initial commit

+math/fftshift_2D.m

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+function [x,idx]  = fftshift_2D(x)
+% -----------------------------------------------------------------------
+% This file is part of the PTYCHOMAT Toolbox
+% Author: Michal Odstrcil, 2016
+% License: Open Source under GPLv3
+% Contact: ptychomat@gmail.com
+% Website: https://bitbucket.org/michalodstrcil/ptychomat
+% -----------------------------------------------------------------------
+% Description:   faster version of matlab fftshift to work for stack of
+% 2D images 
+% Inputs:  2D or stack of 2D images 
+% Outputs: 
+%   x - 2D or stack of 2D images after fftshift along first 2 dimensions
+%   idx - precalculated indices for fftshift operation
+
+
+numDims = 2;
+idx = cell(1, numDims);
+for k = 1:numDims
+    m = size(x, k);
+    p = ceil(m/2);
+    idx{k} = [p+1:m 1:p];
+end
+x = x(idx{:},:,:);
+
+
+end