Add tangent operator (#29207)

As the title

paddle/fluid/operators/activation_op.cc

@@ -249,6 +249,15 @@ $$out = cos(x)$$
 
 )DOC";
 
+UNUSED constexpr char TanDoc[] = R"DOC(
+Tangent Operator. Computes tangent of x element-wise.
+
+Input range is `(k*pi-pi/2, k*pi+pi/2)` and output range is `(-inf, inf)`.
+
+$$out = tan(x)$$
+
+)DOC";
+
 UNUSED constexpr char SinDoc[] = R"DOC(
 Sine Activation Operator.
 
@@ -709,6 +718,7 @@ REGISTER_ACTIVATION_OP_MAKER(Abs, AbsDoc);
 REGISTER_ACTIVATION_OP_MAKER(Ceil, CeilDoc);
 REGISTER_ACTIVATION_OP_MAKER(Floor, FloorDoc);
 REGISTER_ACTIVATION_OP_MAKER(Cos, CosDoc);
+REGISTER_ACTIVATION_OP_MAKER(Tan, TanDoc);
 REGISTER_ACTIVATION_OP_MAKER(Sin, SinDoc);
 REGISTER_ACTIVATION_OP_MAKER(Sinh, SinhDoc);
 REGISTER_ACTIVATION_OP_MAKER(Cosh, CoshDoc);

paddle/fluid/operators/activation_op.h

@@ -584,6 +584,39 @@ struct SinFunctor : public BaseActivationFunctor<T> {
   }
 };
 
+template <typename T>
+struct Tangent {
+  HOSTDEVICE T operator()(const T& val) const { return tan(val); }
+};
+
+template <>
+struct Tangent<platform::float16> {
+  HOSTDEVICE platform::float16 operator()(const platform::float16& val) const {
+    return platform::float16(tan(static_cast<float>(val)));
+  }
+};
+
+// Tangent'(x) = -Tangent(x)
+template <typename T>
+struct TanGradFunctor : public BaseActivationFunctor<T> {
+  template <typename Device, typename X, typename Out, typename dOut,
+            typename dX>
+  void operator()(Device d, X x, Out out, dOut dout, dX dx) const {
+    dx.device(d) = dout / x.unaryExpr(Cosine<T>()).square();
+  }
+
+  static constexpr ActBwdOpFwdDeps FwdDeps() { return kDepX; }
+};
+
+// Tangent(x) = tan(x)
+template <typename T>
+struct TanFunctor : public BaseActivationFunctor<T> {
+  template <typename Device, typename X, typename Out>
+  void operator()(Device d, X x, Out out) const {
+    out.device(d) = x.unaryExpr(Tangent<T>());
+  }
+};
+
 template <typename T>
 struct Sinh {
   HOSTDEVICE T operator()(const T& val) const { return sinh(val); }
@@ -1942,6 +1975,7 @@ struct LogGradGradFunctor : public BaseActivationFunctor<T> {
   __macro(ceil, Ceil, CeilFunctor, ZeroGradFunctor);                          \
   __macro(floor, Floor, FloorFunctor, ZeroGradFunctor);                       \
   __macro(cos, Cos, CosFunctor, CosGradFunctor);                              \
+  __macro(tan, Tan, TanFunctor, TanGradFunctor);                              \
   __macro(acos, Acos, AcosFunctor, AcosGradFunctor);                          \
   __macro(sin, Sin, SinFunctor, SinGradFunctor);                              \
   __macro(asin, Asin, AsinFunctor, AsinGradFunctor);                          \

python/paddle/__init__.py

@@ -134,6 +134,7 @@ from .tensor.math import asin  #DEFINE_ALIAS
 from .tensor.math import atan  #DEFINE_ALIAS
 from .tensor.math import ceil  #DEFINE_ALIAS
 from .tensor.math import cos  #DEFINE_ALIAS
+from .tensor.math import tan  #DEFINE_ALIAS
 from .tensor.math import cosh  #DEFINE_ALIAS
 from .tensor.math import cumsum  #DEFINE_ALIAS
 # from .tensor.math import elementwise_add  #DEFINE_ALIAS

python/paddle/fluid/layers/ops.py

@@ -43,6 +43,7 @@ __unary_func__ = [
     'ceil',
     'floor',
     'cos',
+    'tan',
     'acos',
     'sin',
     'sinh',
@@ -244,6 +245,19 @@ Examples:
 
 """)
 
+add_sample_code(globals()["tan"], r"""
+Examples:
+    .. code-block:: python
+
+        import paddle
+
+        x = paddle.to_tensor([-0.4, -0.2, 0.1, 0.3])
+        out = paddle.tan(x)
+        print(out)
+        # [-0.42279324, -0.20271005, 0.10033467, 0.30933627]
+
+""")
+
 add_sample_code(globals()["acos"], r"""
 Examples:
     .. code-block:: python

python/paddle/tensor/__init__.py

@@ -104,6 +104,7 @@ from .math import asin  #DEFINE_ALIAS
 from .math import atan  #DEFINE_ALIAS
 from .math import ceil  #DEFINE_ALIAS
 from .math import cos  #DEFINE_ALIAS
+from .math import tan  #DEFINE_ALIAS
 from .math import cosh  #DEFINE_ALIAS
 from .math import cumsum  #DEFINE_ALIAS
 # from .math import elementwise_add  #DEFINE_ALIAS

python/paddle/tensor/math.py

@@ -33,6 +33,7 @@ from ..fluid.layers import acos    #DEFINE_ALIAS
 from ..fluid.layers import asin    #DEFINE_ALIAS
 from ..fluid.layers import ceil    #DEFINE_ALIAS
 from ..fluid.layers import cos    #DEFINE_ALIAS
+from ..fluid.layers import tan    #DEFINE_ALIAS
 from ..fluid.layers import sinh    #DEFINE_ALIAS
 from ..fluid.layers import cosh    #DEFINE_ALIAS
 # from ..fluid.layers import elementwise_add    #DEFINE_ALIAS