How to map elements?

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Rui
Rui on 9 Jan 2013
Hello everybody,
I am cleaning some code and I came across with the following and I hope you guys can give some extra insigths.
The code is working like shown but I'd like to simplify it somehow.
  • Both hil and rom are allocated.
  • schema contains indexes. The value of these indexes is no greater than the dimensions of hil and rom.
  • hil initially is zeros and I want to fulfill it with values from rom in due position.
for i = 1:M
for j = 1:N
hil(i,schema(i,:,j),j) = rom(i,schema(i,:,j),j);
end
end
Thanks,
Rui

Accepted Answer

Matt J
Matt J on 9 Jan 2013
Edited: Matt J on 9 Jan 2013
I think your current approach is optimum.
The only exception is if you're going to repeat this for different rom, but the same schema. Then I would do
[ii,jj]=ndgrid(1:N);
ss=scheme(1:N,:,1:N);
idx=sub2ind(size(rom),ii(:),ss(:),jj(:) );
and now you can repeatedly do
hil(idx)=rom(idx)
reusing idx for different rom.

More Answers (1)

Rui
Rui on 10 Jan 2013
Thanks Matt. In my case I am not able to redefine the number of elements on any dimension (if just 1 dimension could be redimensioned, we could get rid off 1 cycle, and so on), so I suppose I will have to live with that.
Cheers, Rui

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