[tensor]build sharding spec to replace distspec in future. (#1405)

tests/test_tensor/test_sharding_spec.py

@@ -0,0 +1,24 @@
+import torch
+from colossalai.tensor.sharding_spec import _DimSpec, ShardingSpec
+from colossalai.device.device_mesh import DeviceMesh
+
+
+def test_sharding_spec():
+    physical_mesh_id = torch.arange(0, 16).reshape(2, 8)
+    mesh_shape = (4, 4)
+    # [[0, 1, 2, 3],
+    #  [4, 5, 6, 7],
+    #  [8, 9, 10,11],
+    #  [12,13,14,15]]
+    device_mesh = DeviceMesh(physical_mesh_id, mesh_shape)
+    entire_shape = torch.Size((4, 8, 6))
+    dim_partition_dict = {0: [0, 1]}
+    # DistSpec:
+    #     shard_sequence: S01,R,R
+    #     device_mesh_shape: (4, 4)
+    sharding_spec = ShardingSpec(device_mesh, entire_shape, dim_partition_dict)
+    assert str(sharding_spec.sharding_sequence) == "[S01, R, R]"
+
+
+if __name__ == '__main__':
+    test_sharding_spec()