Add torch_meshgrid wrapper due to PyTorch change (open-mmlab#2044)

* Add torch_meshgrid_ij wrapper due to PyTorch change

* Update torch_meshgrid name/doc/version implementation

* Make imports local

* add ut

* ignore ut when torch is not available

Co-authored-by: zhouzaida <zhouzaida@163.com>

.github/workflows/build.yml

@@ -45,7 +45,22 @@ jobs:
       - name: Run unittests and generate coverage report
         run: |
           pip install -r requirements/test.txt
-          pytest tests/ --ignore=tests/test_runner --ignore=tests/test_device/test_ipu --ignore=tests/test_optimizer.py --ignore=tests/test_cnn --ignore=tests/test_parallel.py --ignore=tests/test_ops --ignore=tests/test_load_model_zoo.py --ignore=tests/test_utils/test_logging.py --ignore=tests/test_image/test_io.py --ignore=tests/test_utils/test_registry.py --ignore=tests/test_utils/test_parrots_jit.py --ignore=tests/test_utils/test_trace.py --ignore=tests/test_utils/test_hub.py --ignore=tests/test_device/test_mlu/test_mlu_parallel.py
+          pytest tests/ \
+              --ignore=tests/test_runner \
+              --ignore=tests/test_device/test_ipu \
+              --ignore=tests/test_optimizer.py \
+              --ignore=tests/test_cnn \
+              --ignore=tests/test_parallel.py \
+              --ignore=tests/test_ops \
+              --ignore=tests/test_load_model_zoo.py \
+              --ignore=tests/test_utils/test_logging.py \
+              --ignore=tests/test_image/test_io.py \
+              --ignore=tests/test_utils/test_registry.py \
+              --ignore=tests/test_utils/test_parrots_jit.py \
+              --ignore=tests/test_utils/test_trace.py \
+              --ignore=tests/test_utils/test_hub.py \
+              --ignore=tests/test_device/test_mlu/test_mlu_parallel.py \
+              --ignore=tests/test_utils/test_torch_ops.py
 
   build_without_ops:
     runs-on: ubuntu-18.04

mmcv/utils/__init__.py

@@ -53,6 +53,7 @@
     # yapf: enable
     from .registry import Registry, build_from_cfg
     from .seed import worker_init_fn
+    from .torch_ops import torch_meshgrid
     from .trace import is_jit_tracing
     __all__ = [
         'Config', 'ConfigDict', 'DictAction', 'collect_env', 'get_logger',
@@ -74,5 +75,6 @@
         'assert_params_all_zeros', 'check_python_script',
         'is_method_overridden', 'is_jit_tracing', 'is_rocm_pytorch',
         '_get_cuda_home', 'load_url', 'has_method', 'IS_CUDA_AVAILABLE',
-        'worker_init_fn', 'IS_MLU_AVAILABLE', 'IS_IPU_AVAILABLE'
+        'worker_init_fn', 'IS_MLU_AVAILABLE', 'IS_IPU_AVAILABLE',
+        'torch_meshgrid'
     ]

mmcv/utils/torch_ops.py

@@ -0,0 +1,29 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+import torch
+
+from .parrots_wrapper import TORCH_VERSION
+from .version_utils import digit_version
+
+_torch_version_meshgrid_indexing = (
+    'parrots' not in TORCH_VERSION
+    and digit_version(TORCH_VERSION) >= digit_version('1.10.0a0'))
+
+
+def torch_meshgrid(*tensors):
+    """A wrapper of torch.meshgrid to compat different PyTorch versions.
+
+    Since PyTorch 1.10.0a0, torch.meshgrid supports the arguments ``indexing``.
+    So we implement a wrapper here to avoid warning when using high-version
+    PyTorch and avoid compatibility issues when using previous versions of
+    PyTorch.
+
+    Args:
+        tensors (List[Tensor]): List of scalars or 1 dimensional tensors.
+
+    Returns:
+        Sequence[Tensor]: Sequence of meshgrid tensors.
+    """
+    if _torch_version_meshgrid_indexing:
+        return torch.meshgrid(*tensors, indexing='ij')
+    else:
+        return torch.meshgrid(*tensors)  # Uses indexing='ij' by default

tests/test_utils/test_torch_ops.py

@@ -0,0 +1,15 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+import pytest
+import torch
+
+from mmcv.utils import torch_meshgrid
+
+
+def test_torch_meshgrid():
+    # torch_meshgrid should not throw warning
+    with pytest.warns(None) as record:
+        x = torch.tensor([1, 2, 3])
+        y = torch.tensor([4, 5, 6])
+        grid_x, grid_y = torch_meshgrid(x, y)
+
+    assert len(record) == 0