annotate dsp/chromagram/ConstantQ.cpp @ 487:5998ee1042d3

Use M_PI

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
/*
    QM DSP Library

    Centre for Digital Music, Queen Mary, University of London.
    This file 2005-2006 Christian Landone.

    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#include "ConstantQ.h"
#include "dsp/transforms/FFT.h"

#include <iostream>

//---------------------------------------------------------------------------
// nextpow2 returns the smallest integer n such that 2^n >= x.
static double nextpow2(double x) {
    double y = ceil(log(x)/log(2.0));
    return(y);
}

static double squaredModule(const double & xx, const double & yy) {
    return xx*xx + yy*yy;
}

//----------------------------------------------------------------------------

ConstantQ::ConstantQ( CQConfig Config ) :
    m_sparseKernel(0)
{
    initialise( Config );
}

ConstantQ::~ConstantQ()
{
    deInitialise();
}

//----------------------------------------------------------------------------
void ConstantQ::sparsekernel()
{
//    std::cerr << "ConstantQ: initialising sparse kernel, uK = " << m_uK << ", FFTLength = " << m_FFTLength << "...";

    SparseKernel *sk = new SparseKernel();

    //generates spectral kernel matrix (upside down?)
    // initialise temporal kernel with zeros, twice length to deal w. complex numbers

    double* hammingWindowRe = new double [ m_FFTLength ];
    double* hammingWindowIm = new double [ m_FFTLength ];
    double* transfHammingWindowRe = new double [ m_FFTLength ];
    double* transfHammingWindowIm = new double [ m_FFTLength ];

    for (unsigned u=0; u < m_FFTLength; u++) {
        hammingWindowRe[u] = 0;
        hammingWindowIm[u] = 0;
    }

    // Here, fftleng*2 is a guess of the number of sparse cells in the matrix
    // The matrix K x fftlength but the non-zero cells are an antialiased
    // square root function. So mostly is a line, with some grey point.
    sk->is.reserve( m_FFTLength*2 );
    sk->js.reserve( m_FFTLength*2 );
    sk->real.reserve( m_FFTLength*2 );
    sk->imag.reserve( m_FFTLength*2 );
        
    // for each bin value K, calculate temporal kernel, take its fft to
    //calculate the spectral kernel then threshold it to make it sparse and 
    //add it to the sparse kernels matrix
    double squareThreshold = m_CQThresh * m_CQThresh;

    FFT m_FFT(m_FFTLength);
        
    for (unsigned k = m_uK; k--; ) {
        for (unsigned u=0; u < m_FFTLength; u++) {
            hammingWindowRe[u] = 0;
            hammingWindowIm[u] = 0;
        }
        
        // 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++) {
            const double angle = 2*M_PI*m_dQ*i/hammingLength;
            const double real = cos(angle);
            const double imag = sin(angle);
            const double absol = hamming(hammingLength, i)/hammingLength;
            hammingWindowRe[ origin + i ] = absol*real;
            hammingWindowIm[ origin + i ] = absol*imag;
        }

        for (unsigned i = 0; i < m_FFTLength/2; ++i) {
            double temp = hammingWindowRe[i];
            hammingWindowRe[i] = hammingWindowRe[i + m_FFTLength/2];
            hammingWindowRe[i + m_FFTLength/2] = temp;
            temp = hammingWindowIm[i];
            hammingWindowIm[i] = hammingWindowIm[i + m_FFTLength/2];
            hammingWindowIm[i + m_FFTLength/2] = temp;
        }
    
        //do fft of hammingWindow
        m_FFT.process( 0, hammingWindowRe, hammingWindowIm, transfHammingWindowRe, transfHammingWindowIm );
                
        for (unsigned j=0; j<( m_FFTLength ); j++) {
            // perform thresholding
            const double squaredBin = squaredModule( transfHammingWindowRe[ j ], transfHammingWindowIm[ j ]);
            if (squaredBin <= squareThreshold) continue;
                
            // Insert non-zero position indexes
            sk->is.push_back(j);
            sk->js.push_back(k);

