simple.hpp

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/*****************************************************************************
** Ifdefs
*****************************************************************************/

#ifndef ECL_CORE_MATH_SIMPLE_HPP_
#define ECL_CORE_MATH_SIMPLE_HPP_

/*****************************************************************************
** Includes
*****************************************************************************/

#include <cmath>

/*****************************************************************************
** Namespaces
*****************************************************************************/

namespace ecl {

/*****************************************************************************
** Functions
*****************************************************************************/
template <typename Scalar>
inline int sign(const Scalar &x) {
        // ToDo: should probably check some numeric traits here
        // Is this faster? (v > 0) - (v < 0);
        // http://stackoverflow.com/questions/1903954/is-there-a-standard-sign-function-signum-sgn-in-c-c
        if ( x > 0 ) {
                return 1;
        } else if ( x < 0 ) {
                return -1;
        } else {
                return 0;
        }
}

template <typename Scalar>
inline int psign(const Scalar &x) {
        // ToDo: should probably check some numeric traits here
        if ( x >= 0 ) {
                return 1;
        } else {
                return -1;
        }
}

template <typename Scalar>
inline int nsign(const Scalar &x) {
        // ToDo: should probably check some numeric traits here
        if ( x > 0 ) {
                return 1;
        } else {
                return -1;
        }
}

template <typename Scalar>
inline Scalar cube_root(const Scalar &x) {
        // ToDo: should probably check some numeric traits here
        return psign(x)*pow(fabs(x),1.0/3.0);
}


} // namespace ecl

#endif /* ECL_CORE_MATH_SIMPLE_HPP_ */