File size: 43,178 Bytes
7088d16
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
# Copyright (c) Meta Platforms, Inc. and affiliates.
# All rights reserved.
#
# This source code is licensed under the BSD-style license found in the
# LICENSE file in the root directory of this source tree.

import unittest
from collections import namedtuple

import numpy as np
import torch
import torch.nn.functional as F
from pytorch3d.loss import chamfer_distance
from pytorch3d.structures.pointclouds import Pointclouds

from .common_testing import get_random_cuda_device, TestCaseMixin


# Output of init_pointclouds
points_normals = namedtuple(
    "points_normals", "p1_lengths p2_lengths cloud1 cloud2 p1 p2 n1 n2 weights"
)


class TestChamfer(TestCaseMixin, unittest.TestCase):
    def setUp(self) -> None:
        super().setUp()
        torch.manual_seed(1)

    @staticmethod
    def init_pointclouds(
        N, P1, P2, device, requires_grad: bool = True, allow_empty: bool = True
    ):
        """
        Create 2 pointclouds object and associated padded points/normals tensors by
        starting from lists. The clouds and tensors have the same data. The
        leaf nodes for the clouds are a list of tensors. The padded tensor can be
        used directly as a leaf node.
        """
        low = 0 if allow_empty else 1
        p1_lengths = torch.randint(low, P1, size=(N,), dtype=torch.int64, device=device)
        p2_lengths = torch.randint(low, P2, size=(N,), dtype=torch.int64, device=device)
        P1 = p1_lengths.max().item()
        P2 = p2_lengths.max().item()
        weights = torch.rand((N,), dtype=torch.float32, device=device)

        # list of points and normals tensors
        p1 = torch.rand((N, P1, 3), dtype=torch.float32, device=device)
        p2 = torch.rand((N, P2, 3), dtype=torch.float32, device=device)
        n1 = torch.rand((N, P1, 3), dtype=torch.float32, device=device)
        n2 = torch.rand((N, P2, 3), dtype=torch.float32, device=device)
        n1 /= n1.norm(dim=-1, p=2, keepdim=True)
        n2 /= n2.norm(dim=-1, p=2, keepdim=True)

        p1_list = []
        p2_list = []
        n1_list = []
        n2_list = []
        for i in range(N):
            l1 = p1_lengths[i]
            l2 = p2_lengths[i]
            p1_list.append(p1[i, :l1].clone())
            p2_list.append(p2[i, :l2].clone())
            n1_list.append(n1[i, :l1].clone())
            n2_list.append(n2[i, :l2].clone())

        # Set requires_grad for all tensors in the lists and
        # padded tensors.
        if requires_grad:
            for p in p2_list + p1_list + n1_list + n2_list + [p1, p2, n1, n2]:
                p.requires_grad = True

        # Create pointclouds objects
        cloud1 = Pointclouds(points=p1_list, normals=n1_list)
        cloud2 = Pointclouds(points=p2_list, normals=n2_list)

        # Return pointclouds objects and padded tensors
        return points_normals(
            p1_lengths=p1_lengths,
            p2_lengths=p2_lengths,
            cloud1=cloud1,
            cloud2=cloud2,
            p1=p1,
            p2=p2,
            n1=n1,
            n2=n2,
            weights=weights,
        )

    @staticmethod
    def chamfer_distance_naive_pointclouds(
        p1, p2, norm: int = 2, device="cpu", abs_cosine=True
    ):
        """
        Naive iterative implementation of nearest neighbor and chamfer distance.
        x and y are assumed to be pointclouds objects with points and optionally normals.
        This functions supports heterogeneous pointclouds in a batch.
        Returns lists of the unreduced loss and loss_normals.
        """
        x = p1.points_padded()
        y = p2.points_padded()
        N, P1, D = x.shape
        P2 = y.size(1)
        x_lengths = p1.num_points_per_cloud()
        y_lengths = p2.num_points_per_cloud()
        x_normals = p1.normals_padded()
        y_normals = p2.normals_padded()

        return_normals = x_normals is not None and y_normals is not None

        # Initialize all distances to + inf
        dist = torch.ones((N, P1, P2), dtype=torch.float32, device=device) * np.inf

        x_mask = (
            torch.arange(P1, device=x.device)[None] >= x_lengths[:, None]
        )  # shape [N, P1]
        y_mask = (
            torch.arange(P2, device=y.device)[None] >= y_lengths[:, None]
        )  # shape [N, P2]

        is_x_heterogeneous = (x_lengths != P1).any()
        is_y_heterogeneous = (y_lengths != P2).any()
        # Only calculate the distances for the points which are not masked
        for n in range(N):
            for i1 in range(x_lengths[n]):
                for i2 in range(y_lengths[n]):
                    if norm == 2:
                        dist[n, i1, i2] = torch.sum((x[n, i1, :] - y[n, i2, :]) ** 2)
                    elif norm == 1:
                        dist[n, i1, i2] = torch.sum(
                            torch.abs(x[n, i1, :] - y[n, i2, :])
                        )
                    else:
                        raise ValueError("No support for norm %d" % (norm))

        x_dist = torch.min(dist, dim=2)[0]  # (N, P1)
        y_dist = torch.min(dist, dim=1)[0]  # (N, P2)

        if is_x_heterogeneous:
            x_dist[x_mask] = 0.0
        if is_y_heterogeneous:
            y_dist[y_mask] = 0.0

