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Diffstat (limited to 'src/3rdparty/2geom/include/2geom/math-utils.h')
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diff --git a/src/3rdparty/2geom/include/2geom/math-utils.h b/src/3rdparty/2geom/include/2geom/math-utils.h new file mode 100644 index 0000000..ee923f5 --- /dev/null +++ b/src/3rdparty/2geom/include/2geom/math-utils.h @@ -0,0 +1,110 @@ +/** + * \file + * \brief Low level math functions and compatibility wrappers + *//* + * Authors: + * Johan Engelen <goejendaagh@zonnet.nl> + * Michael G. Sloan <mgsloan@gmail.com> + * Krzysztof Kosiński <tweenk.pl@gmail.com> + * Copyright 2006-2009 Authors + * + * This library is free software; you can redistribute it and/or + * modify it either under the terms of the GNU Lesser General Public + * License version 2.1 as published by the Free Software Foundation + * (the "LGPL") or, at your option, under the terms of the Mozilla + * Public License Version 1.1 (the "MPL"). If you do not alter this + * notice, a recipient may use your version of this file under either + * the MPL or the LGPL. + * + * You should have received a copy of the LGPL along with this library + * in the file COPYING-LGPL-2.1; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * You should have received a copy of the MPL along with this library + * in the file COPYING-MPL-1.1 + * + * The contents of this file are subject to the Mozilla Public License + * Version 1.1 (the "License"); you may not use this file except in + * compliance with the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY + * OF ANY KIND, either express or implied. See the LGPL or the MPL for + * the specific language governing rights and limitations. + * + */ + +#ifndef LIB2GEOM_SEEN_MATH_UTILS_H +#define LIB2GEOM_SEEN_MATH_UTILS_H + +#include <math.h> // sincos is usually only available in math.h +#include <cmath> +#include <utility> // for std::pair +#include <boost/math/special_functions/fpclassify.hpp> + +namespace Geom { + +/** @brief Sign function - indicates the sign of a numeric type. + * Mathsy people will know this is basically the derivative of abs, except for the fact + * that it is defined on 0. + * @return -1 when x is negative, 1 when positive, and 0 if equal to 0. */ +template <class T> inline int sgn(const T& x) { + return (x < 0 ? -1 : (x > 0 ? 1 : 0) ); +// can we 'optimize' this with: +// return ( (T(0) < x) - (x < T(0)) ); +} + +template <class T> inline T sqr(const T& x) {return x * x;} +template <class T> inline T cube(const T& x) {return x * x * x;} + +/** Between function - returns true if a number x is within a range: (min < x) && (max > x). + * The values delimiting the range and the number must have the same type. + */ +template <class T> inline const T& between (const T& min, const T& max, const T& x) + { return (min < x) && (max > x); } + +/** @brief Returns @a x rounded to the nearest multiple of \f$10^{p}\f$. + + Implemented in terms of round, i.e. we make no guarantees as to what happens if x is + half way between two rounded numbers. + + Note: places is the number of decimal places without using scientific (e) notation, not the + number of significant figures. This function may not be suitable for values of x whose + magnitude is so far from 1 that one would want to use scientific (e) notation. + + places may be negative: e.g. places = -2 means rounding to a multiple of .01 +**/ +inline double decimal_round(double x, int p) { + //TODO: possibly implement with modulus instead? + double const multiplier = ::pow(10.0, p); + return ::round( x * multiplier ) / multiplier; +} + +/** @brief Simultaneously compute a sine and a cosine of the same angle. + * This function can be up to 2 times faster than separate computation, depending + * on the platform. It uses the standard library function sincos() if available. + * @param angle Angle + * @param sin_ Variable that will store the sine + * @param cos_ Variable that will store the cosine */ +inline void sincos(double angle, double &sin_, double &cos_) { +#ifdef HAVE_SINCOS + ::sincos(angle, &sin_, &cos_); +#else + sin_ = ::sin(angle); + cos_ = ::cos(angle); +#endif +} + +} // end namespace Geom + +#endif // LIB2GEOM_SEEN_MATH_UTILS_H + +/* + Local Variables: + mode:c++ + c-file-style:"stroustrup" + c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +)) + indent-tabs-mode:nil + fill-column:99 + End: +*/ +// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 : |