PDL::GSL::INTERP(3pm)

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

6       PDL::GSL::INTERP - PDL interface to Interpolation routines in GSL
7

DESCRIPTION

9       This is an interface to the interpolation package present in the GNU
10       Scientific Library.
11

SYNOPSIS

13          use PDL;
14          use PDL::GSL::INTERP;
15
16          my $x = sequence(10);
17          my $y = exp($x);
18
19          my $spl = PDL::GSL::INTERP->init('cspline',$x,$y);
20
21          my $res = $spl->eval(4.35);
22          $res = $spl->deriv(4.35);
23          $res = $spl->deriv2(4.35);
24          $res = $spl->integ(2.1,7.4);
25

FUNCTIONS

27   init()
28       The init method initializes a new instance of INTERP. It needs as input
29       an interpolation type and two piddles holding the x and y values to be
30       interpolated. The GSL routines require that x be monotonically
31       increasing and a quicksort is performed by default to ensure that. You
32       can skip the quicksort by passing the option {Sort => 0}.
33
34       The available interpolation types are :
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36       · linear
37
38       · polynomial
39
40       · cspline (natural cubic spline)
41
42       · cspline_periodic  (periodic cubic spline)
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44       · akima (natural akima spline)
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46       · akima_periodic  (periodic akima spline)
47
48       Please check the GSL documentation for more information.
49
50       Usage:
51
52           $blessed_ref = PDL::GSL::INTERP->init($interp_method,$x,$y,$opt);
53
54       Example:
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56           $x = sequence(10);
57           $y = exp($x);
58
59           $spl = PDL::GSL::INTERP->init('cspline',$x,$y)
60           $spl = PDL::GSL::INTERP->init('cspline',$x,$y,{Sort => 1}) #same as above
61
62           # no sorting done on x, user is certain that x is monotonically increasing
63           $spl = PDL::GSL::INTERP->init('cspline',$x,$y,{Sort => 0});
64
65   eval()
66       The function eval returns the interpolating function at a given point.
67       By default it will barf if you try to extrapolate, to comply silently
68       if the point to be evaluated is out of range pass the option
69       {Extrapolate => 1}
70
71       Usage:
72
73           $result = $spl->eval($points,$opt);
74
75       Example:
76
77           my $res = $spl->eval($x)
78           $res = $spl->eval($x,{Extrapolate => 0}) #same as above
79
80           # silently comply if $x is out of range
81           $res = $spl->eval($x,{Extrapolate => 1})
82
83   deriv()
84       The deriv function returns the derivative of the interpolating function
85       at a given point. By default it will barf if you try to extrapolate, to
86       comply silently if the point to be evaluated is out of range pass the
87       option {Extrapolate => 1}
88
89       Usage:
90
91           $result = $spl->deriv($points,$opt);
92
93       Example:
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95           my $res = $spl->deriv($x)
96           $res = $spl->deriv($x,{Extrapolate => 0}) #same as above
97
98           # silently comply if $x is out of range
99           $res = $spl->deriv($x,{Extrapolate => 1})
100
101   deriv2()
102       The deriv2 function returns the second derivative of the interpolating
103       function at a given point. By default it will barf if you try to
104       extrapolate, to comply silently if the point to be evaluated is out of
105       range pass the option {Extrapolate => 1}
106
107       Usage:
108
109           $result = $spl->deriv2($points,$opt);
110
111       Example:
112
113           my $res = $spl->deriv2($x)
114           $res = $spl->deriv2($x,{Extrapolate => 0}) #same as above
115
116           # silently comply if $x is out of range
117           $res = $spl->deriv2($x,{Extrapolate => 1})
118
119   integ()
120       The integ function returns the integral of the interpolating function
121       between two points.  By default it will barf if you try to extrapolate,
122       to comply silently if one of the integration limits is out of range
123       pass the option {Extrapolate => 1}
124
125       Usage:
126
127           $result = $spl->integ($a,$b,$opt);
128
129       Example:
130
131           my $res = $spl->integ($a,$b)
132           $res = $spl->integ($a,$b,{Extrapolate => 0}) #same as above
133
134           # silently comply if $a or $b are out of range
135           $res = $spl->eval($a,$b,{Extrapolate => 1})
136

BUGS

138       Feedback is welcome.
139

AUTHOR

148       This file copyright (C) 2003 Andres Jordan
149       <andresj@physics.rutgers.edu> All rights reserved. There is no
150       warranty. You are allowed to redistribute this software/documentation
151       under certain conditions. For details, see the file COPYING in the PDL
152       distribution. If this file is separated from the PDL distribution, the
153       copyright notice should be included in the file.
154
155       The GSL interpolation module was written by Gerard Jungman.
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159perl v5.12.3                      2011-03-31                         INTERP(3)

NAME

DESCRIPTION

SYNOPSIS

FUNCTIONS

BUGS

SEE ALSO

AUTHOR