NAME¶
PDL::GSL::MROOT - PDL interface to multidimensional root-finding routines in GSL
DESCRIPTION¶
This is an interface to the multidimensional root-finding package present in the
GNU Scientific Library.
At the moment there is a single function
gslmroot_fsolver which provides
an interface to the algorithms in the GSL library that do not use derivatives.
SYNOPSIS¶
use PDL;
use PDL::GSL::MROOT;
my $init = pdl (-10.00, -5.0);
my $epsabs = 1e-7;
$res = gslmroot_fsolver($init, \&rosenbrock,
{Method => 0, EpsAbs => $epsabs});
sub rosenbrock{
my ($x) = @_;
my $a = 1;
my $b = 10;
my $y = zeroes($x);
my $y0 = $y->slice(0);
$y0 .= $a * (1 - $x->slice(0));
my $y1 = $y->slice(1);
$y1 .= $b * ($x->slice(1) - $x->slice(0)**2);
return $y;
}
FUNCTIONS¶
gslmroot_fsolver -- Multidimensional root finder without using derivatives¶
This function provides an interface to the multidimensional root finding
algorithms in the GSL library. It takes a minimum of two argumennts: a piddle
$init with an initial guess for the roots of the system and a reference to a
function. The latter function must return a piddle whose i-th element is the
i-th equation evaluated at the vector x (a piddle which is the sole input to
this function). See the example in the Synopsis above for an illustration. The
function returns a piddle with the roots for the system of equations.
Two optional arguments can be specified as shown below. One is
Method,
which can take the values 0,1,2,3. They correspond to the 'hybrids', 'hybrid',
'dnewton' and 'broyden' algorithms respectively (see GSL documentation for
details). The other optional argument is
Epsabs, which sets the
absolute accuracy to which the roots of the system of equations are required.
The default value for Method is 0 ('hybrids' algorithm) and the default for
Epsabs is 1e-3.
Usage:
$res = gslmroot_fsolver($init, $function_ref,
[{Method => $method, Epsabs => $epsabs}]);
SEE ALSO¶
PDL
The GSL documentation is online at
http://www.gnu.org/software/gsl/manual/
AUTHOR¶
This file copyright (C) 2006 Andres Jordan <ajordan@eso.org> and Simon
Casassus <simon@das.uchile.cl> All rights reserved. There is no
warranty. You are allowed to redistribute this software/documentation under
certain conditions. For details, see the file COPYING in the PDL distribution.
If this file is separated from the PDL distribution, the copyright notice
should be included in the file.
FUNCTIONS¶
fsolver_meat¶
Signature: (double xfree(n); double epsabs(); int method(); SV* funcion1)
info not available
fsolver_meat does not process bad values. It will set the bad-value flag of all
output piddles if the flag is set for any of the input piddles.