/usr/share/octave/packages/signal-1.3.2/idst.m is in octave-signal 1.3.2-1+b1.
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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 | ## Author: Paul Kienzle <pkienzle@users.sf.net> (2006)
## This program is granted to the public domain.
## -*- texinfo -*-
## @deftypefn {Function File} {@var{y} =} idst (@var{x})
## @deftypefnx {Function File} {@var{y} =} idst (@var{x}, @var{n})
## Computes the inverse type I discrete sine transform of @var{y}. If @var{n} is
## given, then @var{y} is padded or trimmed to length @var{n} before computing
## the transform. If @var{y} is a matrix, compute the transform along the
## columns of the the matrix.
## @seealso{dst}
## @end deftypefn
function x = idst (y, n)
if (nargin < 1 || nargin > 2)
print_usage;
endif
if nargin == 1,
n = size(y,1);
if n==1, n = size(y,2); endif
endif
x = dst(y, n) * 2/(n+1);
endfunction
%!test
%! x = log(gausswin(32));
%! assert(x, idst(dst(x)), 100*eps)
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