        loss = [x_dist, y_dist]

        lnorm = [x.new_zeros(()), x.new_zeros(())]

        if return_normals:
            x_index = dist.argmin(2).view(N, P1, 1).expand(N, P1, 3)
            y_index = dist.argmin(1).view(N, P2, 1).expand(N, P2, 3)
            cosine_sim1 = F.cosine_similarity(
                x_normals, y_normals.gather(1, x_index), dim=2, eps=1e-6
            )
            cosine_sim2 = F.cosine_similarity(
                y_normals, x_normals.gather(1, y_index), dim=2, eps=1e-6
            )

            if abs_cosine:
                lnorm1 = 1 - torch.abs(cosine_sim1)
                lnorm2 = 1 - torch.abs(cosine_sim2)
            else:
                lnorm1 = 1 - cosine_sim1
                lnorm2 = 1 - cosine_sim2

            if is_x_heterogeneous:
                lnorm1[x_mask] = 0.0
            if is_y_heterogeneous:
                lnorm2[y_mask] = 0.0

            lnorm = [lnorm1, lnorm2]  # [(N, P1), (N, P2)]

        return loss, lnorm

    @staticmethod
    def chamfer_distance_naive(
        x, y, x_normals=None, y_normals=None, norm: int = 2, abs_cosine=True
    ):
        """
        Naive iterative implementation of nearest neighbor and chamfer distance.
        Returns lists of the unreduced loss and loss_normals. This naive
        version only supports homogeneous pointcouds in a batch.
        """
        N, P1, D = x.shape
        P2 = y.size(1)
        device = x.device
        return_normals = x_normals is not None and y_normals is not None
        dist = torch.zeros((N, P1, P2), dtype=torch.float32, device=device)

        for n in range(N):
            for i1 in range(P1):
                for i2 in range(P2):
                    if norm == 2:
                        dist[n, i1, i2] = torch.sum((x[n, i1, :] - y[n, i2, :]) ** 2)
                    elif norm == 1:
                        dist[n, i1, i2] = torch.sum(
                            torch.abs(x[n, i1, :] - y[n, i2, :])
                        )
                    else:
                        raise ValueError("No support for norm %d" % (norm))

        loss = [
            torch.min(dist, dim=2)[0],  # (N, P1)
            torch.min(dist, dim=1)[0],  # (N, P2)
        ]
        lnorm = [x.new_zeros(()), x.new_zeros(())]

        if return_normals:
            x_index = dist.argmin(2).view(N, P1, 1).expand(N, P1, 3)
            y_index = dist.argmin(1).view(N, P2, 1).expand(N, P2, 3)

            cosine_sim1 = F.cosine_similarity(
                x_normals, y_normals.gather(1, x_index), dim=2, eps=1e-6
            )
            cosine_sim2 = F.cosine_similarity(
                y_normals, x_normals.gather(1, y_index), dim=2, eps=1e-6
            )

            if abs_cosine:
                lnorm1 = 1 - torch.abs(cosine_sim1)
                lnorm2 = 1 - torch.abs(cosine_sim2)
            else:
                lnorm1 = 1 - cosine_sim1
                lnorm2 = 1 - cosine_sim2

            lnorm = [lnorm1, lnorm2]  # [(N, P1), (N, P2)]

        return loss, lnorm

    def test_chamfer_point_batch_reduction_mean(self):
        """
        Compare output of vectorized chamfer loss with naive implementation
        for the default settings (point_reduction = "mean" and batch_reduction = "mean")
        and no normals.
        This tests only uses homogeneous pointclouds.
        """
        N, max_P1, max_P2 = 7, 10, 18
        device = get_random_cuda_device()

        for norm in [1, 2]:
            points_normals = TestChamfer.init_pointclouds(N, max_P1, max_P2, device)
            p1 = points_normals.p1
            p2 = points_normals.p2
            weights = points_normals.weights
            p11 = p1.detach().clone()
            p22 = p2.detach().clone()
            p11.requires_grad = True
            p22.requires_grad = True
            P1 = p1.shape[1]
            P2 = p2.shape[1]

            pred_loss, pred_loss_norm = TestChamfer.chamfer_distance_naive(
                p1, p2, norm=norm
            )

            # point_reduction = "mean".
            loss, loss_norm = chamfer_distance(p11, p22, weights=weights, norm=norm)
            pred_loss = pred_loss[0].sum(1) / P1 + pred_loss[1].sum(1) / P2
            pred_loss *= weights
            pred_loss = pred_loss.sum() / weights.sum()

            self.assertClose(loss, pred_loss)
            self.assertTrue(loss_norm is None)

            # Check gradients
            self._check_gradients(loss, None, pred_loss, None, p1, p11, p2, p22)

    def test_chamfer_vs_naive_pointcloud(self):
        """
        Test the default settings for chamfer_distance
        (point reduction = "mean" and batch_reduction="mean") but with heterogeneous
        pointclouds as input. Compare with the naive implementation of chamfer
        which supports heterogeneous pointcloud objects.
        """
        N, max_P1, max_P2 = 3, 70, 70
        device = get_random_cuda_device()

        for norm in [1, 2]:
            points_normals = TestChamfer.init_pointclouds(N, max_P1, max_P2, device)
            weights = points_normals.weights
            x_lengths = points_normals.p1_lengths
            y_lengths = points_normals.p2_lengths

