add rsqrt yaml and unittest (#41443)

python/paddle/fluid/tests/unittests/test_activation_op.py

@@ -1023,6 +1023,7 @@ class TestSqrtBF16(OpTest):
 class TestRsqrt(TestActivation):
     def setUp(self):
         self.op_type = "rsqrt"
+        self.python_api = paddle.rsqrt
         self.init_dtype()
 
         np.random.seed(1024)
@@ -1035,7 +1036,8 @@ class TestRsqrt(TestActivation):
     def test_check_grad(self):
         if self.dtype == np.float16:
             return
-        self.check_grad(['X'], 'Out', max_relative_error=0.0005)
+        self.check_grad(
+            ['X'], 'Out', max_relative_error=0.0005, check_eager=True)
 
 
 class TestAbs(TestActivation):

python/paddle/utils/code_gen/api.yaml

@@ -1544,6 +1544,16 @@
     func : round
   backward : round_grad
 
+- api : rsqrt
+  args : (Tensor x)
+  output : Tensor(out)
+  infer_meta :
+    func : UnchangedInferMeta
+  kernel :
+    func : rsqrt
+  inplace : (x -> out)
+  backward : rsqrt_grad
+
 - api : scale
   args : (Tensor x, Scalar scale, float bias, bool bias_after_scale)
   output : Tensor

python/paddle/utils/code_gen/backward.yaml

@@ -1133,6 +1133,16 @@
   kernel :
     func : round_grad
 
+- backward_api : rsqrt_grad
+  forward : rsqrt (Tensor x) -> Tensor(out)
+  args : (Tensor out, Tensor out_grad)
+  output : Tensor(x_grad)
+  infer_meta :
+    func : UnchangedInferMeta
+    param : [out]
+  kernel :
+    func : rsqrt_grad
+
 - backward_api : scale_grad
   forward : scale (Tensor x, Scalar scale, float bias, bool bias_after_scale) -> Tensor(out)
   args : (Tensor out_grad, Scalar scale=1.0, float bias=0.0, bool bias_after_scale=true)