Re: bsearch in octave

[LUK ShunTim]

On 2005-06-25 17:35, Geraint Paul Bevan wrote:
> LUK ShunTim wrote:
>
> > > On 2005-06-25 1:00, Jeff Abrahamson wrote:
> > >
> > >
> > > > I want to find the last element in a row vector that is less than a
> > > > given value.  I want the index of this value.  In C, for example, I'd
> > > > use bsearch (binary search), thus the subject on my mail.

[snipped]

> > > This seems to be what you want.
> > >
> > >
> > > > > a=[1,3,7,15];
> > > > > index=find(a>6)(1) - 1
>
>
> That doesn't find the last matching number. If I understand the question
> correctly, in the larger search space
>
> octave> a=[1,3,7,15,4,19];
>
> the answer should be the last number less than or equal to 6, which is 4
> in position 5, but
>
> octave> index=find(a>6)(1) - 1
> index = 2
>
>
> The following function works,
>
> function i = bsearch(x,n);
>   i = find(x<=n)(end);
> end

[snipped]

Thanks for pointing it out. I mis-read the question as finding the index 
of first element that has a value less than the given value.

And I learn what is a bsearch now; but I don't understand how does 
"binary" comes in?

Regards,
ST
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