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
29       The init method initializes a new instance of INTERP. It needs as input
30       an interpolation type and two piddles holding the x and y values to be
31       interpolated. The GSL routines require that x be monotonically increas‐
32       ing and a quicksort is performed by default to ensure that. You can
33       skip the quicksort by passing the option {Sort => 0}.
34
35       The available interpolation types are :
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37       · linear
38
39       · polynomial
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41       · cspline (natural cubic spline)
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43       · cspline_periodic  (periodic cubic spline)
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45       · akima (natural akima spline)
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47       · akima_periodic  (periodic akima spline)
48
49       Please check the GSL documentation for more information.
50
51       Usage:
52
53           $blessed_ref = PDL::GSL::INTERP->init($interp_method,$x,$y,$opt);
54
55       Example:
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57           $x = sequence(10);
58           $y = exp($x);
59
60           $spl = PDL::GSL::INTERP->init('cspline',$x,$y)
61           $spl = PDL::GSL::INTERP->init('cspline',$x,$y,{Sort => 1}) #same as above
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63           # no sorting done on x, user is certain that x is monotonically increasing
64           $spl = PDL::GSL::INTERP->init('cspline',$x,$y,{Sort => 0});
65
66       eval()
67
68       The function eval returns the interpolating function at a given point.
69       By default it will barf if you try to extrapolate, to comply silently
70       if the point to be evaluated is out of range pass the option {Extrapo‐
71       late => 1}
72
73       Usage:
74
75           $result = $spl->eval($points,$opt);
76
77       Example:
78
79           my $res = $spl->eval($x)
80           $res = $spl->eval($x,{Extrapolate => 0}) #same as above
81
82           # silently comply if $x is out of range
83           $res = $spl->eval($x,{Extrapolate => 1})
84
85       deriv()
86
87       The deriv function returns the derivative of the interpolating function
88       at a given point. By default it will barf if you try to extrapolate, to
89       comply silently if the point to be evaluated is out of range pass the
90       option {Extrapolate => 1}
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92       Usage:
93
94           $result = $spl->deriv($points,$opt);
95
96       Example:
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98           my $res = $spl->deriv($x)
99           $res = $spl->deriv($x,{Extrapolate => 0}) #same as above
100
101           # silently comply if $x is out of range
102           $res = $spl->deriv($x,{Extrapolate => 1})
103
104       deriv2()
105
106       The deriv2 function returns the second derivative of the interpolating
107       function at a given point. By default it will barf if you try to
108       extrapolate, to comply silently if the point to be evaluated is out of
109       range pass the option {Extrapolate => 1}
110
111       Usage:
112
113           $result = $spl->deriv2($points,$opt);
114
115       Example:
116
117           my $res = $spl->deriv2($x)
118           $res = $spl->deriv2($x,{Extrapolate => 0}) #same as above
119
120           # silently comply if $x is out of range
121           $res = $spl->deriv2($x,{Extrapolate => 1})
122
123       integ()
124
125       The integ function returns the integral of the interpolating function
126       between two points.  By default it will barf if you try to extrapolate,
127       to comply silently if one of the integration limits is out of range
128       pass the option {Extrapolate => 1}
129
130       Usage:
131
132           $result = $spl->integ($a,$b,$opt);
133
134       Example:
135
136           my $res = $spl->integ($a,$b)
137           $res = $spl->integ($a,$b,{Extrapolate => 0}) #same as above
138
139           # silently comply if $a or $b are out of range
140           $res = $spl->eval($a,$b,{Extrapolate => 1})
141

BUGS

143       Feedback is welcome.
144

AUTHOR

153       This file copyright (C) 2003 Andres Jordan <andresj@physics.rut‐
154       gers.edu> All rights reserved. There is no warranty. You are allowed to
155       redistribute this software/documentation under certain conditions. For
156       details, see the file COPYING in the PDL distribution. If this file is
157       separated from the PDL distribution, the copyright notice should be
158       included in the file.
159
160       The GSL interpolation module was written by Gerard Jungman.
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164perl v5.8.8                       2006-12-02                         INTERP(3)

NAME

DESCRIPTION

SYNOPSIS

FUNCTIONS

BUGS

SEE ALSO

AUTHOR