Yes, read up on Include which would permit you to 'exclude' points outside your range. You do the calculation you propose by:
Mark("positions"); //makes a copy of 'positions' in the 'data' component
Compute(mag(a) > b); //provide the field to the 'a' input and some scalar value to 'b', like a Scalar Interactor
Include(min=1, max=1,cull=1)
Do not Unmark or the flag values (0|1) will overwrite the 'positions'.
If you do have 'data' that needs to be available after Include, this problem gets trickier to manage, so write again.
On Wednesday, Sep 1, 2004, at 20:33 America/New_York, Gan Uesli Starling wrote:
ShowPositions improved the memory situation. But the stray dots are________________________________
often more interesting than the cloud center. And being so small, those
get lost from view. Might be better to reduce points in the very
center of the cloud and keep the outer strays nice and big.
So, then...can I have OpenDX itself eliminate some data according to a
formula something like...
if SQRT( X^2 + Y^2 + Z^2 ) < some_value
...so as to ignore any data points clustered inside a given sphere
about the origin? Say, put a function like that between the spreadsheet
module and the three mark modules?
One pair of my plots look like this...
http://starling.us/foo/sx01ds_vs_sy01ds_diagonal.tiff
...if any are curious.
At present larger data sets run out of memory. I can manage, if need
be, the extraction in Perl. But it might be instructive to learn how
a module in OpenDX could do it sans the manual step.
I appreciate the suggestion below about the data reduction pre-step. But
I'm kind of stuck with scatter plots which, I am informed, must be float.
TIA,
Gan
--
Mistera Sturno - Rarest Extinct Bird
<(+)__ Gan Uesli Starling
((__/)=- Kalamazoo, MI, USA
`||`
++ http://starling.us
Chris Pelkie
Vice President
Conceptual Reality Presentations, Inc.
30 West Meadow Drive
Ithaca, NY 14850