            # Chamfer with tensors as input for heterogeneous pointclouds.
            cham_tensor, norm_tensor = chamfer_distance(
                points_normals.p1,
                points_normals.p2,
                x_normals=points_normals.n1,
                y_normals=points_normals.n2,
                x_lengths=points_normals.p1_lengths,
                y_lengths=points_normals.p2_lengths,
                weights=weights,
                norm=norm,
            )

            # Chamfer with pointclouds as input.
            pred_loss, pred_norm_loss = TestChamfer.chamfer_distance_naive_pointclouds(
                points_normals.cloud1, points_normals.cloud2, norm=norm, device=device
            )

            # Mean reduction point loss.
            pred_loss[0] *= weights.view(N, 1)
            pred_loss[1] *= weights.view(N, 1)
            pred_loss_mean = (
                pred_loss[0].sum(1) / x_lengths + pred_loss[1].sum(1) / y_lengths
            )
            pred_loss_mean = pred_loss_mean.sum()
            pred_loss_mean /= weights.sum()

            # Mean reduction norm loss.
            pred_norm_loss[0] *= weights.view(N, 1)
            pred_norm_loss[1] *= weights.view(N, 1)
            pred_norm_loss_mean = (
                pred_norm_loss[0].sum(1) / x_lengths
                + pred_norm_loss[1].sum(1) / y_lengths
            )
            pred_norm_loss_mean = pred_norm_loss_mean.sum() / weights.sum()

            self.assertClose(pred_loss_mean, cham_tensor)
            self.assertClose(pred_norm_loss_mean, norm_tensor)

            self._check_gradients(
                cham_tensor,
                norm_tensor,
                pred_loss_mean,
                pred_norm_loss_mean,
                points_normals.cloud1.points_list(),
                points_normals.p1,
                points_normals.cloud2.points_list(),
                points_normals.p2,
                points_normals.cloud1.normals_list(),
                points_normals.n1,
                points_normals.cloud2.normals_list(),
                points_normals.n2,
                x_lengths,
                y_lengths,
            )

    def test_single_directional_chamfer_vs_naive_pointcloud(self):
        """
        Test the single directional settings for chamfer_distance
        (point reduction = "mean" and batch_reduction="mean") but with heterogeneous
        pointclouds as input. Compare with the naive implementation of chamfer
        which supports heterogeneous pointcloud objects.
        """
        N, max_P1, max_P2 = 3, 70, 70
        device = get_random_cuda_device()

        for norm in [1, 2]:
            for abs_cosine in [True, False]:
                points_normals = TestChamfer.init_pointclouds(N, max_P1, max_P2, device)
                weights = points_normals.weights
                x_lengths = points_normals.p1_lengths
                y_lengths = points_normals.p2_lengths

                # Chamfer with tensors as input for heterogeneous pointclouds.
                cham_tensor, norm_tensor = chamfer_distance(
                    points_normals.p1,
                    points_normals.p2,
                    x_normals=points_normals.n1,
                    y_normals=points_normals.n2,
                    x_lengths=points_normals.p1_lengths,
                    y_lengths=points_normals.p2_lengths,
                    weights=weights,
                    norm=norm,
                    single_directional=True,
                    abs_cosine=abs_cosine,
                )

                # Chamfer with pointclouds as input.
                (
                    pred_loss,
                    pred_norm_loss,
                ) = TestChamfer.chamfer_distance_naive_pointclouds(
                    points_normals.cloud1,
                    points_normals.cloud2,
                    norm=norm,
                    device=device,
                    abs_cosine=abs_cosine,
                )

                # Mean reduction point loss.
                pred_loss[0] *= weights.view(N, 1)
                pred_loss_mean = pred_loss[0].sum(1) / x_lengths
                pred_loss_mean = pred_loss_mean.sum()
                pred_loss_mean /= weights.sum()

                # Mean reduction norm loss.
                pred_norm_loss[0] *= weights.view(N, 1)
                pred_norm_loss_mean = pred_norm_loss[0].sum(1) / x_lengths
                pred_norm_loss_mean = pred_norm_loss_mean.sum() / weights.sum()

                self.assertClose(pred_loss_mean, cham_tensor)
                self.assertClose(pred_norm_loss_mean, norm_tensor)

                self._check_gradients(
                    cham_tensor,
                    norm_tensor,
                    pred_loss_mean,
                    pred_norm_loss_mean,
                    points_normals.cloud1.points_list(),
                    points_normals.p1,
                    points_normals.cloud2.points_list(),
                    points_normals.p2,
                    points_normals.cloud1.normals_list(),
                    points_normals.n1,
                    points_normals.cloud2.normals_list(),
                    points_normals.n2,
                    x_lengths,
                    y_lengths,
                )

    def test_chamfer_pointcloud_object_withnormals(self):
        N = 5
        P1, P2 = 100, 100
        device = get_random_cuda_device()

        reductions = [
            ("sum", "sum"),
            ("mean", "sum"),
            ("sum", "mean"),
            ("mean", "mean"),
            ("sum", None),
            ("mean", None),
            (None, None),
        ]
        for point_reduction, batch_reduction in reductions:
            # Reinitialize all the tensors so that the
            # backward pass can be computed.
            points_normals = TestChamfer.init_pointclouds(
                N, P1, P2, device, allow_empty=False
            )

