Re: vectorise matrix slice extraction

[Francesco Potorti`]

>> Is there a way to efficiently remove the for loop in this assignment?
>>
>>  for jj = length(pple):-1:1
>>    llk(:,:,:,jj) = ll(:,:,:,pple(jj),tple(jj));
>>  endfor
>
>n = length (pple);
>i = sub2ind(size (ll) (4:5), pple, tple);
>llk(:,:,:,1:n) = ll(:,:,:,i);

Yes, this is it!  No reshape, no temp variables.  I had never realised
that you can access a 5-d matrix with four indices.  It is even simpler
than the above:

jj = sub2ind(size(ll)(4:5), pple, tple);
llk = ll(:,:,:,jj);

It is slightly faster than the for loop, maybe more elegant, maybe less
clear.

Thanks

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