 Math::GSL::Sys(3) Misc Math Functions

## SYNOPSIS

use Math::GSL::Sys qw/:all/;

## DESCRIPTION

This module contains various useful math functions that are not usually provided by standard libraries.
• "gsl_log1p($x)" This function computes the value of \log(1+$x) in a way that is accurate for small $x. It provides an alternative to the BSD math function log1p(x). • "gsl_expm1($x)"

This function computes the value of \exp($x)-1 in a way that is accurate for small$x. It provides an alternative to the BSD math function expm1(x).

• "gsl_hypot($x,$y)"

This function computes the value of \sqrt{$x^2 +$y^2} in a way that avoids overflow. It provides an alternative to the BSD math function hypot($x,$y).

• "gsl_hypot3($x,$y, $z)" This function computes the value of \sqrt{$x^2 + $y^2 +$z^2} in a way that avoids overflow.

• "gsl_acosh($x)" This function computes the value of \arccosh($x). It provides an alternative to the standard math function acosh($x). • "gsl_asinh($x)"

This function computes the value of \arcsinh($x). It provides an alternative to the standard math function asinh($x).

• "gsl_atanh($x)" This function computes the value of \arctanh($x). It provides an alternative to the standard math function atanh($x). • "gsl_isnan($x)"

This function returns 1 if $x is not-a-number. • "gsl_isinf($x)"

This function returns +1 if $x is positive infinity, -1 if$x is negative infinity and 0 otherwise.

• "gsl_finite($x)" This function returns 1 if$x is a real number, and 0 if it is infinite or not-a-number.

• "gsl_posinf "
• "gsl_neginf "
• "gsl_fdiv "
• "gsl_coerce_double "
• "gsl_coerce_float "
• "gsl_coerce_long_double "
• "gsl_ldexp($x,$e)"

This function computes the value of $x * 2**$e. It provides an alternative to the standard math function ldexp($x,$e).

• "gsl_frexp($x)" This function splits the number$x into its normalized fraction f and exponent e, such that $x = f * 2^e and 0.5 <= f < 1. The function returns f and then the exponent in e. If$x is zero, both f and e are set to zero. This function provides an alternative to the standard math function frexp(x, e).

• "gsl_fcmp($x,$y, $epsilon)" This function determines whether$x and $y are approximately equal to a relative accuracy$epsilon. The relative accuracy is measured using an interval of size 2 \delta, where \delta = 2^k \epsilon and k is the maximum base-2 exponent of $x and$y as computed by the function frexp. If $x and$y lie within this interval, they are considered approximately equal and the function returns 0. Otherwise if $x <$y, the function returns -1, or if $x >$y, the function returns +1. Note that $x and$y are compared to relative accuracy, so this function is not suitable for testing whether a value is approximately zero. The implementation is based on the package fcmp by T.C. Belding.

For more information on the functions, we refer you to the GSL offcial documentation: <http://www.gnu.org/software/gsl/manual/html_node/>

## AUTHORS

Jonathan Duke'' Leto <[email protected]> and Thierry Moisan <[email protected]>

Copyright (C) 2008-2011 Jonathan Duke'' Leto and Thierry Moisan