diff options
Diffstat (limited to 'libs/qm-dsp/maths/MathUtilities.h')
-rw-r--r-- | libs/qm-dsp/maths/MathUtilities.h | 88 |
1 files changed, 78 insertions, 10 deletions
diff --git a/libs/qm-dsp/maths/MathUtilities.h b/libs/qm-dsp/maths/MathUtilities.h index 85774756d4..fac710af9a 100644 --- a/libs/qm-dsp/maths/MathUtilities.h +++ b/libs/qm-dsp/maths/MathUtilities.h @@ -20,20 +20,57 @@ #include "nan-inf.h" -class MathUtilities +/** + * Static helper functions for simple mathematical calculations. + */ +class MathUtilities { -public: +public: + /** + * Round x to the nearest integer. + */ static double round( double x ); + /** + * Return through min and max pointers the highest and lowest + * values in the given array of the given length. + */ static void getFrameMinMax( const double* data, unsigned int len, double* min, double* max ); + /** + * Return the mean of the given array of the given length. + */ static double mean( const double* src, unsigned int len ); + + /** + * Return the mean of the subset of the given vector identified by + * start and count. + */ static double mean( const std::vector<double> &data, unsigned int start, unsigned int count ); + + /** + * Return the sum of the values in the given array of the given + * length. + */ static double sum( const double* src, unsigned int len ); + + /** + * Return the median of the values in the given array of the given + * length. If the array is even in length, the returned value will + * be half-way between the two values adjacent to median. + */ static double median( const double* src, unsigned int len ); + /** + * The principle argument function. Map the phase angle ang into + * the range [-pi,pi). + */ static double princarg( double ang ); + + /** + * Floating-point division modulus: return x % y. + */ static double mod( double x, double y); static void getAlphaNorm(const double *data, unsigned int len, unsigned int alpha, double* ANorm); @@ -51,19 +88,50 @@ public: NormaliseUnitMax }; - static void normalise(double *data, int length, - NormaliseType n = NormaliseUnitMax); + static void normalise(double *data, int length, + NormaliseType n = NormaliseUnitMax); - static void normalise(std::vector<double> &data, - NormaliseType n = NormaliseUnitMax); + static void normalise(std::vector<double> &data, + NormaliseType n = NormaliseUnitMax); - // moving mean threshholding: + /** + * Threshold the input/output vector data against a moving-mean + * average filter. + */ static void adaptiveThreshold(std::vector<double> &data); + /** + * Return true if x is 2^n for some integer n >= 0. + */ static bool isPowerOfTwo(int x); - static int nextPowerOfTwo(int x); // e.g. 1300 -> 2048, 2048 -> 2048 - static int previousPowerOfTwo(int x); // e.g. 1300 -> 1024, 2048 -> 2048 - static int nearestPowerOfTwo(int x); // e.g. 1300 -> 1024, 1700 -> 2048 + + /** + * Return the next higher integer power of two from x, e.g. 1300 + * -> 2048, 2048 -> 2048. + */ + static int nextPowerOfTwo(int x); + + /** + * Return the next lower integer power of two from x, e.g. 1300 -> + * 1024, 2048 -> 2048. + */ + static int previousPowerOfTwo(int x); + + /** + * Return the nearest integer power of two to x, e.g. 1300 -> 1024, + * 12 -> 16 (not 8; if two are equidistant, the higher is returned). + */ + static int nearestPowerOfTwo(int x); + + /** + * Return x! + */ + static double factorial(int x); // returns double in case it is large + + /** + * Return the greatest common divisor of natural numbers a and b. + */ + static int gcd(int a, int b); }; #endif |