[Function] Add slice function (#719)

* fix math functions

* add slice function

fastdeploy/function/slice.h

@@ -0,0 +1,41 @@
+// Copyright (c) 2022 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#pragma once
+
+#include "fastdeploy/core/fd_tensor.h"
+
+namespace fastdeploy {
+namespace function {
+
+/** This operator produces a slice of input along multiple axes.
+    @param x The input tensor.
+    @param axes Axes that starts and ends apply to.
+    @param starts If starts is a list or tuple, the elements of it should be
+      integers or Tensors with shape [1]. If starts is an Tensor, it should
+      be an 1-D Tensor. It represents starting indices of corresponding axis
+      in axes
+    @param ends If ends is a list or tuple, the elements of it should be
+      integers or Tensors with shape [1]. If ends is an Tensor, it should
+      be an 1-D Tensor . It represents ending indices of corresponding axis
+      in axes.
+    @param out The output tensor which stores the result.
+*/
+
+FASTDEPLOY_DECL void Slice(const FDTensor& x, const std::vector<int64_t>& axes,
+                           const std::vector<int64_t>& starts,
+                           const std::vector<int64_t>& ends, FDTensor* out);
+
+}  // namespace function
+}  // namespace fastdeploy