150 lines
3.3 KiB
C++
150 lines
3.3 KiB
C++
/* -*- 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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