            # Chamfer with pointclouds as input.
            cham_cloud, norm_cloud = chamfer_distance(
                points_normals.cloud1,
                points_normals.cloud2,
                point_reduction=point_reduction,
                batch_reduction=batch_reduction,
            )

            # Chamfer with tensors as input.
            cham_tensor, norm_tensor = chamfer_distance(
                points_normals.p1,
                points_normals.p2,
                x_lengths=points_normals.p1_lengths,
                y_lengths=points_normals.p2_lengths,
                x_normals=points_normals.n1,
                y_normals=points_normals.n2,
                point_reduction=point_reduction,
                batch_reduction=batch_reduction,
            )

            if point_reduction is None:
                cham_tensor_bidirectional = torch.hstack(
                    [cham_tensor[0], cham_tensor[1]]
                )
                norm_tensor_bidirectional = torch.hstack(
                    [norm_tensor[0], norm_tensor[1]]
                )
                cham_cloud_bidirectional = torch.hstack([cham_cloud[0], cham_cloud[1]])
                norm_cloud_bidirectional = torch.hstack([norm_cloud[0], norm_cloud[1]])
                self.assertClose(cham_cloud_bidirectional, cham_tensor_bidirectional)
                self.assertClose(norm_cloud_bidirectional, norm_tensor_bidirectional)
                self._check_gradients(
                    cham_tensor_bidirectional,
                    norm_tensor_bidirectional,
                    cham_cloud_bidirectional,
                    norm_cloud_bidirectional,
                    points_normals.cloud1.points_list(),
                    points_normals.p1,
                    points_normals.cloud2.points_list(),
                    points_normals.p2,
                    points_normals.cloud1.normals_list(),
                    points_normals.n1,
                    points_normals.cloud2.normals_list(),
                    points_normals.n2,
                    points_normals.p1_lengths,
                    points_normals.p2_lengths,
                )
            else:
                self.assertClose(cham_cloud, cham_tensor)
                self.assertClose(norm_cloud, norm_tensor)
                self._check_gradients(
                    cham_tensor,
                    norm_tensor,
                    cham_cloud,
                    norm_cloud,
                    points_normals.cloud1.points_list(),
                    points_normals.p1,
                    points_normals.cloud2.points_list(),
                    points_normals.p2,
                    points_normals.cloud1.normals_list(),
                    points_normals.n1,
                    points_normals.cloud2.normals_list(),
                    points_normals.n2,
                    points_normals.p1_lengths,
                    points_normals.p2_lengths,
                )

    def test_chamfer_pointcloud_object_nonormals(self):
        N = 5
        P1, P2 = 100, 100
        device = get_random_cuda_device()

        reductions = [
            ("sum", "sum"),
            ("mean", "sum"),
            ("sum", "mean"),
            ("mean", "mean"),
            ("sum", None),
            ("mean", None),
            (None, None),
        ]
        for point_reduction, batch_reduction in reductions:
            # Reinitialize all the tensors so that the
            # backward pass can be computed.
            points_normals = TestChamfer.init_pointclouds(
                N, P1, P2, device, allow_empty=False
            )

            # Chamfer with pointclouds as input.
            cham_cloud, _ = chamfer_distance(
                points_normals.cloud1,
                points_normals.cloud2,
                point_reduction=point_reduction,
                batch_reduction=batch_reduction,
            )

            # Chamfer with tensors as input.
            cham_tensor, _ = chamfer_distance(
                points_normals.p1,
                points_normals.p2,
                x_lengths=points_normals.p1_lengths,
                y_lengths=points_normals.p2_lengths,
                point_reduction=point_reduction,
                batch_reduction=batch_reduction,
            )

            if point_reduction is None:
                cham_tensor_bidirectional = torch.hstack(
                    [cham_tensor[0], cham_tensor[1]]
                )
                cham_cloud_bidirectional = torch.hstack([cham_cloud[0], cham_cloud[1]])
                self.assertClose(cham_cloud_bidirectional, cham_tensor_bidirectional)
                self._check_gradients(
                    cham_tensor_bidirectional,
                    None,
                    cham_cloud_bidirectional,
                    None,
                    points_normals.cloud1.points_list(),
                    points_normals.p1,
                    points_normals.cloud2.points_list(),
                    points_normals.p2,
                    lengths1=points_normals.p1_lengths,
                    lengths2=points_normals.p2_lengths,
                )
            else:
                self.assertClose(cham_cloud, cham_tensor)
                self._check_gradients(
                    cham_tensor,
                    None,
                    cham_cloud,
                    None,
                    points_normals.cloud1.points_list(),
                    points_normals.p1,
                    points_normals.cloud2.points_list(),
                    points_normals.p2,
                    lengths1=points_normals.p1_lengths,
                    lengths2=points_normals.p2_lengths,
                )

    def test_chamfer_point_reduction_mean(self):
        """
        Compare output of vectorized chamfer loss with naive implementation
        for point_reduction = "mean" and batch_reduction = None.
        """
        N, max_P1, max_P2 = 7, 10, 18
        device = get_random_cuda_device()
        points_normals = TestChamfer.init_pointclouds(N, max_P1, max_P2, device)
        p1 = points_normals.p1
        p2 = points_normals.p2
        p1_normals = points_normals.n1
        p2_normals = points_normals.n2
        weights = points_normals.weights
        p11 = p1.detach().clone()
        p22 = p2.detach().clone()
        p11.requires_grad = True
        p22.requires_grad = True
        P1 = p1.shape[1]
        P2 = p2.shape[1]

        pred_loss, pred_loss_norm = TestChamfer.chamfer_distance_naive(
            p1, p2, x_normals=p1_normals, y_normals=p2_normals
        )

