Can anyone show me how I can avoid following for loops

*Hello everyone,

Can anyone show me how I can avoid following for loops.

Thanks!*

     mth=0;
      nth=0;

      for i=1:1000
          ML = [1,2;3,4];
          for ix=1:size(ML,1)
              for iy=1:size(ML,2)
                  M(mth+ix,nth+iy)=ML(ix,iy);
              end
          end
          mth = mth+size(ML,1);
          nth = nth+size(ML,2);
      end

Answer 1

[Matt Fig]

Here is a one approach:

M =  diag(repmat([1 4],1,1000)) +...
     diag([repmat([2 0],1,999) 2],1) +...
     diag([repmat([3 0],1,999) 3],-1);

And another:

M = diag(repmat([1 4],1,1000));
M(2001:2001:end) = [repmat([2 0],1,999) 2];
M(2:2001:end) = [repmat([3 0],1,999) 3];

[hung lequang]

Very nice approach. Thanks again.

Answer 2

[Walter Roberson]

for iy=1:size(ML,2)
  M(mth+ix,nth+iy)=ML(ix,iy);
end

can be written as

MLc = size(ML,2);
M(mth+ix, nth:nth+MLc-1) = ML(ix, 1:MLc);

[Daniel Shub]

Are you sure? If nth is 0 and MLc is 2, nth:nth+MLc-1 gives [0, 1] which causes indexing problems. I think it is nth+(1:MLc) on the RHS.

[Walter Roberson]

Yes, that would make sense on the LHS.

[Daniel Shub]

Yes, LHS not RHS...