# HG changeset patch
# User Chris Cannam <cannam@all-day-breakfast.com>
# Date 1559221815 -3600
# Node ID 8d84e5d16314f256e94aaab5a1c69bff2dc6b5f5
# Parent  a72d98f8baa37c2faa6e67800adab6e7a6e701cb
Fix error in lower bins

diff -r a72d98f8baa3 -r 8d84e5d16314 dsp/chromagram/ConstantQ.cpp
--- a/dsp/chromagram/ConstantQ.cpp	Thu May 30 11:35:35 2019 +0100
+++ b/dsp/chromagram/ConstantQ.cpp	Thu May 30 14:10:15 2019 +0100
@@ -128,6 +128,9 @@
 	// Computing a hamming window
 	const unsigned hammingLength = (int) ceil( m_dQ * m_FS / ( m_FMin * pow(2,((double)(k))/(double)m_BPO)));
 
+//        cerr << "k = " << k << ", q = " << m_dQ << ", m_FMin = " << m_FMin << ", hammingLength = " << hammingLength << " (rounded up from " << (m_dQ * m_FS / ( m_FMin * pow(2,((double)(k))/(double)m_BPO))) << ")" << endl;
+        
+
         unsigned origin = m_FFTLength/2 - hammingLength/2;
 
 	for (unsigned i=0; i<hammingLength; i++) 
@@ -159,7 +162,7 @@
 	    const double squaredBin = squaredModule( transfHammingWindowRe[ j ], transfHammingWindowIm[ j ]);
 	    if (squaredBin <= squareThreshold) continue;
 		
-	    // Insert non-zero position indexes, doubled because they are floats
+	    // Insert non-zero position indexes
 	    sk->is.push_back(j);
 	    sk->js.push_back(k);
 
@@ -271,6 +274,7 @@
     {
 	const unsigned row = cqbin[i];
 	const unsigned col = fftbin[i];
+        if (col == 0) continue;
 	const double & r1  = real[i];
 	const double & i1  = imag[i];
 	const double & r2  = fftdata[ (2*m_FFTLength) - 2*col - 2 ];
@@ -340,10 +344,11 @@
     {
 	const unsigned row = cqbin[i];
 	const unsigned col = fftbin[i];
+        if (col == 0) continue;
 	const double & r1  = real[i];
 	const double & i1  = imag[i];
-	const double & r2  = FFTRe[ m_FFTLength - col - 1 ];
-	const double & i2  = FFTIm[ m_FFTLength - col - 1 ];
+	const double & r2  = FFTRe[ m_FFTLength - col ];
+	const double & i2  = FFTIm[ m_FFTLength - col ];
 	// add the multiplication
 	CQRe[ row ] += (r1*r2 - i1*i2);
 	CQIm[ row ] += (r1*i2 + i1*r2);