# leto/math--gsl

Clean up Sys POD

 @@ -37,36 +37,66 @@ __END__ =head1 NAME -Math::GSL::Sys - +Math::GSL::Sys - Misc Math Functions =head1 SYNOPSIS -use Math::GSL::Sys qw /:all/; + use Math::GSL::Sys qw/:all/; =head1 DESCRIPTION -Here is a list of all the functions in this module : +This module contains various useful math functions that are not usually +provided by standard libraries. =over -=item * C - 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). -=item * C - 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). +=item * C -=item * C - 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). +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). -=item * C - This function computes the value of \sqrt{$x^2 +$y^2 + $z^2} in a way that avoids overflow. +=item * C -=item * C - This function computes the value of \arccosh($x). It provides an alternative to the standard math function acosh($x). +This function computes the value of \exp($x)-1 in a way that is accurate for +small $x. It provides an alternative to the BSD math function expm1(x). -=item * C - This function computes the value of \arcsinh($x). It provides an alternative to the standard math function asinh($x). +=item * C -=item * C - This function computes the value of \arctanh($x). It provides an alternative to the standard math function atanh($x). +This function computes the value of \sqrt{$x^2 + $y^2} in a way that avoids +overflow. It provides an alternative to the BSD math function hypot($x,$y). -=item * C - This function returns 1 if$x is not-a-number. +=item * C -=item * C - This function returns +1 if $x is positive infinity, -1 if$x is negative infinity and 0 otherwise. +This function computes the value of \sqrt{$x^2 +$y^2 + $z^2} in a way that +avoids overflow. -=item * C - This function returns 1 if$x is a real number, and 0 if it is infinite or not-a-number. +=item * C + +This function computes the value of \arccosh($x). It provides an alternative to +the standard math function acosh($x). + +=item * C + +This function computes the value of \arcsinh($x). It provides an alternative to +the standard math function asinh($x). + +=item * C + +This function computes the value of \arctanh($x). It provides an alternative to +the standard math function atanh($x). + +=item * C + +This function returns 1 if $x is not-a-number. + +=item * C + +This function returns +1 if$x is positive infinity, -1 if $x is negative +infinity and 0 otherwise. + +=item * C + +This function returns 1 if$x is a real number, and 0 if it is infinite or not-a-number. =item * C @@ -80,20 +110,35 @@ Here is a list of all the functions in this module : =item * C -=item * C - This function computes the value of $x * 2**$e. It provides an alternative to the standard math function ldexp($x,$e). +=item * C + +This function computes the value of $x * 2**$e. It provides an alternative to +the standard math function ldexp($x,$e). + +=item * C -=item * C - 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 $x is zero, both f and e are set to zero. This function provides an alternative to the standard math function frexp(x, e). +This function splits the number$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). -=item * C - 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 $y are compared to relative accuracy, so this function is not suitable for testing whether a value is approximately zero. The implementation is based on the package fcmp by T.C. Belding. +=item * C + +This function determines whether$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. =back For more informations on the functions, we refer you to the GSL offcial documentation: L - Tip : search on google: site:http://www.gnu.org/software/gsl/manual/html_node/ name_of_the_function_you_want - - =head1 AUTHORS Jonathan "Duke" Leto and Thierry Moisan @@ -108,4 +153,3 @@ under the same terms as Perl itself. =cut %} -