MathUtilities.h

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/* -*- 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.
*/

#ifndef MATHUTILITIES_H
#define MATHUTILITIES_H

#include <vector>

#include "nan-inf.h"

class MathUtilities  
{
public: 
    static double round( double x );

    static void getFrameMinMax( const double* data, int len,
                                double* min, double* max );

    static double mean( const double* src, int len );

    static double mean( const std::vector<double> &data,
                        int start, int count );
    
    static double sum( const double* src, int len );

    static double median( const double* src, int len );

    static double princarg( double ang );

    static double mod( double x, double y);

    static void getAlphaNorm(const double *data, int len, int alpha, double* ANorm);

    static double getAlphaNorm(const std::vector <double> &data, int alpha );

    enum NormaliseType {
        NormaliseNone,
        NormaliseUnitSum,
        NormaliseUnitMax
    };

    static void normalise(double *data, int length,
                          NormaliseType n = NormaliseUnitMax);

    static void normalise(std::vector<double> &data,
                          NormaliseType n = NormaliseUnitMax);

    static double getLpNorm(const std::vector<double> &data,
                            int p);

    static std::vector<double> normaliseLp(const std::vector<double> &data,
                                           int p,
                                           double threshold = 1e-6);
    
    static void adaptiveThreshold(std::vector<double> &data);

    static void circShift( double* data, int length, int shift);

    static int getMax( double* data, int length, double* max = 0 );
    static int getMax( const std::vector<double> &data, double* max = 0 );
    static int compareInt(const void * a, const void * b);

    static bool isPowerOfTwo(int x);

    static int nextPowerOfTwo(int x);

    static int previousPowerOfTwo(int x);

    static int nearestPowerOfTwo(int x);

    static double factorial(int x); // returns double in case it is large

    static int gcd(int a, int b);
};

#endif