# HG changeset patch
# User Chris Cannam
# Date 1471609600 -3600
# Node ID 109c3a2ad9304f517363a5cfb683f6569c04c700
# Parent  7cbf40306c10cd722cb4a8a71741fe42a52d79f3
Make use of new Vamp FFT interface. This reduces the runtime of the regression test from 5.7 to 2.2 seconds on this machine, but it does need the right version of the SDK, which is currently only available in the vampipe branch.

diff -r 7cbf40306c10 -r 109c3a2ad930 YinUtil.cpp
--- a/YinUtil.cpp	Fri Aug 19 12:00:13 2016 +0100
+++ b/YinUtil.cpp	Fri Aug 19 13:26:40 2016 +0100
@@ -38,7 +38,7 @@
     double delta ;
     int startPoint = 0;
     int endPoint = 0;
-    for (int i = 1; i < m_yinBufferSize; ++i) {
+    for (int i = 1; i < int(m_yinBufferSize); ++i) {
         yinBuffer[i] = 0;
         startPoint = m_yinBufferSize/2 - i/2;
         endPoint = startPoint + m_yinBufferSize;
@@ -52,21 +52,18 @@
 void 
 YinUtil::fastDifference(const double *in, double *yinBuffer) 
 {
-    
     // DECLARE AND INITIALISE
     // initialisation of most of the arrays here was done in a separate function,
     // with all the arrays as members of the class... moved them back here.
     
     size_t frameSize = 2 * m_yinBufferSize;
-    
-    double *audioTransformedReal = new double[frameSize];
-    double *audioTransformedImag = new double[frameSize];
-    double *nullImag = new double[frameSize];
+    size_t halfSize = m_yinBufferSize;
+
+    double *audioTransformedComplex = new double[frameSize + 2];
+    double *audioOutReal = new double[frameSize];
     double *kernel = new double[frameSize];
-    double *kernelTransformedReal = new double[frameSize];
-    double *kernelTransformedImag = new double[frameSize];
-    double *yinStyleACFReal = new double[frameSize];
-    double *yinStyleACFImag = new double[frameSize];
+    double *kernelTransformedComplex = new double[frameSize + 2];
+    double *yinStyleACFComplex = new double[frameSize + 2];
     double *powerTerms = new double[m_yinBufferSize];
     
     for (size_t j = 0; j < m_yinBufferSize; ++j)
@@ -77,14 +74,7 @@
     
     for (size_t j = 0; j < frameSize; ++j)
     {
-        nullImag[j] = 0.;
-        audioTransformedReal[j] = 0.;
-        audioTransformedImag[j] = 0.;
         kernel[j] = 0.;
-        kernelTransformedReal[j] = 0.;
-        kernelTransformedImag[j] = 0.;
-        yinStyleACFReal[j] = 0.;
-        yinStyleACFImag[j] = 0.;
     }
     
     // POWER TERM CALCULATION
@@ -96,43 +86,48 @@
 
     // now iteratively calculate all others (saves a few multiplications)
     for (size_t tau = 1; tau < m_yinBufferSize; ++tau) {
-        powerTerms[tau] = powerTerms[tau-1] - in[tau-1] * in[tau-1] + in[tau+m_yinBufferSize] * in[tau+m_yinBufferSize];  
+        powerTerms[tau] = powerTerms[tau-1] -
+            in[tau-1] * in[tau-1] +
+            in[tau+m_yinBufferSize] * in[tau+m_yinBufferSize];  
     }
 
     // YIN-STYLE AUTOCORRELATION via FFT
     // 1. data
-    Vamp::FFT::forward(frameSize, in, nullImag, audioTransformedReal, audioTransformedImag);
+    m_fft.forward(in, audioTransformedComplex);
     
     // 2. half of the data, disguised as a convolution kernel
     for (size_t j = 0; j < m_yinBufferSize; ++j) {
         kernel[j] = in[m_yinBufferSize-1-j];
     }
-    Vamp::FFT::forward(frameSize, kernel, nullImag, kernelTransformedReal, kernelTransformedImag);
+    m_fft.forward(kernel, kernelTransformedComplex);
 
     // 3. convolution via complex multiplication -- written into
-    for (size_t j = 0; j < frameSize; ++j) {
-        yinStyleACFReal[j] = audioTransformedReal[j]*kernelTransformedReal[j] - audioTransformedImag[j]*kernelTransformedImag[j]; // real
-        yinStyleACFImag[j] = audioTransformedReal[j]*kernelTransformedImag[j] + audioTransformedImag[j]*kernelTransformedReal[j]; // imaginary
+    for (size_t j = 0; j <= halfSize; ++j) {
+        yinStyleACFComplex[j*2] = // real
+            audioTransformedComplex[j*2] * kernelTransformedComplex[j*2] -
+            audioTransformedComplex[j*2+1] * kernelTransformedComplex[j*2+1];
+        yinStyleACFComplex[j*2+1] = // imaginary
+            audioTransformedComplex[j*2] * kernelTransformedComplex[j*2+1] +
+            audioTransformedComplex[j*2+1] * kernelTransformedComplex[j*2];
     }
-    Vamp::FFT::inverse(frameSize, yinStyleACFReal, yinStyleACFImag, audioTransformedReal, audioTransformedImag);
+
+    m_fft.inverse(yinStyleACFComplex, audioOutReal);
     
     // CALCULATION OF difference function
     // ... according to (7) in the Yin paper.
     for (size_t j = 0; j < m_yinBufferSize; ++j) {
-        // taking only the real part
-        yinBuffer[j] = powerTerms[0] + powerTerms[j] - 2 * audioTransformedReal[j+m_yinBufferSize-1];
+        yinBuffer[j] = powerTerms[0] + powerTerms[j] - 2 *
+            audioOutReal[j+m_yinBufferSize-1];
     }
-    delete [] audioTransformedReal;
-    delete [] audioTransformedImag;
-    delete [] nullImag;
+    delete [] audioTransformedComplex;
+    delete [] audioOutReal;
     delete [] kernel;
-    delete [] kernelTransformedReal;
-    delete [] kernelTransformedImag;
-    delete [] yinStyleACFReal;
-    delete [] yinStyleACFImag;
+    delete [] kernelTransformedComplex;
+    delete [] yinStyleACFComplex;
     delete [] powerTerms;
 }
 
+
 void 
 YinUtil::cumulativeDifference(double *yinBuffer)
 {    
@@ -298,7 +293,7 @@
                 minInd = tau;
             }
             currThreshInd = nThresholdInt-1;
-            while (thresholds[currThreshInd] > yinBuffer[tau] && currThreshInd > -1) {
+            while (currThreshInd > -1 && thresholds[currThreshInd] > yinBuffer[tau]) {
                 // std::cerr << distribution[currThreshInd] << std::endl;
                 peakProb[tau] += distribution[currThreshInd];
                 currThreshInd--;