From 23c26277086c78704a17f0dae86da947816320c0 Mon Sep 17 00:00:00 2001
From: George Gekov <george.gekov@arm.com>
Date: Mon, 16 Aug 2021 11:32:10 +0100
Subject: MLECO-2079 Adding the C++ KWS example

Signed-off-by: Eanna O Cathain <eanna.ocathain@arm.com>
Change-Id: I81899bbfaada32f478c2e2fc6441eabb94d8d0fc
---
 samples/common/src/Audio/MathUtils.cpp | 111 +++++++++++++++++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 samples/common/src/Audio/MathUtils.cpp

(limited to 'samples/common/src/Audio/MathUtils.cpp')

diff --git a/samples/common/src/Audio/MathUtils.cpp b/samples/common/src/Audio/MathUtils.cpp
new file mode 100644
index 0000000000..d91b5098e1
--- /dev/null
+++ b/samples/common/src/Audio/MathUtils.cpp
@@ -0,0 +1,111 @@
+//
+// Copyright © 2021 Arm Ltd and Contributors. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#include "MathUtils.hpp"
+#include <vector>
+#include <cmath>
+#include <cstdio>
+
+void MathUtils::FftF32(std::vector<float>& input,
+                       std::vector<float>& fftOutput)
+{
+    const int inputLength = input.size();
+
+    for (int k = 0; k <= inputLength / 2; k++)
+    {
+        float sumReal = 0, sumImag = 0;
+
+        for (int t = 0; t < inputLength; t++)
+        {
+            float angle = 2 * M_PI * t * k / inputLength;
+            sumReal += input[t] * cosf(angle);
+            sumImag += -input[t] * sinf(angle);
+        }
+
+        /* Arrange output to [real0, realN/2, real1, im1, real2, im2, ...] */
+        if (k == 0)
+        {
+            fftOutput[0] = sumReal;
+        }
+        else if (k == inputLength / 2)
+        {
+            fftOutput[1] = sumReal;
+        }
+        else
+        {
+            fftOutput[k*2] = sumReal;
+            fftOutput[k*2 + 1] = sumImag;
+        };
+    }
+}
+
+float MathUtils::DotProductF32(const float* srcPtrA, float* srcPtrB,
+                               const int srcLen)
+{
+    float output = 0.f;
+
+    for (int i = 0; i < srcLen; ++i)
+    {
+        output += *srcPtrA++ * *srcPtrB++;
+    }
+    return output;
+}
+
+bool MathUtils::ComplexMagnitudeSquaredF32(const float* ptrSrc,
+                                           int srcLen,
+                                           float* ptrDst,
+                                           int dstLen)
+{
+    if (dstLen < srcLen/2)
+    {
+        printf("dstLen must be greater than srcLen/2");
+        return false;
+    }
+
+    for (int j = 0; j < dstLen; ++j)
+    {
+        const float real = *ptrSrc++;
+        const float im = *ptrSrc++;
+        *ptrDst++ = real*real + im*im;
+    }
+    return true;
+}
+
+void MathUtils::VecLogarithmF32(std::vector <float>& input,
+                                std::vector <float>& output)
+{
+    for (auto in = input.begin(), out = output.begin();
+         in != input.end(); ++in, ++out)
+    {
+        *out = logf(*in);
+    }
+}
+
+float MathUtils::MeanF32(const float* ptrSrc, const uint32_t srcLen)
+{
+    if (!srcLen)
+    {
+        return 0.f;
+    }
+
+    float acc = std::accumulate(ptrSrc, ptrSrc + srcLen, 0.0);
+    return acc/srcLen;
+}
+
+float MathUtils::StdDevF32(const float* ptrSrc, uint32_t srcLen, float mean)
+{
+    if (!srcLen)
+    {
+        return 0.f;
+    }
+    auto VarianceFunction = [mean, srcLen](float acc, const float value) {
+        return acc + (((value - mean) * (value - mean))/ srcLen);
+    };
+
+    float acc = std::accumulate(ptrSrc, ptrSrc + srcLen, 0.0,
+                                VarianceFunction);
+    return sqrtf(acc);
+}
+
-- 
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