Re: zero crossing determination in octave?

[sjeffrey000]

Yes, that's exactly what I wanted.  I just overlooked the obvious answer.
Thanks,
Steve
----- Original Message ----- 
From: "Søren Hauberg" <address@hidden>
To: "Steve Jeffrey" <address@hidden>
Cc: <address@hidden>
Sent: Monday, February 16, 2009 3:59 PM
Subject: Re: zero crossing determination in octave?


> fre, 13 02 2009 kl. 08:56 -0800, skrev Steve Jeffrey:
> > How can it be modified to find the crossings of an arbitrary trigger
> > parameter instead of 0 where there could be lots of noise? I had a look,
> > but it's definitely a non-trivial task for me.
>
> I'm not quite sure I understand. The function I sent could find zero
> crossings in a function given by a matrix. Do you just want to find
> positions where such a function crosses a different value rather than
> zero? I.e. find places where
>
>  f (x, y) == alpha
>
> instead of
>
>  f (x, y) == 0
>
> ? If so, you can just use the function I sent to find
>
>  f (x, y) - alpha == 0
>
> i.e. just subtract alpha from your matrix, and then find zero crossings.
> Is that what you wanted? Otherwise you'll have to be more specific.
>
> S?ren