%% find known submatrix in large matrix
% will find all instances
sourceMat = magic(15); % example source matrix
targMat = [218 10 27; 9 26 43]; % example target submatrix
[s1, s2] = size(targMat); % size of target
searchGrid = zeros(size(sourceMat,1)-s1, size(sourceMat,2)-s2); % grid of possible locations
for ii = 1:size(sourceMat,1)-s1 % loop over first dimension
for jj = 1:size(sourceMat,2)-s2 % loop over second dimension
subMat = sourceMat(ii:ii+s1-1,jj:jj+s2-1); % look at this region in source
diff = sum(squash(subMat - targMat)); % compare target to this region
if diff == 0 % is this region the same as target?
searchGrid(ii,jj) = 1; % record success!
end
end
end
[rows, cols] = find(searchGrid); % coordinate pairs of top corner of matching areas
horzcat(rows, cols)
