Mercurial > octave-antonio
view scripts/general/interpft.m @ 20158:7503499a252b stable
doc: Update docstrings to have one sentence summary as first line.
Update scripts in audio, elfun, general, geometry, and image directories.
* scripts/audio/@audioplayer/__get_properties__.m,
scripts/audio/@audioplayer/audioplayer.m, scripts/audio/@audioplayer/get.m,
scripts/audio/@audioplayer/isplaying.m, scripts/audio/@audioplayer/play.m,
scripts/audio/@audioplayer/playblocking.m, scripts/audio/@audioplayer/set.m,
scripts/audio/@audioplayer/subsasgn.m, scripts/audio/@audioplayer/subsref.m,
scripts/audio/@audiorecorder/audiorecorder.m,
scripts/audio/@audiorecorder/get.m,
scripts/audio/@audiorecorder/getaudiodata.m,
scripts/audio/@audiorecorder/getplayer.m,
scripts/audio/@audiorecorder/isrecording.m,
scripts/audio/@audiorecorder/play.m, scripts/audio/@audiorecorder/record.m,
scripts/audio/@audiorecorder/recordblocking.m,
scripts/audio/@audiorecorder/set.m, scripts/audio/@audiorecorder/stop.m,
scripts/audio/@audiorecorder/subsasgn.m,
scripts/audio/@audiorecorder/subsref.m, scripts/audio/lin2mu.m,
scripts/audio/mu2lin.m, scripts/audio/record.m, scripts/audio/sound.m,
scripts/audio/soundsc.m, scripts/audio/wavread.m, scripts/audio/wavwrite.m,
scripts/elfun/cosd.m, scripts/elfun/sind.m, scripts/elfun/tand.m,
scripts/general/accumarray.m, scripts/general/accumdim.m,
scripts/general/bitcmp.m, scripts/general/bitget.m, scripts/general/bitset.m,
scripts/general/blkdiag.m, scripts/general/cart2pol.m,
scripts/general/cart2sph.m, scripts/general/cell2mat.m,
scripts/general/celldisp.m, scripts/general/chop.m,
scripts/general/circshift.m, scripts/general/common_size.m,
scripts/general/cplxpair.m, scripts/general/cumtrapz.m,
scripts/general/dblquad.m, scripts/general/deal.m, scripts/general/del2.m,
scripts/general/display.m, scripts/general/divergence.m,
scripts/general/fieldnames.m, scripts/general/flip.m,
scripts/general/flipdim.m, scripts/general/fliplr.m, scripts/general/flipud.m,
scripts/general/gradient.m, scripts/general/interp3.m,
scripts/general/interpft.m, scripts/general/interpn.m,
scripts/general/loadobj.m, scripts/general/logspace.m,
scripts/general/methods.m, scripts/general/nargchk.m,
scripts/general/narginchk.m, scripts/general/nargoutchk.m,
scripts/general/nextpow2.m, scripts/general/nthargout.m,
scripts/general/num2str.m, scripts/general/pol2cart.m,
scripts/general/polyarea.m, scripts/general/postpad.m,
scripts/general/prepad.m, scripts/general/profile.m, scripts/general/quadgk.m,
scripts/general/quadl.m, scripts/general/quadv.m, scripts/general/randi.m,
scripts/general/rat.m, scripts/general/repmat.m, scripts/general/rot90.m,
scripts/general/rotdim.m, scripts/general/saveobj.m, scripts/general/shift.m,
scripts/general/shiftdim.m, scripts/general/sortrows.m,
scripts/general/sph2cart.m, scripts/general/structfun.m,
scripts/general/subsindex.m, scripts/general/trapz.m,
scripts/general/triplequad.m, scripts/geometry/delaunayn.m,
scripts/geometry/dsearch.m, scripts/geometry/dsearchn.m,
scripts/geometry/griddata.m, scripts/geometry/griddata3.m,
scripts/geometry/griddatan.m, scripts/geometry/inpolygon.m,
scripts/geometry/rectint.m, scripts/geometry/tsearchn.m,
scripts/geometry/voronoi.m, scripts/geometry/voronoin.m,
scripts/help/__unimplemented__.m, scripts/help/doc.m,
scripts/help/doc_cache_create.m, scripts/help/get_first_help_sentence.m,
scripts/help/help.m, scripts/help/lookfor.m, scripts/help/print_usage.m,
scripts/help/type.m, scripts/help/which.m, scripts/image/autumn.m,
scripts/image/bone.m, scripts/image/brighten.m, scripts/image/cmpermute.m,
scripts/image/colorcube.m, scripts/image/contrast.m, scripts/image/cool.m,
scripts/image/copper.m, scripts/image/cubehelix.m, scripts/image/flag.m,
scripts/image/gmap40.m, scripts/image/gray.m, scripts/image/gray2ind.m,
scripts/image/hot.m, scripts/image/hsv.m, scripts/image/image.m,
scripts/image/imagesc.m, scripts/image/imfinfo.m, scripts/image/imformats.m,
scripts/image/imread.m, scripts/image/imshow.m, scripts/image/imwrite.m,
scripts/image/iscolormap.m, scripts/image/jet.m, scripts/image/lines.m,
scripts/image/ntsc2rgb.m, scripts/image/ocean.m, scripts/image/pink.m,
scripts/image/prism.m, scripts/image/rainbow.m, scripts/image/rgb2ntsc.m,
scripts/image/spinmap.m, scripts/image/spring.m, scripts/image/summer.m,
scripts/image/white.m, scripts/image/winter.m:
Update docstrings to have one sentence summary as first line.
