[feat] add erf back

Author: Yin Hongyun

diopi_test/python/configs/diopi_configs.py

@@ -666,6 +666,24 @@
             ],
         ),
     ),
+    
+    'erf': dict(
+        name=['erf'],
+        interface=['torch'],
+        dtype=[np.float16, np.float32, np.float64],
+        tensor_para=dict(
+            gen_fn='Genfunc.randn',
+            args=[
+                {
+                    "ins": ['input'],
+                    "requires_grad": [True],
+                    "shape": ((), (1, ), (1024,), (364800, 4), (2, 128, 3072),
+                              (256, 128, 3, 3),
+                              (2, 31, 512, 6, 40), (0,), (16, 0)),
+                },
+            ],
+        ),
+    ),
 
     'relu_no_contiguous': dict(
         name=["relu"],

diopi_test/python/conformance/diopi_functions.py

@@ -540,6 +540,15 @@ def log1p(input, inplace=False) -> Tensor:
     return unary_op(input, inplace, "diopiLog1p", promote_type(input, Dtype.float32))
 
 
+def erf_backward(input, grad_outputs, **kwargs) -> Tensor:
+    assert len(grad_outputs) == 1, "only accept 1 gradient to do backward"
+    grad_input = raw_like(input)
+    func = check_function("diopiErfBackward")
+    ret = func(input.context(), grad_input, grad_outputs[0], input)
+    check_returncode(ret)
+    return {"input": grad_input} if grad_input.requires_grad else {}
+
+
 def erf(input, inplace=False) -> Tensor:
     return unary_op(input, inplace, "diopiErf", promote_type(input, Dtype.float32))
 

impl/torch/functions/functions.cpp

@@ -1600,6 +1600,19 @@ diopiError_t diopiErf(diopiContextHandle_t ctx, diopiTensorHandle_t out, diopiCo
     return diopiSuccess;
 }
 
+diopiError_t diopiErfBackward(diopiContextHandle_t ctx, diopiConstTensorHandle_t grad_in, diopiTensorHandle_t grad_out, 
+                              diopiConstTensorHandle_t input){
+    impl::aten::setCurStream(ctx);
+    auto atGradIn = impl::aten::buildATen(grad_in);
+    auto atGradOut = impl::aten::buildATen(grad_out);
+    auto atInput = impl::aten::buildATen(input);
+    auto local_grad = (2.0 / std::sqrt(M_PI)) * at::exp(-atInput * atInput);
+    atGradIn.copy_(atGradOut * local_grad);
+
+    return diopiSuccess;
+}
+
+
 diopiError_t diopiErfInp(diopiContextHandle_t ctx, diopiTensorHandle_t input) {
     impl::aten::setCurStream(ctx);
     auto atInput = impl::aten::buildATen(input);

proto/include/diopi/functions.h

@@ -241,6 +241,12 @@ DIOPI_API diopiError_t diopiRelu(diopiContextHandle_t ctx, diopiTensorHandle_t o
  */
 DIOPI_API diopiError_t diopiReluBackward(diopiContextHandle_t ctx, diopiConstTensorHandle_t grad_in, diopiTensorHandle_t grad_out, diopiConstTensorHandle_t input);
 
+/**
+ * @brief Comput the gradient of the error function.
+ */
+DIOPI_API diopiError_t diopiErfBackward(diopiContextHandle_t ctx, diopiConstTensorHandle_t grad_in, diopiTensorHandle_t grad_out, diopiConstTensorHandle_t input);
+
+
 /**
  * @brief The in-place version of diopiRelu().
  * @param[in] ctx Context environment.