Weighted Umeyama.

Summary:
1. Introduced weights to Umeyama implementation. This will be needed for weighted ePnP but is useful on its own.
2. Refactored to use the same code for the Pointclouds mask and passed weights.
3. Added test cases with random weights.
4. Fixed a bug in tests that calls the function with 0 points (fails randomly in Pytorch 1.3, will be fixed in the next release: https://github.com/pytorch/pytorch/issues/31421 ).

Reviewed By: gkioxari

Differential Revision: D20070293

fbshipit-source-id: e9f549507ef6dcaa0688a0f17342e6d7a9a4336c

tests/common_testing.py

@@ -1,5 +1,6 @@
 # Copyright (c) Facebook, Inc. and its affiliates. All rights reserved.
 
+from typing import Optional
 
 import unittest
 
@@ -35,13 +36,15 @@ class TestCaseMixin(unittest.TestCase):
         *,
         rtol: float = 1e-05,
         atol: float = 1e-08,
-        equal_nan: bool = False
+        equal_nan: bool = False,
+        msg: Optional[str] = None,
     ) -> None:
         """
         Verify that two tensors or arrays are the same shape and close.
         Args:
             input, other: two tensors or two arrays.
             rtol, atol, equal_nan: as for torch.allclose.
+            msg: message in case the assertion is violated.
         Note:
             Optional arguments here are all keyword-only, to avoid confusion
             with msg arguments on other assert functions.
@@ -54,5 +57,7 @@ class TestCaseMixin(unittest.TestCase):
                 input, other, rtol=rtol, atol=atol, equal_nan=equal_nan
             )
         else:
-            close = np.allclose(input, other, rtol=rtol, atol=atol, equal_nan=equal_nan)
-        self.assertTrue(close)
+            close = np.allclose(
+                input, other, rtol=rtol, atol=atol, equal_nan=equal_nan
+            )
+        self.assertTrue(close, msg)