            // take conjugate, normalise and add to array sparkernel
            sk->real.push_back( transfHammingWindowRe[ j ]/m_FFTLength);
            sk->imag.push_back(-transfHammingWindowIm[ j ]/m_FFTLength);
        }
    }

    delete [] hammingWindowRe;
    delete [] hammingWindowIm;
    delete [] transfHammingWindowRe;
    delete [] transfHammingWindowIm;

//    std::cerr << "done\n -> is: " << sk->is.size() << ", js: " << sk->js.size() << ", reals: " << sk->real.size() << ", imags: " << sk->imag.size() << std::endl;
    
    m_sparseKernel = sk;
    return;
}

//-----------------------------------------------------------------------------
double* ConstantQ::process( const double* fftdata )
{
    if (!m_sparseKernel) {
        std::cerr << "ERROR: ConstantQ::process: Sparse kernel has not been initialised" << std::endl;
        return m_CQdata;
    }

    SparseKernel *sk = m_sparseKernel;

    for (unsigned row=0; row<2*m_uK; row++) {
        m_CQdata[ row ] = 0;
        m_CQdata[ row+1 ] = 0;
    }
    const unsigned *fftbin = &(sk->is[0]);
    const unsigned *cqbin  = &(sk->js[0]);
    const double   *real   = &(sk->real[0]);
    const double   *imag   = &(sk->imag[0]);
    const unsigned int sparseCells = sk->real.size();
        
    for (unsigned i = 0; i<sparseCells; i++) {
        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 ];
        const double & i2  = fftdata[ (2*m_FFTLength) - 2*col - 2 + 1 ];
        // add the multiplication
        m_CQdata[ 2*row  ] += (r1*r2 - i1*i2);
        m_CQdata[ 2*row+1] += (r1*i2 + i1*r2);
    }

    return m_CQdata;
}


void ConstantQ::initialise( CQConfig Config )
{
    m_FS = Config.FS;
    m_FMin = Config.min;                // min freq
    m_FMax = Config.max;                // max freq
    m_BPO = Config.BPO;         // bins per octave
    m_CQThresh = Config.CQThresh;// ConstantQ threshold for kernel generation

    m_dQ = 1/(pow(2,(1/(double)m_BPO))-1);      // Work out Q value for Filter bank
    m_uK = (unsigned int) ceil(m_BPO * log(m_FMax/m_FMin)/log(2.0));    // No. of constant Q bins

//    std::cerr << "ConstantQ::initialise: rate = " << m_FS << ", fmin = " << m_FMin << ", fmax = " << m_FMax << ", bpo = " << m_BPO << ", K = " << m_uK << ", Q = " << m_dQ << std::endl;

    // work out length of fft required for this constant Q Filter bank
    m_FFTLength = (int) pow(2, nextpow2(ceil( m_dQ*m_FS/m_FMin )));

    m_hop = m_FFTLength/8;

//    std::cerr << "ConstantQ::initialise: -> fft length = " << m_FFTLength << ", hop = " << m_hop << std::endl;

    // allocate memory for cqdata
    m_CQdata = new double [2*m_uK];
}

void ConstantQ::deInitialise()
{
    delete [] m_CQdata;
    delete m_sparseKernel;
}

void ConstantQ::process(const double *FFTRe, const double* FFTIm,
                        double *CQRe, double *CQIm)
{
    if (!m_sparseKernel) {
        std::cerr << "ERROR: ConstantQ::process: Sparse kernel has not been initialised" << std::endl;
        return;
    }

    SparseKernel *sk = m_sparseKernel;

    for (unsigned row=0; row<m_uK; row++) {
        CQRe[ row ] = 0;
        CQIm[ row ] = 0;
    }

    const unsigned *fftbin = &(sk->is[0]);
    const unsigned *cqbin  = &(sk->js[0]);
    const double   *real   = &(sk->real[0]);
    const double   *imag   = &(sk->imag[0]);
    const unsigned int sparseCells = sk->real.size();
        
    for (unsigned i = 0; i<sparseCells; i++) {
        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 ];
        const double & i2  = FFTIm[ m_FFTLength - col ];
        // add the multiplication
        CQRe[ row ] += (r1*r2 - i1*i2);
        CQIm[ row ] += (r1*i2 + i1*r2);
    }
}