cannam@0: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
cannam@0: 
cannam@0: /*
cannam@0:     QM DSP Library
cannam@0: 
cannam@0:     Centre for Digital Music, Queen Mary, University of London.
Chris@84:     This file 2005-2006 Christian Landone.
Chris@84: 
Chris@84:     This program is free software; you can redistribute it and/or
Chris@84:     modify it under the terms of the GNU General Public License as
Chris@84:     published by the Free Software Foundation; either version 2 of the
Chris@84:     License, or (at your option) any later version.  See the file
Chris@84:     COPYING included with this distribution for more information.
cannam@0: */
cannam@0: 
cannam@0: #ifndef MATHUTILITIES_H
cannam@0: #define MATHUTILITIES_H
cannam@0: 
cannam@0: #include <vector>
cannam@0: 
cannam@79: #include "nan-inf.h"
cannam@79: 
Chris@152: /**
Chris@152:  * Static helper functions for simple mathematical calculations.
Chris@152:  */
cannam@0: class MathUtilities  
cannam@0: {
cannam@0: public:	
Chris@152:     /**
Chris@152:      * Round x to the nearest integer.
Chris@152:      */
cannam@0:     static double round( double x );
cannam@34: 
Chris@152:     /**
Chris@152:      * Return through min and max pointers the highest and lowest
Chris@152:      * values in the given array of the given length.
Chris@152:      */
cannam@0:     static void	  getFrameMinMax( const double* data, unsigned int len,  double* min, double* max );
cannam@34: 
Chris@152:     /**
Chris@152:      * Return the mean of the given array of the given length.
Chris@152:      */
cannam@0:     static double mean( const double* src, unsigned int len );
Chris@152: 
Chris@152:     /**
Chris@152:      * Return the mean of the subset of the given vector identified by
Chris@152:      * start and count.
Chris@152:      */
cannam@54:     static double mean( const std::vector<double> &data,
cannam@54:                         unsigned int start, unsigned int count );
Chris@152:     
Chris@152:     /**
Chris@152:      * Return the sum of the values in the given array of the given
Chris@152:      * length.
Chris@152:      */
cannam@0:     static double sum( const double* src, unsigned int len );
Chris@152: 
Chris@152:     /**
Chris@152:      * Return the median of the values in the given array of the given
Chris@152:      * length. If the array is even in length, the returned value will
Chris@152:      * be half-way between the two values adjacent to median.
Chris@152:      */
cannam@34:     static double median( const double* src, unsigned int len );
cannam@34: 
Chris@152:     /**
Chris@152:      * The principle argument function. Map the phase angle ang into
Chris@152:      * the range [-pi,pi).
Chris@152:      */
cannam@0:     static double princarg( double ang );
Chris@152: 
Chris@152:     /**
Chris@152:      * Floating-point division modulus: return x % y.
Chris@152:      */
cannam@0:     static double mod( double x, double y);
cannam@34: 
cannam@0:     static void	  getAlphaNorm(const double *data, unsigned int len, unsigned int alpha, double* ANorm);
cannam@0:     static double getAlphaNorm(const std::vector <double> &data, unsigned int alpha );
cannam@34: 
cannam@7:     static void   circShift( double* data, int length, int shift);
cannam@34: 
cannam@54:     static int	  getMax( double* data, unsigned int length, double* max = 0 );
cannam@54:     static int	  getMax( const std::vector<double> &data, double* max = 0 );
cannam@7:     static int    compareInt(const void * a, const void * b);
cannam@34: 
cannam@34:     enum NormaliseType {
cannam@34:         NormaliseNone,
cannam@34:         NormaliseUnitSum,
cannam@34:         NormaliseUnitMax
cannam@34:     };
cannam@34: 
Chris@123:     static void normalise(double *data, int length,
Chris@123:                           NormaliseType n = NormaliseUnitMax);
cannam@34: 
Chris@123:     static void normalise(std::vector<double> &data,
Chris@123:                           NormaliseType n = NormaliseUnitMax);
cannam@54: 
Chris@152:     /**
Chris@152:      * Threshold the input/output vector data against a moving-mean
Chris@152:      * average filter.
Chris@152:      */
cannam@54:     static void adaptiveThreshold(std::vector<double> &data);
cannam@55: 
Chris@152:     /** 
Chris@152:      * Return true if x is 2^n for some integer n >= 0.
Chris@152:      */
cannam@55:     static bool isPowerOfTwo(int x);
Chris@123: 
Chris@152:     /**
Chris@152:      * Return the next higher integer power of two from x, e.g. 1300
Chris@152:      * -> 2048, 2048 -> 2048.
Chris@152:      */
Chris@152:     static int nextPowerOfTwo(int x);
Chris@152: 
Chris@152:     /**
Chris@152:      * Return the next lower integer power of two from x, e.g. 1300 ->
Chris@152:      * 1024, 2048 -> 2048.
Chris@152:      */
Chris@152:     static int previousPowerOfTwo(int x);
Chris@152: 
Chris@152:     /**
Chris@152:      * Return the nearest integer power of two to x, e.g. 1300 -> 1024,
Chris@152:      * 12 -> 16 (not 8; if two are equidistant, the higher is returned).
Chris@152:      */
Chris@152:     static int nearestPowerOfTwo(int x);
Chris@152: 
Chris@152:     /**
Chris@152:      * Return x!
Chris@152:      */
Chris@135:     static double factorial(int x); // returns double in case it is large
Chris@125: 
Chris@152:     /**
Chris@152:      * Return the greatest common divisor of natural numbers a and b.
Chris@152:      */
Chris@125:     static int gcd(int a, int b);
cannam@0: };
cannam@0: 
cannam@0: #endif