        # point_reduction = "mean".
        loss, loss_norm = chamfer_distance(
            p11,
            p22,
            x_normals=p1_normals,
            y_normals=p2_normals,
            weights=weights,
            batch_reduction=None,
            point_reduction="mean",
        )
        pred_loss_mean = pred_loss[0].sum(1) / P1 + pred_loss[1].sum(1) / P2
        pred_loss_mean *= weights
        self.assertClose(loss, pred_loss_mean)

        pred_loss_norm_mean = (
            pred_loss_norm[0].sum(1) / P1 + pred_loss_norm[1].sum(1) / P2
        )
        pred_loss_norm_mean *= weights
        self.assertClose(loss_norm, pred_loss_norm_mean)

        # Check gradients
        self._check_gradients(
            loss, loss_norm, pred_loss_mean, pred_loss_norm_mean, p1, p11, p2, p22
        )

    def test_single_direction_chamfer_point_reduction_mean(self):
        """
        Compare output of vectorized chamfer loss with naive implementation
        for point_reduction = "mean" and batch_reduction = None.
        """
        N, max_P1, max_P2 = 7, 10, 18
        device = get_random_cuda_device()
        points_normals = TestChamfer.init_pointclouds(N, max_P1, max_P2, device)
        p1 = points_normals.p1
        p2 = points_normals.p2
        p1_normals = points_normals.n1
        p2_normals = points_normals.n2
        weights = points_normals.weights
        p11 = p1.detach().clone()
        p22 = p2.detach().clone()
        p11.requires_grad = True
        p22.requires_grad = True
        P1 = p1.shape[1]

        pred_loss, pred_loss_norm = TestChamfer.chamfer_distance_naive(
            p1, p2, x_normals=p1_normals, y_normals=p2_normals
        )

        # point_reduction = "mean".
        loss, loss_norm = chamfer_distance(
            p11,
            p22,
            x_normals=p1_normals,
            y_normals=p2_normals,
            weights=weights,
            batch_reduction=None,
            point_reduction="mean",
            single_directional=True,
        )
        pred_loss_mean = pred_loss[0].sum(1) / P1
        pred_loss_mean *= weights
        self.assertClose(loss, pred_loss_mean)

        pred_loss_norm_mean = pred_loss_norm[0].sum(1) / P1
        pred_loss_norm_mean *= weights
        self.assertClose(loss_norm, pred_loss_norm_mean)

        # Check gradients
        self._check_gradients(
            loss, loss_norm, pred_loss_mean, pred_loss_norm_mean, p1, p11, p2, p22
        )

    def test_chamfer_point_reduction_sum(self):
        """
        Compare output of vectorized chamfer loss with naive implementation
        for point_reduction = "sum" and batch_reduction = None.
        """
        N, P1, P2 = 7, 10, 18
        device = get_random_cuda_device()
        points_normals = TestChamfer.init_pointclouds(N, P1, P2, device)
        p1 = points_normals.p1
        p2 = points_normals.p2
        p1_normals = points_normals.n1
        p2_normals = points_normals.n2
        weights = points_normals.weights
        p11 = p1.detach().clone()
        p22 = p2.detach().clone()
        p11.requires_grad = True
        p22.requires_grad = True

        pred_loss, pred_loss_norm = TestChamfer.chamfer_distance_naive(
            p1, p2, x_normals=p1_normals, y_normals=p2_normals
        )

        loss, loss_norm = chamfer_distance(
            p11,
            p22,
            x_normals=p1_normals,
            y_normals=p2_normals,
            weights=weights,
            batch_reduction=None,
            point_reduction="sum",
        )
        pred_loss_sum = pred_loss[0].sum(1) + pred_loss[1].sum(1)
        pred_loss_sum *= weights
        self.assertClose(loss, pred_loss_sum)

        pred_loss_norm_sum = pred_loss_norm[0].sum(1) + pred_loss_norm[1].sum(1)
        pred_loss_norm_sum *= weights
        self.assertClose(loss_norm, pred_loss_norm_sum)

        # Check gradients
        self._check_gradients(
            loss, loss_norm, pred_loss_sum, pred_loss_norm_sum, p1, p11, p2, p22
        )

    def test_single_directional_chamfer_point_reduction_sum(self):
        """
        Compare output of vectorized single directional chamfer loss with naive implementation
        for point_reduction = "sum" and batch_reduction = None.
        """
        N, P1, P2 = 7, 10, 18
        device = get_random_cuda_device()
        points_normals = TestChamfer.init_pointclouds(N, P1, P2, device)
        p1 = points_normals.p1
        p2 = points_normals.p2
        p1_normals = points_normals.n1
        p2_normals = points_normals.n2
        weights = points_normals.weights
        p11 = p1.detach().clone()
        p22 = p2.detach().clone()
        p11.requires_grad = True
        p22.requires_grad = True

        pred_loss, pred_loss_norm = TestChamfer.chamfer_distance_naive(
            p1, p2, x_normals=p1_normals, y_normals=p2_normals
        )

        loss, loss_norm = chamfer_distance(
            p11,
            p22,
            x_normals=p1_normals,
            y_normals=p2_normals,
            weights=weights,
            batch_reduction=None,
            point_reduction="sum",
            single_directional=True,
        )
        pred_loss_sum = pred_loss[0].sum(1)
        pred_loss_sum *= weights
        self.assertClose(loss, pred_loss_sum)

        pred_loss_norm_sum = pred_loss_norm[0].sum(1)
        pred_loss_norm_sum *= weights
        self.assertClose(loss_norm, pred_loss_norm_sum)

