Support slicing a shallow copy of a 3-d tensor (#83)

sherpa-onnx/csrc/slice.h

@@ -0,0 +1,29 @@
+// sherpa-onnx/csrc/slice.h
+//
+// Copyright (c)  2023  Xiaomi Corporation
+#ifndef SHERPA_ONNX_CSRC_SLICE_H_
+#define SHERPA_ONNX_CSRC_SLICE_H_
+
+#include "onnxruntime_cxx_api.h"  // NOLINT
+
+namespace sherpa_onnx {
+
+/** Get a shallow copy by slicing v.
+ *
+ * It returns v[dim0, dim1_start:dim1_end]
+ *
+ * @param v A 3-D tensor. Its data type is T.
+ * @param dim0  Start index of the first dimension..
+ * @param dim1_start Start index of the second dimension.
+ * @param dim1_end  End index of the second dimension.
+ *
+ * @return Return a 2-D tensor of shape (dim1_end-dim1_start, v.shape[2])
+ *
+ * @caution: The returned tensor is a shallow copy of `v`!
+ */
+template <typename T = float>
+Ort::Value Slice(const Ort::Value *v, int32_t dim0, int32_t dim1_start,
+                 int32_t dim1_end);
+}  // namespace sherpa_onnx
+
+#endif  // SHERPA_ONNX_CSRC_SLICE_H_