[Scilab-users] is vectorization possible

[Serge Steer]

Le 27/09/2016 à 09:08, paul.carrico at free.fr a écrit :
> Hi All
>
> Is the vectorization possible for the example herebellow? everything I 
> tried failed !
if a is a vector, it is quite straight forward: sum(matrix(a,w,-1),1).'
k=100;a=rand(k,1);w=5;n=k/w;
tmp = zeros(n,1);
for i = 1 : n
tmp(i,1) = sum(a( [1 + (i-1)*w : i*w],:));
end
tmp-sum(sum(matrix(a,w,n,-1),3),1).'


If a is matrix it is more tricky: sum(sum(matrix(a,w,n,-1),3),1).'
k=100;a=rand(k,4);w=5;n=k/w;

tmp = zeros(n,1);
for i = 1 : n
tmp(i,1) = sum(a( [1 + (i-1)*w : i*w],:));
end
tmp-sum(sum(matrix(a,w,n,-1),3),1).'


Serge
>
> Thanks for any help
>
> Paul
>
> ##################################################################
> mode(0)
>
> k = 100;
> a = rand(k,1);
>
> w = 5;
> n = (k/w);
>
> i = [1 : n]';
>
> tmp = zeros(n,1);
>
> // using vectorization
> tmp(i,1) = sum(a( [1 + (i-1)*n : i*n],:)
> abort
>
>
> // same using a loop
> for i = 1 : n
> tmp(i,1) = sum(a( [1 + (i-1)*w : i*w],:));
> end
>
> tmp
>
>
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