1MROOT(3)              User Contributed Perl Documentation             MROOT(3)
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NAME

6       PDL::GSL::MROOT - PDL interface to multidimensional root-finding
7       routines in GSL
8

DESCRIPTION

10       This is an interface to the multidimensional root-finding package
11       present in the GNU Scientific Library.
12
13       At the moment there is a single function gslmroot_fsolver which
14       provides an interface to the algorithms in the GSL library that do not
15       use derivatives.
16

SYNOPSIS

18          use PDL;
19          use PDL::GSL::MROOT;
20
21          my $init = pdl (-10.00, -5.0);
22          my $epsabs = 1e-7;
23
24
25         $res = gslmroot_fsolver($init, \&rosenbrock,
26                                 {Method => 0, EpsAbs => $epsabs});
27
28
29         sub rosenbrock{
30            my ($x) = @_;
31            my $a = 1;
32            my $b = 10;
33            my $y = zeroes($x);
34
35            my $y0 = $y->slice(0);
36            $y0 .=  $a * (1 - $x->slice(0));
37
38            my $y1 = $y->slice(1);
39            $y1 .=  $b * ($x->slice(1) - $x->slice(0)**2);
40
41            return $y;
42         }
43

FUNCTIONS

45   fsolver_meat
46         Signature: (double  xfree(n);   double epsabs(); int method(); SV* function1)
47
48       info not available
49
50       fsolver_meat does not process bad values.  It will set the bad-value
51       flag of all output piddles if the flag is set for any of the input
52       piddles.
53
54   gslmroot_fsolver
55       Multidimensional root finder without using derivatives
56
57       This function provides an interface to the multidimensional root
58       finding algorithms in the GSL library. It takes a minimum of two
59       argumennts: a piddle $init with an initial guess for the roots of the
60       system and a reference to a function. The latter function must return a
61       piddle whose i-th element is the i-th equation evaluated at the vector
62       x (a piddle which is the sole input to this function). See the example
63       in the Synopsis above for an illustration. The function returns a
64       piddle with the roots for the system of equations.
65
66       Two optional arguments can be specified as shown below. One is Method,
67       which can take the values 0,1,2,3. They correspond to the 'hybrids',
68       'hybrid', 'dnewton' and 'broyden' algorithms respectively (see GSL
69       documentation for details). The other optional argument is Epsabs,
70       which sets the absolute accuracy to which the roots of the system of
71       equations are required. The default value for Method is 0 ('hybrids'
72       algorithm) and the default for Epsabs is 1e-3.
73
74       Usage:
75
76          $res = gslmroot_fsolver($init, $function_ref,
77                                  [{Method => $method, Epsabs => $epsabs}]);
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SEE ALSO

80       PDL
81
82       The GSL documentation is online at
83
84         http://www.gnu.org/software/gsl/manual/
85

AUTHOR

87       This file copyright (C) 2006 Andres Jordan <ajordan@eso.org> and Simon
88       Casassus <simon@das.uchile.cl> All rights reserved. There is no
89       warranty. You are allowed to redistribute this software/documentation
90       under certain conditions. For details, see the file COPYING in the PDL
91       distribution. If this file is separated from the PDL distribution, the
92       copyright notice should be included in the file.
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96perl v5.28.0                      2018-07-23                          MROOT(3)