Re-structure to have line lengths <= 80 chars.
author | Rik <rik@octave.org> |
---|---|
date | Sun, 03 May 2015 09:36:20 -0700 |
parents | 9fc020886ae9 |
children |
line wrap: on
line source
## Copyright (C) 2001-2015 Paul Kienzle ## ## This file is part of Octave. ## ## Octave 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. ## ## Octave 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 Octave; see the file COPYING. If not, see ## <http://www.gnu.org/licenses/>. ## -*- texinfo -*- ## @deftypefn {Function File} {} interpft (@var{x}, @var{n}) ## @deftypefnx {Function File} {} interpft (@var{x}, @var{n}, @var{dim}) ## ## Fourier interpolation. ## ## If @var{x} is a vector then @var{x} is resampled with @var{n} points. The ## data in @var{x} is assumed to be equispaced. If @var{x} is a matrix or an ## N-dimensional array, the interpolation is performed on each column of ## @var{x}. ## ## If @var{dim} is specified, then interpolate along the dimension @var{dim}. ## ## @code{interpft} assumes that the interpolated function is periodic, and so ## assumptions are made about the endpoints of the interpolation. ## @seealso{interp1} ## @end deftypefn ## Author: Paul Kienzle ## 2001-02-11 ## * initial version ## 2002-03-17 aadler ## * added code to work on matrices as well ## 2006-05-25 dbateman ## * Make it matlab compatiable, cutting out the 2-D interpolation function z = interpft (x, n, dim) if (nargin < 2 || nargin > 3) print_usage (); endif if (! (isscalar (n) && n == fix (n))) error ("interpft: N must be a scalar integer"); endif if (nargin == 2) if (isrow (x)) dim = 2; else dim = 1; endif endif nd = ndims (x); if (dim < 1 || dim > nd) error ("interpft: invalid dimension DIM"); endif perm = [dim:nd, 1:(dim-1)]; x = permute (x, perm); m = rows (x); inc = ceil (m/n); y = fft (x) / m; k = ceil (m / 2); sz = size (x); sz(1) = n * inc - m; idx = repmat ({':'}, nd, 1); idx{1} = 1:k; z = cat (1, y(idx{:}), zeros (sz)); idx{1} = k+1:m; z = cat (1, z, y(idx{:})); ## When m is an even number of rows, the FFT has a single Nyquist bin. ## If zero-padded above, distribute the value of the Nyquist bin evenly ## between the new corresponding positive and negative frequency bins. if (sz(1) > 0 && k == m/2) idx{1} = n * inc - k + 1; tmp = z(idx{:}) / 2; z(idx{:}) = tmp; idx{1} = k + 1; z(idx{:}) = tmp; endif z = n * ifft (z); if (inc != 1) sz(1) = n; z = inc * reshape (z(1:inc:end), sz); endif z = ipermute (z, perm); endfunction %!demo %! clf; %! t = 0 : 0.3 : pi; dt = t(2)-t(1); %! n = length (t); k = 100; %! ti = t(1) + [0 : k-1]*dt*n/k; %! y = sin (4*t + 0.3) .* cos (3*t - 0.1); %! yp = sin (4*ti + 0.3) .* cos (3*ti - 0.1); %! plot (ti, yp, 'g', ti, interp1(t, y, ti, "spline"), 'b', ... %! ti, interpft (y, k), 'c', t, y, "r+"); %! legend ("sin(4t+0.3)cos(3t-0.1)", "spline", "interpft", "data"); %!shared n,y %! x = [0:10]'; y = sin(x); n = length (x); %!assert (interpft (y, n), y, 20*eps); %!assert (interpft (y', n), y', 20*eps); %!assert (interpft ([y,y],n), [y,y], 20*eps); ## Test case with complex input from bug #39566 %!test %! x = (1 + j) * [1:4]'; %! y = ifft ([15 + 15*j; -6; -1.5 - 1.5*j; 0; -1.5 - 1.5*j; -6*j]); %! assert (interpft (x, 6), y, 10*eps); ## Test for correct spectral symmetry with even/odd lengths %!assert (max (abs (imag (interpft ([1:8], 20)))), 0, 20*eps); %!assert (max (abs (imag (interpft ([1:8], 21)))), 0, 21*eps); %!assert (max (abs (imag (interpft ([1:9], 20)))), 0, 20*eps); %!assert (max (abs (imag (interpft ([1:9], 21)))), 0, 21*eps); ## Test input validation %!error interpft () %!error interpft (1) %!error interpft (1,2,3) %!error <N must be a scalar integer> interpft (1,[2,2]) %!error <N must be a scalar integer> interpft (1,2.1) %!error <invalid dimension DIM> interpft (1,2,0) %!error <invalid dimension DIM> interpft (1,2,3)