pdl::gsl::mroot(3) [suse man page]

MROOT(3)						User Contributed Perl Documentation						  MROOT(3)

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);
	    $y->slice(0) .=  $a * (1 - $x->slice(0));
	    $y->slice(1) .=  $b * ($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://sources.redhat.com/gsl/ref/gsl-ref_toc.html

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.

perl v5.12.1							    2010-07-05								  MROOT(3)

DIFF(3) 						User Contributed Perl Documentation						   DIFF(3)

NAME

       PDL::GSL::DIFF - PDL interface to numerical differentiation routines in GSL

DESCRIPTION

       This is an interface to the numerical differentiation package present in the GNU Scientific Library.

SYNOPSIS

	  use PDL;
	  use PDL::GSL::DIFF;

	  my $x0 = 3.3;

	  my @res = gsldiff(&myfunction,$x0);
	  # same as above:
	  @res = gsldiff(&myfunction,$x0,{Method => 'central'});

	  # use only values greater than $x0 to get the derivative
	  @res =  gsldiff(&myfunction,$x0,{Method => 'forward'});

	  # use only values smaller than $x0 to get the derivative
	  @res = gsldiff(&myfunction,$x0,{Method => 'backward'});

	  sub myfunction{
	    my ($x) = @_;
	    return $x**2;
	  }

FUNCTIONS

   gsldiff()
       This functions serves as an interface to the three differentiation functions present in GSL: gsl_diff_central, gsl_diff_backward and
       gsl_diff_forward. To compute the derivative, the central method uses values greater and smaller than the point at which the derivative is
       to be evaluated, while backward and forward use only values smaller and greater respectively. gsldiff() returns both the derivative and an
       absolute error estimate. The default  method is 'central', others can be specified by passing an option.

       Please check the GSL documentation for more information.

       Usage:

	 ($d,$abserr) = gsldiff($function_ref,$x,{Method => $method});

       Example:

	 #derivative using default method ('central')
	 ($d,$abserr) = gsldiff(&myf,3.3);

	 #same as above with method set explicitly
	 ($d,$abserr) = gsldiff(&myf,3.3,{Method => 'central'});

	 #using backward & forward methods
	 ($d,$abserr) = gsldiff(&myf,3.3,{Method => 'backward'});
	 ($d,$abserr) = gsldiff(&myf,3.3,{Method => 'forward'});

	 sub myf{
	   my ($x) = @_;
	   return exp($x);
	 }

BUGS

       Feedback is welcome. Log bugs in the PDL bug database (the database is always linked from http://pdl.perl.org).

SEE ALSO

       PDL

       The GSL documentation is online at

	 http://sources.redhat.com/gsl/ref/gsl-ref_toc.html

AUTHOR

       This file copyright (C) 2003 Andres Jordan <andresj@physics.rutgers.edu> 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.

       The GSL differentiation routines were written by David Morrison.

FUNCTIONS

   diff_central
	 Signature: (double x(); double [o] res(); double [o] abserr(); SV* funcion)

       info not available

       diff_central 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.

   diff_backward
	 Signature: (double x(); double [o] res(); double [o] abserr(); SV* funcion)

       info not available

       diff_backward 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.

   diff_forward
	 Signature: (double x(); double [o] res(); double [o] abserr(); SV* funcion)

       info not available

       diff_forward 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.

perl v5.12.1							    2010-07-05								   DIFF(3)