/usr/share/octave/packages/signal-1.3.2/data2fun.m is in octave-signal 1.3.2-5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 | ## Copyright (c) 2011 Juan Pablo Carbajal <carbajal@ifi.uzh.ch>
##
## This program is free software; you can redistribute it and/or modify it under
## the terms of the GNU General Public License as published by the Free Software
## Foundation; either version 3 of the License, or (at your option) any later
## version.
##
## This program is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
## details.
##
## You should have received a copy of the GNU General Public License along with
## this program; if not, see <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @deftypefn {Function File} {[@var{fhandle}, @var{fullname}] =} data2fun (@var{ti}, @var{yi})
## @deftypefnx {Function File} {[@dots{}] =} data2fun (@var{ti}, @var{yi},@var{property},@var{value})
## Creates a vectorized function based on data samples using interpolation.
##
## The values given in @var{yi} (N-by-k matrix) correspond to evaluations of the
## function y(t) at the points @var{ti} (N-by-1 matrix).
## The data is interpolated and the function handle to the generated interpolant
## is returned.
##
## The function accepts property-value pairs described below.
##
## @table @samp
## @item file
## Code is generated and .m file is created. The @var{value} contains the name
## of the function. The returned function handle is a handle to that file. If
## @var{value} is empty, then a name is automatically generated using
## @code{tmpnam} and the file is created in the current directory. @var{value}
## must not have an extension, since .m will be appended.
## Numerical value used in the function are stored in a .mat file with the same
## name as the function.
##
## @item interp
## Type of interpolation. See @code{interp1}.
##
## @end table
##
## @seealso{interp1}
## @end deftypefn
function [fhandle fullfname] = data2fun( t, y, varargin)
## Check input arguments
interp_args = {"spline"};
given = struct("file",false);
if ~isempty(varargin)
## Arguments
interp_args = varargin;
opt_args = fieldnames (given);
[tf idx] = ismember( opt_args, varargin);
for i=1:numel(opt_args)
given.(opt_args{i}) = tf(i);
endfor
if given.file
## FIXME: check that file will be in the path. Otherwise fhabdle(0) fails.
if !isempty(varargin{idx(1)+1})
[DIR fname] = fileparts(varargin{idx(1)+1});
else
[DIR fname] = fileparts (tmpnam (pwd (),"agen_"));
endif
interp_args(idx(1)+[0 1]) = [];
endif
if isempty(interp_args)
interp_args = {"spline"};
endif
endif
pp = interp1 (t, y, interp_args{end}, 'pp');
if given.file
fullfname = fullfile (DIR,[fname ".m"]);
save("-binary",[fullfname(1:end-2) ".mat"],"pp");
bodystr = [" persistent pp\n" ...
" if isempty(pp)\n" ...
" pp = load([mfilename()" ' ".mat"' "]).pp;\n"...
" end\n\n" ...
" z = ppval(pp, x);"];
strfunc = generate_function_str(fname, {"z"}, {"x"}, bodystr);
fid = fopen ( fullfile (DIR,[fname ".m"]), "w");
fprintf (fid, "%s", strfunc);
fclose (fid);
disp(["Function generated: " fullfname ]);
fhandle = eval(["@" fname]);
else
fullfname = "";
fhandle = @(t_) ppval (pp, t_);
endif
endfunction
function str = generate_function_str(name, oargs, iargs, bodystr)
striargs = cell2mat ( cellfun (@(x) [x ", "], iargs, "UniformOutput", false));
striargs = striargs(1:end-2);
stroargs = cell2mat ( cellfun (@(x) [x ", "], oargs, "UniformOutput", false));
stroargs = stroargs(1:end-2);
if !isempty (stroargs)
str = ["function [" stroargs "] = " name "(" striargs ")\n\n" bodystr ...
"\n\nendfunction"];
else
str = ["function " name "(" striargs ")\n\n" bodystr ...
"\n\nendfunction"];
endif
endfunction
%!shared t, y
%! t = linspace(0,1,10);
%! y = t.^2 - 2*t + 1;
%!test
%! fhandle = data2fun(t,y);
%! assert(y,fhandle(t));
%!test
%! [fhandle fname] = data2fun(t,y,"file","testdata2fun");
%! yt = testdata2fun(t);
%!
%! assert(y,yt);
%! assert(y,fhandle(t));
%!
%! delete(fname);
%! delete([fname(1:end-2) ".mat"]);
%!test
%! [fhandle fname] = data2fun(t,y,"file","");
%! yt = testdata2fun(t);
%!
%! assert(y,yt);
%! assert(y,fhandle(t));
%!
%! delete(fname);
%! delete([fname(1:end-2) ".mat"]);
%!test
%! [fhandle fname] = data2fun(t,y,"file","testdata2fun","interp","linear");
%! yt = testdata2fun(t);
%!
%! assert(y,yt);
%! assert(y,fhandle(t));
%!
%! delete(fname);
%! delete([fname(1:end-2) ".mat"]);
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