Workaround when torch.hypot is not available

roma/euler.py

@@ -159,7 +159,7 @@ def unitquat_to_euler(convention : str, quat, degrees=False, epsilon=1e-7):
     # Compute second angle...
     angles = [torch.empty(N, device=quat.device, dtype=quat.dtype) for _ in range(3)]
 
-    angles[1] = 2 * torch.atan2(torch.hypot(c, d), torch.hypot(a, b))
+    angles[1] = 2 * torch.atan2(roma.internal.hypot(c, d), roma.internal.hypot(a, b))
 
     # ... and check if equal to is 0 or pi, causing a singularity
     case1 = torch.abs(angles[1]) <= epsilon

roma/internal.py

@@ -104,4 +104,12 @@ def norm(x, dim=None, keepdim=False):
 except AttributeError:
     # torch.linalg.norm was introduced in PyTorch 1.7, and torch.norm is deprecated.
     def norm(x, dim=None, keepdim=False):
-        return torch.norm(x, dim=dim, keepdim=keepdim)
+        return torch.norm(x, dim=dim, keepdim=keepdim)
+
+try:
+    torch.hypot
+    hypot = torch.hypot
+except AttributeError:
+    # torch.hypot is not available in PyTorch 1.6.
+    def hypot(x, y):
+        return torch.sqrt(torch.square(x) + torch.square(y))