        # Check gradients
        self._check_gradients(
            loss, loss_norm, pred_loss_sum, pred_loss_norm_sum, p1, p11, p2, p22
        )

    def test_chamfer_point_reduction_none(self):
        """
        Compare output of vectorized chamfer loss with naive implementation
        for point_reduction = None and batch_reduction = None.
        """
        N, max_P1, max_P2 = 7, 10, 18
        device = get_random_cuda_device()
        points_normals = TestChamfer.init_pointclouds(N, max_P1, max_P2, device)
        p1 = points_normals.p1
        p2 = points_normals.p2
        p1_normals = points_normals.n1
        p2_normals = points_normals.n2
        p11 = p1.detach().clone()
        p22 = p2.detach().clone()
        p11.requires_grad = True
        p22.requires_grad = True

        pred_loss, pred_loss_norm = TestChamfer.chamfer_distance_naive(
            p1, p2, x_normals=p1_normals, y_normals=p2_normals
        )

        # point_reduction = None
        loss, loss_norm = chamfer_distance(
            p11,
            p22,
            x_normals=p1_normals,
            y_normals=p2_normals,
            batch_reduction=None,
            point_reduction=None,
        )

        loss_bidirectional = torch.hstack([loss[0], loss[1]])
        pred_loss_bidirectional = torch.hstack([pred_loss[0], pred_loss[1]])
        loss_norm_bidirectional = torch.hstack([loss_norm[0], loss_norm[1]])
        pred_loss_norm_bidirectional = torch.hstack(
            [pred_loss_norm[0], pred_loss_norm[1]]
        )

        self.assertClose(loss_bidirectional, pred_loss_bidirectional)
        self.assertClose(loss_norm_bidirectional, pred_loss_norm_bidirectional)

        # Check gradients
        self._check_gradients(
            loss_bidirectional,
            loss_norm_bidirectional,
            pred_loss_bidirectional,
            pred_loss_norm_bidirectional,
            p1,
            p11,
            p2,
            p22,
        )

    def test_single_direction_chamfer_point_reduction_none(self):
        """
        Compare output of vectorized chamfer loss with naive implementation
        for point_reduction = None and batch_reduction = None.
        """
        N, max_P1, max_P2 = 7, 10, 18
        device = get_random_cuda_device()
        points_normals = TestChamfer.init_pointclouds(N, max_P1, max_P2, device)
        p1 = points_normals.p1
        p2 = points_normals.p2
        p1_normals = points_normals.n1
        p2_normals = points_normals.n2
        p11 = p1.detach().clone()
        p22 = p2.detach().clone()
        p11.requires_grad = True
        p22.requires_grad = True

        pred_loss, pred_loss_norm = TestChamfer.chamfer_distance_naive(
            p1, p2, x_normals=p1_normals, y_normals=p2_normals
        )

        # point_reduction = None
        loss, loss_norm = chamfer_distance(
            p11,
            p22,
            x_normals=p1_normals,
            y_normals=p2_normals,
            batch_reduction=None,
            point_reduction=None,
            single_directional=True,
        )

        self.assertClose(loss, pred_loss[0])
        self.assertClose(loss_norm, pred_loss_norm[0])

        # Check gradients
        self._check_gradients(
            loss, loss_norm, pred_loss[0], pred_loss_norm[0], p1, p11, p2, p22
        )

    def _check_gradients(
        self,
        loss,
        loss_norm,
        pred_loss,
        pred_loss_norm,
        x1,
        x2,
        y1,
        y2,
        xn1=None,  # normals
        xn2=None,  # normals
        yn1=None,  # normals
        yn2=None,  # normals
        lengths1=None,
        lengths2=None,
    ):
        """
        x1 and x2 can have different types based on the leaf node used in the calculation:
        e.g. x1 may be a list of tensors whereas x2 is a padded tensor.
        This also applies for the pairs: (y1, y2), (xn1, xn2), (yn1, yn2).
        """
        grad_loss = torch.rand(loss.shape, device=loss.device, dtype=loss.dtype)

        # Loss for normals is optional. Iniitalize to 0.
        norm_loss_term = pred_norm_loss_term = 0.0
        if loss_norm is not None and pred_loss_norm is not None:
            grad_normals = torch.rand(
                loss_norm.shape, device=loss.device, dtype=loss.dtype
            )
            norm_loss_term = loss_norm * grad_normals
            pred_norm_loss_term = pred_loss_norm * grad_normals

        l1 = (loss * grad_loss) + norm_loss_term
        l1.sum().backward()
        l2 = (pred_loss * grad_loss) + pred_norm_loss_term
        l2.sum().backward()

        self._check_grad_by_type(x1, x2, lengths1)
        self._check_grad_by_type(y1, y2, lengths2)

