IVGCVSW-2607 Implement Input range override mechanism

 * Added the OverrideInputRange method to the Quantizer API
 * Created OverrideInputRangeVisitor to implement the override mechanism
 * Moved the quantizer utility functions to the new NetworkQuantizerUtils files
 * Moved the map of quantization ranges out of the StaticRangeVisitor
   and into the NetworkQuantizer
 * Added unit tests
 * Code refactoring and cleanup

Change-Id: I9c1d006c1b6a35fbc04584a832fbe489f8f9276d
Signed-off-by: Matteo Martincigh <matteo.martincigh@arm.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/src/armnn/NetworkQuantizerUtils.hpp b/src/armnn/NetworkQuantizerUtils.hpp
new file mode 100644
index 0000000000..458d21a974
--- /dev/null
+++ b/src/armnn/NetworkQuantizerUtils.hpp
@@ -0,0 +1,56 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#pragma once
+
+#include <armnn/Tensor.hpp>
+#include <armnn/TypesUtils.hpp>
+#include <armnn/ILayerVisitor.hpp>
+
+#include <utility>
+#include <limits>
+
+#include <boost/assert.hpp>
+
+namespace armnn
+{
+
+std::pair<int, float> ComputeQAsymmParams(int numBits, double min, double max);
+
+template<typename srcType>
+void Quantize(const srcType* src, uint8_t* dst, size_t numElements, float& scale, int& offset)
+{
+    BOOST_ASSERT(src);
+    BOOST_ASSERT(dst);
+
+    float min = std::numeric_limits<srcType>::max();
+    float max = std::numeric_limits<srcType>::lowest();
+    for (size_t i = 0; i < numElements; ++i)
+    {
+        min = std::min(min, src[i]);
+        max = std::max(max, src[i]);
+    }
+
+    auto qParams = ComputeQAsymmParams(8, min, max);
+    offset = qParams.first;
+    scale = qParams.second;
+    for (size_t i = 0; i < numElements; ++i)
+    {
+        dst[i] = armnn::Quantize<uint8_t>(src[i], scale, offset);
+    }
+}
+
+ConstTensor CreateQuantizedConst(const ConstTensor& tensor, std::vector<uint8_t>& backing);
+
+template <typename LayerContainer>
+void VisitLayers(const LayerContainer& layerContainer, ILayerVisitor& visitor)
+{
+    for (auto layer : layerContainer)
+    {
+        layer->Accept(visitor);
+    }
+}
+
+} // namespace armnn