under test, not sure no errors

ixformer_sdk/inference/functions/softmax.py

@@ -0,0 +1,33 @@
+from typing import Union
+
+import ixformer._C as ops
+import torch
+from torch.autograd.function import Function, FunctionCtx
+
+__all__ = ["softmax", "ref_softmax"]
+
+
+def ref_softmax(input: torch.Tensor, dim: int = None, _stacklevel: int = 3, dtype=None):
+    out = torch.nn.functional.softmax(
+        input, dim=dim, _stacklevel=_stacklevel, dtype=dtype
+    )
+    return out
+
+
+def softmax(input: torch.Tensor, dim=None, _stacklevel=3, dtype=None):
+    
+    """
+    Args:
+        input:              (...)                                           torch.float16
+        dim:                                                                int
+            要进行softmax的维度,目前只支持最后一维， dim==-1 or dim == input.dim()-1
+        _stacklevel:                                                        int
+            这个参数只是为了与pytorch中对齐。 stacklevel is used in python to indicate warning mechanism how far up the stack it has to go to find the line that called the function which issued the warning.
+        dtype:                                                              torch.float16                        
+    Returns:
+        Tensor:             (...)                                           torch.float16
+    """    
+    output = torch.empty_like(input)
+    ops.infer.softmax(input, output, dim)
+    output = output.to(dtype)
+    return output