spreadadj.m

Matlab时频分析工具箱,希望能对大家有所帮助啊

function cadj=spreadadj(coef);
%SPREADADJ  Symbol of adjoint preading function.
%   Usage: cadj=spreadadj(c);
%
%   cadj=SPREADADJ(c) will compute the symbol cadj of the spreading
%   operator that is the adjoint of the spreading operator with symbol c.
%
%   SEE ALSO:  SPREADOP, TCONV, SPREADFUN, SPREADINV

% 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/>.

error(nargchk(1,1,nargin));

if ndims(coef)>2 || size(coef,1)~=size(coef,2)
    error('Input symbol coef must be a square matrix.');
end;

L=size(coef,1);

% The adjoint symbol is just as sparse as the symbol itself. More carefull
% coding could expose this.

coef=fft(coef);

for ii=0:L-1
    for jj=0:L-1
        cadj(ii+1,jj+1)=conj(coef(mod(ii-jj,L)+1,mod(-jj,L)+1));
    end;
end;

cadj=ifft(cadj);