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.