Re: fastest way to test a logical vector

[Carlo de Falco]

On 20 Jan 2010, at 12:42, Dupuis wrote:

> Hello,
>
> I'm analysing a signal where outliers are not uncommon. So the main  
> loop
> contains a number of test like
>
> sum(x(indi-(1:4)) >= 0) >= 2 && sum(x(indi+(1:4)) <= 2) >= 2,
>
> I tried to optimise x and indi as int16, so the types are
> x(indi-(1:4)) vector of int16
> x(indi-(1:4)) >= 0 vector of logical
> sum(x(indi-(1:4)) >= 0) double
>
> Is there a way to avoid, in the last operation, the logical -> double
> conversion ? any() doesn't fit the requirement, as it test for one  
> value. I
> thinked about
> sort(x(indi-(1:4)) >= 0))(3) == 1
> But this implies to call sort at each test. Does someone see a faster
> solution ? I'm working with octave3.2
>
> Regards
>
> Pascal

you could use

numel (find (x(indi-(1:4)))) >= 2

c.