Re: Correlate and NAN

[Ben Tupper <btupper(at)bigelow.org>]

Thanks Pavel and Andy,

I have deNANed the data as you suggested.

Ben

Andy Loughe wrote:

> Why not simply perform the correlation on a subset of the larger arrays,
> that portion with the NaNs removed?  Something like:
>
> indices = [ where( finite(dataset1) eq 1 ), where( finite(dataset2) eq 2
> ) ]
>
> common_indices = indices( UNIQ(indices, sort(indices)) )
>
> Result  = CORRELATE( dataset1(common_indices), dataset2(common_indices)
> )
>
> Ben Tupper wrote:
> >
> > Hello,
> >
> > I have two datasets that I would like to correlate using the CORRELATE
> > function.  Each dataset has some members flagged as NANs; the NANs are
> > not neccessarily coincident.   The online documentation makes no mention
> > of NAN-handling, but the procedure in the lib directory indicates (see
> > modifications history) that it handles NANs (although there is no
> > keyword for it).  It doesn't really handle NANs the way I expect it
> > to.   For example, repeated calls to the TOTAL function don't set the
> > keyword NAN, so TOTAL doesn't check for NANs.
> >
> > I'm not sure if it is reasonable to involve NANs in a correlation... but
> > it seems reasonable to request that the routine ignore NANs in the input
> > arguments.
> >
> > Is there a simple solution to this NAN-jam?
> >
> > Thanks,
> >
> > Ben
> >
> > --
> > Ben Tupper
> > Bigelow Laboratory for Ocean Sciences
> > 180 McKown Point Rd.
> > W. Boothbay Harbor, ME 04575
> > btupper@bigelow.org
>
> --
> Andrew Loughe =====================================================
> NOAA/OAR/FSL/AD   R/FS5  |  email: loughe@fsl.noaa.gov
> 325 Broadway             |  wwweb: www-ad.fsl.noaa.gov/users/loughe
> Boulder, CO  80305-3328  |  phone: 303-497-6211   fax: 303-497-6301

--
Ben Tupper
Bigelow Laboratory for Ocean Sciences
180 McKown Point Rd.
W. Boothbay Harbor, ME 04575
btupper@bigelow.org