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149 lines
3.3 KiB
149 lines
3.3 KiB
/* -*- mode: C++ ; c-file-style: "stroustrup" -*- ***************************** |
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* Qwt Widget Library |
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* Copyright (C) 1997 Josef Wilgen |
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* Copyright (C) 2002 Uwe Rathmann |
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* |
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* This library is free software; you can redistribute it and/or |
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* modify it under the terms of the Qwt License, Version 1.0 |
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*****************************************************************************/ |
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#ifndef QWT_MATH_H |
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#define QWT_MATH_H |
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#include "qwt_global.h" |
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#if defined(_MSC_VER) |
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/* |
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Microsoft says: |
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Define _USE_MATH_DEFINES before including math.h to expose these macro |
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definitions for common math constants. These are placed under an #ifdef |
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since these commonly-defined names are not part of the C/C++ standards. |
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*/ |
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#define _USE_MATH_DEFINES 1 |
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#endif |
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#include <qmath.h> |
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#include "qwt_global.h" |
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#ifndef M_PI_2 |
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// For Qt <= 4.8.4 M_PI_2 is not known by MinGW-w64 |
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// when compiling with -std=c++11 |
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#define M_PI_2 (1.57079632679489661923) |
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#endif |
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#ifndef LOG_MIN |
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//! Minimum value for logarithmic scales |
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#define LOG_MIN 1.0e-100 |
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#endif |
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#ifndef LOG_MAX |
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//! Maximum value for logarithmic scales |
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#define LOG_MAX 1.0e100 |
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#endif |
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QWT_EXPORT double qwtGetMin( const double *array, int size ); |
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QWT_EXPORT double qwtGetMax( const double *array, int size ); |
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QWT_EXPORT double qwtNormalizeRadians( double radians ); |
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QWT_EXPORT double qwtNormalizeDegrees( double degrees ); |
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/*! |
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\brief Compare 2 values, relative to an interval |
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Values are "equal", when : |
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\f$\cdot value2 - value1 <= abs(intervalSize * 10e^{-6})\f$ |
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\param value1 First value to compare |
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\param value2 Second value to compare |
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\param intervalSize interval size |
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\return 0: if equal, -1: if value2 > value1, 1: if value1 > value2 |
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*/ |
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inline int qwtFuzzyCompare( double value1, double value2, double intervalSize ) |
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{ |
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const double eps = qAbs( 1.0e-6 * intervalSize ); |
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if ( value2 - value1 > eps ) |
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return -1; |
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if ( value1 - value2 > eps ) |
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return 1; |
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return 0; |
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} |
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inline bool qwtFuzzyGreaterOrEqual( double d1, double d2 ) |
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{ |
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return ( d1 >= d2 ) || qFuzzyCompare( d1, d2 ); |
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} |
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inline bool qwtFuzzyLessOrEqual( double d1, double d2 ) |
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{ |
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return ( d1 <= d2 ) || qFuzzyCompare( d1, d2 ); |
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} |
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//! Return the sign |
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inline int qwtSign( double x ) |
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{ |
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if ( x > 0.0 ) |
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return 1; |
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else if ( x < 0.0 ) |
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return ( -1 ); |
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else |
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return 0; |
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} |
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//! Return the square of a number |
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inline double qwtSqr( double x ) |
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{ |
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return x * x; |
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} |
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//! Approximation of arc tangent ( error below 0,005 radians ) |
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inline double qwtFastAtan( double x ) |
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{ |
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if ( x < -1.0 ) |
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return -M_PI_2 - x / ( x * x + 0.28 ); |
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if ( x > 1.0 ) |
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return M_PI_2 - x / ( x * x + 0.28 ); |
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return x / ( 1.0 + x * x * 0.28 ); |
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} |
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//! Approximation of arc tangent ( error below 0,005 radians ) |
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inline double qwtFastAtan2( double y, double x ) |
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{ |
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if ( x > 0 ) |
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return qwtFastAtan( y / x ); |
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if ( x < 0 ) |
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{ |
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const double d = qwtFastAtan( y / x ); |
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return ( y >= 0 ) ? d + M_PI : d - M_PI; |
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} |
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if ( y < 0.0 ) |
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return -M_PI_2; |
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if ( y > 0.0 ) |
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return M_PI_2; |
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return 0.0; |
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} |
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// Translate degrees into radians |
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inline double qwtRadians( double degrees ) |
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{ |
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return degrees * M_PI / 180.0; |
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} |
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// Translate radians into degrees |
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inline double qwtDegrees( double degrees ) |
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{ |
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return degrees * 180.0 / M_PI; |
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} |
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#endif
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