        # If leaf nodes for normals are passed in, check their gradients.
        if all(n is not None for n in [xn1, xn2, yn1, yn2]):
            self._check_grad_by_type(xn1, xn2, lengths1)
            self._check_grad_by_type(yn1, yn2, lengths2)

    def _check_grad_by_type(self, x1, x2, lengths=None):
        """
        x1 and x2 can be of different types e.g. list or tensor - compare appropriately
        based on the types.
        """
        error_msg = "All values for gradient checks must be tensors or lists of tensors"

        if all(isinstance(p, list) for p in [x1, x2]):
            # Lists of tensors
            for i in range(len(x1)):
                self.assertClose(x1[i].grad, x2[i].grad)
        elif isinstance(x1, list) and torch.is_tensor(x2):
            self.assertIsNotNone(lengths)  # lengths is required

            # List of tensors vs padded tensor
            for i in range(len(x1)):
                self.assertClose(x1[i].grad, x2.grad[i, : lengths[i]], atol=1e-7)
                self.assertTrue(x2.grad[i, lengths[i] :].sum().item() == 0.0)
        elif all(torch.is_tensor(p) for p in [x1, x2]):
            # Two tensors
            self.assertClose(x1.grad, x2.grad)
        else:
            raise ValueError(error_msg)

    def test_chamfer_joint_reduction(self):
        """
        Compare output of vectorized chamfer loss with naive implementation
        when batch_reduction in ["mean", "sum"] and
        point_reduction in ["mean", "sum"].
        """
        N, max_P1, max_P2 = 7, 10, 18
        device = get_random_cuda_device()

        points_normals = TestChamfer.init_pointclouds(N, max_P1, max_P2, device)
        p1 = points_normals.p1
        p2 = points_normals.p2
        p1_normals = points_normals.n1
        p2_normals = points_normals.n2
        weights = points_normals.weights

        P1 = p1.shape[1]
        P2 = p2.shape[1]

        pred_loss, pred_loss_norm = TestChamfer.chamfer_distance_naive(
            p1, p2, x_normals=p1_normals, y_normals=p2_normals
        )

        # batch_reduction = "sum", point_reduction = "sum".
        loss, loss_norm = chamfer_distance(
            p1,
            p2,
            x_normals=p1_normals,
            y_normals=p2_normals,
            weights=weights,
            batch_reduction="sum",
            point_reduction="sum",
        )
        pred_loss[0] *= weights.view(N, 1)
        pred_loss[1] *= weights.view(N, 1)
        pred_loss_sum = pred_loss[0].sum(1) + pred_loss[1].sum(1)  # point sum
        pred_loss_sum = pred_loss_sum.sum()  # batch sum
        self.assertClose(loss, pred_loss_sum)

        pred_loss_norm[0] *= weights.view(N, 1)
        pred_loss_norm[1] *= weights.view(N, 1)
        pred_loss_norm_sum = pred_loss_norm[0].sum(1) + pred_loss_norm[1].sum(
            1
        )  # point sum.
        pred_loss_norm_sum = pred_loss_norm_sum.sum()  # batch sum
        self.assertClose(loss_norm, pred_loss_norm_sum)

        # batch_reduction = "mean", point_reduction = "sum".
        loss, loss_norm = chamfer_distance(
            p1,
            p2,
            x_normals=p1_normals,
            y_normals=p2_normals,
            weights=weights,
            batch_reduction="mean",
            point_reduction="sum",
        )
        pred_loss_sum /= weights.sum()
        self.assertClose(loss, pred_loss_sum)

        pred_loss_norm_sum /= weights.sum()
        self.assertClose(loss_norm, pred_loss_norm_sum)

        # batch_reduction = "sum", point_reduction = "mean".
        loss, loss_norm = chamfer_distance(
            p1,
            p2,
            x_normals=p1_normals,
            y_normals=p2_normals,
            weights=weights,
            batch_reduction="sum",
            point_reduction="mean",
        )
        pred_loss_mean = pred_loss[0].sum(1) / P1 + pred_loss[1].sum(1) / P2
        pred_loss_mean = pred_loss_mean.sum()
        self.assertClose(loss, pred_loss_mean)

        pred_loss_norm_mean = (
            pred_loss_norm[0].sum(1) / P1 + pred_loss_norm[1].sum(1) / P2
        )
        pred_loss_norm_mean = pred_loss_norm_mean.sum()
        self.assertClose(loss_norm, pred_loss_norm_mean)

        # batch_reduction = "mean", point_reduction = "mean". This is the default.
        loss, loss_norm = chamfer_distance(
            p1,
            p2,
            x_normals=p1_normals,
            y_normals=p2_normals,
            weights=weights,
            batch_reduction="mean",
            point_reduction="mean",
        )
        pred_loss_mean /= weights.sum()
        self.assertClose(loss, pred_loss_mean)

        pred_loss_norm_mean /= weights.sum()
        self.assertClose(loss_norm, pred_loss_norm_mean)

        # Error when batch_reduction is not in ["mean", "sum"] or None.
        with self.assertRaisesRegex(ValueError, "batch_reduction must be one of"):
            chamfer_distance(p1, p2, weights=weights, batch_reduction="max")

