IVGCVSW-3663 Add utility function to expand tensor dimension

Signed-off-by: Narumol Prangnawarat <narumol.prangnawarat@arm.com>
Change-Id: I54d2416be305db7d3fc15fb3123694ad6740b27d

1 files changed, 32 insertions, 0 deletions

diff --git a/src/armnnUtils/TensorUtils.cpp b/src/armnnUtils/TensorUtils.cpp
index c2fbbe0bcc..8baea78ab5 100644
--- a/src/armnnUtils/TensorUtils.cpp
+++ b/src/armnnUtils/TensorUtils.cpp
@@ -6,6 +6,10 @@
 #include "TensorUtils.hpp"
 #include <backendsCommon/ITensorHandle.hpp>
 
+#include <boost/assert.hpp>
+#include <boost/format.hpp>
+#include <boost/numeric/conversion/cast.hpp>
+
 namespace armnnUtils
 {
 
@@ -75,4 +79,32 @@ std::pair<float, float> FindMinMax(armnn::ITensorHandle* tensorHandle)
     return std::make_pair(min, max);
 }
 
+armnn::TensorShape ExpandDims(const armnn::TensorShape& tensorShape, int axis)
+{
+    unsigned int outputDim = tensorShape.GetNumDimensions() + 1;
+
+    if (axis < -boost::numeric_cast<int>(outputDim) || axis > boost::numeric_cast<int>(tensorShape.GetNumDimensions()))
+    {
+        throw armnn::InvalidArgumentException(
+            boost::str(boost::format("Invalid expansion axis %1% for %2%D input tensor. %3%") %
+                       axis %
+                       tensorShape.GetNumDimensions() %
+                       CHECK_LOCATION().AsString()));
+    }
+
+    if (axis < 0)
+    {
+        axis = boost::numeric_cast<int>(outputDim) + axis;
+    }
+
+    std::vector<unsigned int> outputShape;
+    for (unsigned int i = 0; i < tensorShape.GetNumDimensions(); ++i)
+    {
+        outputShape.push_back(tensorShape[i]);
+    }
+    outputShape.insert(outputShape.begin() + axis, 1);
+
+    return armnn::TensorShape(outputDim, outputShape.data());
+}
+
 }