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rbmatlab 0.10.01
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general/vecmat/spblkdiag.m
00001 function M = spblkdiag(blocks) 00002 %function M = spblkdiag(blocks) 00003 % 00004 % function generating efficiently a sparse matrix containing 00005 % subblocks blocks(:,:,i) as block i along the diagonal. 00006 % this is 1000 times faster than blkdiag!!!! 00007 % 00008 % Bernard Haasdonk 31.8.2009 00009 00010 [n,m,k] = size(blocks); 00011 00012 row_ind = (1:n)'*ones(1,m*k); 00013 row_offs =(ones(n*m,1)*(0:(k-1)))*n; 00014 row_ind = row_ind(:)+row_offs(:); 00015 00016 col_ind = ones(n,1)*(1:(m*k)); 00017 col_ind = col_ind(:); 00018 00019 M = sparse(row_ind,col_ind,blocks(:));%| \docupdate