        # Error when point_reduction is not in ["mean", "sum"] or None.
        with self.assertRaisesRegex(ValueError, "point_reduction must be one of"):
            chamfer_distance(p1, p2, weights=weights, point_reduction="max")

    def test_incorrect_weights(self):
        N, P1, P2 = 16, 64, 128
        device = get_random_cuda_device()
        p1 = torch.rand(
            (N, P1, 3), dtype=torch.float32, device=device, requires_grad=True
        )
        p2 = torch.rand(
            (N, P2, 3), dtype=torch.float32, device=device, requires_grad=True
        )

        weights = torch.zeros((N,), dtype=torch.float32, device=device)
        loss, loss_norm = chamfer_distance(
            p1, p2, weights=weights, batch_reduction="mean"
        )
        self.assertClose(loss.cpu(), torch.zeros(()))
        self.assertTrue(loss.requires_grad)
        self.assertClose(loss_norm.cpu(), torch.zeros(()))
        self.assertTrue(loss_norm.requires_grad)

        loss, loss_norm = chamfer_distance(
            p1, p2, weights=weights, batch_reduction=None
        )
        self.assertClose(loss.cpu(), torch.zeros((N, N)))
        self.assertTrue(loss.requires_grad)
        self.assertClose(loss_norm.cpu(), torch.zeros((N, N)))
        self.assertTrue(loss_norm.requires_grad)

        weights = torch.ones((N,), dtype=torch.float32, device=device) * -1
        with self.assertRaises(ValueError):
            loss, loss_norm = chamfer_distance(p1, p2, weights=weights)

        weights = torch.zeros((N - 1,), dtype=torch.float32, device=device)
        with self.assertRaises(ValueError):
            loss, loss_norm = chamfer_distance(p1, p2, weights=weights)

    def test_incorrect_inputs(self):
        N, P1, P2 = 7, 10, 18
        device = get_random_cuda_device()
        points_normals = TestChamfer.init_pointclouds(N, P1, P2, device)
        p1 = points_normals.p1
        p2 = points_normals.p2
        p1_normals = points_normals.n1

        # Normals of wrong shape
        with self.assertRaisesRegex(ValueError, "Expected normals to be of shape"):
            chamfer_distance(p1, p2, x_normals=p1_normals[None])

        # Points of wrong shape
        with self.assertRaisesRegex(ValueError, "Expected points to be of shape"):
            chamfer_distance(p1[None], p2)

        # Lengths of wrong shape
        with self.assertRaisesRegex(ValueError, "Expected lengths to be of shape"):
            chamfer_distance(p1, p2, x_lengths=torch.tensor([1, 2, 3], device=device))

        # Points are not a tensor or Pointclouds
        with self.assertRaisesRegex(ValueError, "Pointclouds objects or torch.Tensor"):
            chamfer_distance(x=[1, 1, 1], y=[1, 1, 1])

    def test_invalid_norm(self):
        N, P1, P2 = 7, 10, 18
        device = get_random_cuda_device()
        points_normals = TestChamfer.init_pointclouds(N, P1, P2, device)
        p1 = points_normals.p1
        p2 = points_normals.p2

        with self.assertRaisesRegex(ValueError, "Support for 1 or 2 norm."):
            chamfer_distance(p1, p2, norm=0)

        with self.assertRaisesRegex(ValueError, "Support for 1 or 2 norm."):
            chamfer_distance(p1, p2, norm=3)

    def test_empty_clouds(self):
        # Check that point_reduction doesn't divide by zero
        points1 = Pointclouds(points=[torch.zeros(0, 3), torch.zeros(10, 3)])
        points2 = Pointclouds(points=torch.ones(2, 40, 3))
        loss, _ = chamfer_distance(points1, points2, batch_reduction=None)
        self.assertClose(loss, torch.tensor([0.0, 6.0]))

        # Check that batch_reduction doesn't divide by zero
        loss2, _ = chamfer_distance(Pointclouds([]), Pointclouds([]))
        self.assertClose(loss2, torch.tensor(0.0))

    @staticmethod
    def chamfer_with_init(
        batch_size: int,
        P1: int,
        P2: int,
        return_normals: bool,
        homogeneous: bool,
        device="cpu",
    ):
        points_normals = TestChamfer.init_pointclouds(batch_size, P1, P2, device=device)
        l1 = points_normals.p1_lengths
        l2 = points_normals.p2_lengths
        if homogeneous:
            # Set lengths to None so in Chamfer it assumes
            # there is no padding.
            l1 = l2 = None

        torch.cuda.synchronize()

        def loss():
            loss, loss_normals = chamfer_distance(
                points_normals.p1,
                points_normals.p2,
                x_lengths=l1,
                y_lengths=l2,
                x_normals=points_normals.n1,
                y_normals=points_normals.n2,
                weights=points_normals.weights,
            )
            torch.cuda.synchronize()

        return loss

    @staticmethod
    def chamfer_naive_with_init(
        batch_size: int, P1: int, P2: int, return_normals: bool, device="cpu"
    ):
        points_normals = TestChamfer.init_pointclouds(batch_size, P1, P2, device=device)
        torch.cuda.synchronize()

        def loss():
            loss, loss_normals = TestChamfer.chamfer_distance_naive(
                points_normals.p1,
                points_normals.p2,
                x_normals=points_normals.n1,
                y_normals=points_normals.n2,
            )
            torch.cuda.synchronize()

        return loss