[Fix](bangc-ops): support grad_voxel_feats zero element & fix constra…

[baicaixmj]

Thanks for your contribution and we appreciate it a lot.

1. Motivation

1. support grad_voxel_feats zero element
2. fix constraint description in header file
3. fix policy func on MLU370_S4

2. Modification

1. modified: bangc-ops/kernel_depends.toml
2. modified: bangc-ops/kernels/dynamic_point_to_voxel_backward/dynamic_point_to_voxel_backward.cpp
3. modified: bangc-ops/kernels/dynamic_point_to_voxel_backward/dynamic_point_to_voxel_backward.mlu
4. modified: bangc-ops/mlu_op.h

3. Test Report

If you want to know how to do operator testing, you can see GTest-User-Guide-zh.

3.1 Modification Details

3.1.1 Accuracy Acceptance Standard

For static threshold standard details, see: MLU-OPS Accuracy Acceptance Standard.

• diff3: diff3 <= 0

3.1.2 Operator Scheme checklist

No.	Details	Check Results
1	Supported hardware	MLU370 MLU590
2	Job types	U1、U2、U4、U8（看空闲资源）
3	Layouts	ARRAY
4	Whether multi-dimensions are supported	no
5	Whether element zero is supported	yes
6	Data type(half/float)	float
7	Whether there is size limit	grad_voxel_feats、voxel_feats、voxel_points_count的第一维度 dims[0] 都相等，且<= feats的第一维度 dims[0]；feats、point2voxel_map、grad_feats的第一维度 dims[0] 都相等； voxel_num 的维度为 1； grad_voxel_feats、feats、voxel_feats、grad_feats的第二维度 dims[1] 都相等； 5 * feats_desc->dims[0]+20 * feats_desc->dims[1]+sizeof(int) <= 640KB(MLU370) 或 384KB(MLU590)

3.1.3 New Feature Test

If you have checked the following items, please tick the relevant box.

• Data type test
• Multi-dimensional tensor test
• Layout test
• Different size/integer remainder end segment/alignment misalignment test
• Zero dimensional tensor test/zero element test
• stability test
• Multiple platform test
• Gen_case module test
• Nan/INF tests
• Bug fix tests
• For memory leak check details, seeGTest-User-Guide-zh.
• For code coverage check details, see: GTest-User-Guide-zh.
• For I/O calculation efficiency check details, see: MLU-OPS Performance Acceptance Standard.

3.1.4 Parameter Check

When a new operator is submitted, the test points are given and the test results are stated.

Test Point	Acceptance Standard	Test Result (Error Message)
Whether it conforms to the operator restriction	Normal error	通过
Whether illegal parameters are passed	Normal error	通过

3.2 Accuracy Test

For the cases used in the New Feature Test section, the features and the number of cases are recorded here. When multiple operations are tested, multiple tables are needed to include details of these operations.

Operation:

Test Point	Description	Quantity	Comment
Data type test	float	通过	[----------] Global test environment tear-down [ SUMMARY ] Total 200 cases of 1 op(s). ALL PASSED. [==========] 200 test cases from 1 test suite ran. (77973 ms total) [ PASSED ] 200 test cases.
Zero element test	Whether to support this test	通过	[2023-5-24 16:6:57] [MLUOP] [Vlog]:[DynamicPointToVoxelBackwardExecutor] call compute() Begin. [2023-5-24 16:6:57] [MLUOP] [Vlog]:[mluOpDynamicPointToVoxelBackward] Skip zero element tensor. [2023-5-24 16:6:57] [MLUOP] [Vlog]:[DynamicPointToVoxelBackwardExecutor] call compute() End.
Stability test	--gtest_repeat=NUM --thread=NUM	通过	./mluop_gtest --cases_dir=xxxx --gtest_repeat=100 --thread=100 [----------] Global test environment tear-down [ SUMMARY ] Total 20000 cases of 600 op(s). ALL PASSED. [==========] 6 test cases from 6 test suites ran. (2932 ms total) [ PASSED ] 6 test cases.
Mult-platform test	MLU370/MLU590	通过	MLU370: [----------] Global test environment tear-down [ SUMMARY ] Total 200 cases of 1 op(s). ALL PASSED. [==========] 200 test cases from 1 test suite ran. (19708 ms total) [ PASSED ] 200 test cases. MLU590: [----------] Global test environment tear-down [ SUMMARY ] Total 200 cases of 1 op(s). ALL PASSED. [==========] 200 test cases from 1 test suite ran. (21528 ms total) [ PASSED ] 200 test cases.
Nan/INF test	Whether to support this test	通过	[----------] Global test environment tear-down [ SUMMARY ] Total 18 cases of 1 op(s). ALL PASSED. [==========] 18 test cases from 1 test suite ran. (636 ms total) [ PASSED ] 18 test cases.
Memory leak check	Test result	通过	MLUOP_BUILD_ASAN_CHECK=ON ./build.sh --filter=dynamic_point_to_voxel_backward
Code coverage check	Test result	通过	dynamic_point_to_voxel_backward.mlu Line Coverage 98.7% 148 / 150 Functions 100.0 % 5 / 5

3.3 Performance Test

See MLU-OPS Performance Acceptance Standard for details.

Platform：MLU370

Operation	Mlu_hardware_time(us)	Mlu_interface_time(us)	Mlu_io_efficiency	Mlu_compute_efficiency	Mlu_workwpace_size(Bytes)	Data_type	Shape
dynamic_point_to_voxel_backward	10191	209.829	0.0076793	0.000208799	8.71576e+06	float	grad_feats:[17157, 127]
dynamic_point_to_voxel_backward	128	147.71	0.00499349	0.000178711	93696	float	grad_feats:[183, 128]

Platform：MLU590

Operation	Mlu_hardware_time(us)	Mlu_interface_time(us)	Mlu_io_efficiency	Mlu_compute_efficiency	Mlu_workwpace_size(Bytes)	Data_type	Shape
dynamic_point_to_voxel_backward	2230	138.001	0.00526411	0.00042409	8.71576e+06	float	grad_feats:[17157, 127]
dynamic_point_to_voxel_backward	26	91.098	0.0036875	0.000391026	93696	float	grad_feats:[183, 128]

3.4 Summary Analysis

1）MLU370上性能与真值相关
2）特征类tensor支持nan/inf，坐标类tensor是整型不支持nan/inf
3) 支持grad_voxel_feats/voxel_feats/voxel_points_count输入规模为0，此时grad_feats输出全0
4）MLU370_S4的cluster数量为6，最多可以起U4任务。