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function ifftreal_ref_mat(filepath)
% Save the output of the ifftreal function into a .mat file for some example
% inputs
if nargin < 1
filepath = pwd();
end
filename=[filepath, '/ifftreal_ref.mat'];
disp(filename)
% NOTE: ifftreal is buggy in LTFAT 2.1.0 for Octave
% For example:
% ifftreal(rand(8,1), 32, 1);
% crashes octave.
% It seems that the crash arises when N is too big compared to the length of the
% data along the dimension used to do the transform.
% So we are limited in the values that can be used as N in this test.
%
% In general it seems that values of N different from the one used to compute
% fftreal leads to wrong results for arrays having 2D or more.
% For example :
%>> ifftreal([1,2;3,4], 4, 1)
%ans =
%
% 2.25000 1.00000
% -0.25000 1.00000
% -0.75000 1.00000
% -0.25000 1.00000
%
%>> ifftreal([1;3], 4, 1)
%ans =
%
% 1.75000
% 0.25000
% -1.25000
% 0.25000
%
%>> ifftreal([2;4], 4, 1)
%ans =
%
% 2.50000
% 0.50000
% -1.50000
% 0.50000
%
%>> a=rand(3)+i*rand(3);
%>> ifftreal(a(:,3), 2, 1)
%ans =
%
% 0.37296
% 0.34901
%
%>> ifftreal(a, 2, 1)
%ans =
%
% 0.805618 0.087949 0.491575
% -0.115312 -0.022500 0.413780
inputs_names = {'c', 'N', 'dim'};
sizes = {[8; 1], [13; 1]};
nb_outputs = 1;
outputs = cell(1, nb_outputs);
data = {};
inputs={};
for ind = 1:length(sizes)
size = sizes{ind};
inputs{1} = rand(size)+i*rand(size);
for ind_N = -3:3
for dim = 1:(length(size)-1)
inputs{3} = dim;
inputs{2} = (size(dim)-1)*2 + ind_N;
[outputs{:}] = ifftreal(inputs{:});
inputs{3} = dim-1; % needed because Python dimensions start at 0
data{end+1} = {inputs_names, inputs, outputs};
end
end
end
save(filename, 'data', '-V6');
end
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