (if any) with replicate, which has no such restrictions
+        pad_w -= reflect_pad_w
+        pad_h -= reflect_pad_h
+        t = torch.nn.functional.pad(t, (0, pad_w, 0, pad_h), "replicate")
+
+        return True, t
     else:
         return False, t