Re: remove for-loop from following code

[Juan Pablo Carbajal]

On Sun, Nov 6, 2011 at 9:52 AM, Stefaan Himpe <address@hidden> wrote:
>
>>> function [Ytr] = ytransform(D, Y)
>>>  [rows, cols] = size(Y);
>>>  for row = 1:rows
>>>    Ytr(:,row) = (1:D == Y(row));
>>>  endfor
>>> endfunction
>>>
>>> Is there a way to do implement this without for loop over all rows of Y?
>
>>
>> Try,
>> N = lenth(Y);
>> subs = [(1:N).' Y(:)];
>> Ytr = accumarray (subs, ones(N,1));
>
> Hello,
>
> Thanks for your reply.
> After scanning the octave documentation once more I finally arrived at the
> following solution (which uses some special provisions to create permutation
> matrices):
>
> function [Ytr] = ytransformed(K,Y)
>  Ytr = eye(K)(Y',:);
> endfunction
>
> Thanks for your reply!
> Best regards,
> Stefaan.
>
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>
Nice solution.
Now, isn't K == max(Y)? You may reduce the arity of your funcion, if so.


-- 
M. Sc. Juan Pablo Carbajal
-----
PhD Student
University of Zürich
http://ailab.ifi.uzh.ch/carbajal/