function [x,res] = omp(b,A,k)
% compute k-sparse approximation to b with matrix A using Matching pursuit
[m,N] = size(A);
x = zeros(N,1);
res = b;
support = [];
A_get=zeros(m,k);
for i=1:k
corr = (A')*res;
[c,n] = max(abs(corr));
support(end+
function [x,res] = omp(b,A,k)
% compute k-sparse approximation to b with matrix A using Matching pursuit
[m,N] = size(A);
x = zeros(N,1);
res = b;
support = [];
A_get=zeros(m,k);
for i=1:k
corr = (A')*res;
[c,n] = max(abs(corr));
support(end+