comp.lang.idl-pvwave archive: archive » matrix multiplication

Home » Public Forums » archive » matrix multiplication

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

matrix multiplication [message #91808]

Sun, 30 August 2015 11:04

siumtesfai
Messages: 62
Registered: April 2013

Member

Hi all

I have two dimensional data (2Ddata) with missing value ( NAN).

sz=size(2Ddata)

How can I calculate matrix multiplication by excluding the missing data

matrix = (1/ntime-1) * (Double(2Ddata) ## Transpose(2Ddata))

Best regards

Report message to a moderator

Re: matrix multiplication [message #91841 is a reply to message #91808]

Thu, 03 September 2015 10:02

Jeremy Bailin
Messages: 618
Registered: April 2008

Senior Member

On Sunday, August 30, 2015 at 1:04:04 PM UTC-5, siumt...@gmail.com wrote:
> Hi all
>
> I have two dimensional data (2Ddata) with missing value ( NAN).
>
> sz=size(2Ddata)
>
>
>
> How can I calculate matrix multiplication by excluding the missing data
>
>
> matrix = (1/ntime-1) * (Double(2Ddata) ## Transpose(2Ddata))
>
>
> Best regards

What are you expecting to happen where the missing data are? It's not well-defined what a missing value times a non-missing value is -- IDL will give you NaN there, which is the only sensible answer I can see. If you're expecting something else, what fundamentally do you expect there?

-Jeremy.

Report message to a moderator

Previous Topic:	Print version of Modern IDL
Next Topic:	FG PLOT options HISTOGRAM/STAIRSTEP but for horizontal display?

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Wed Oct 08 07:16:52 PDT 2025

Total time taken to generate the page: 0.00449 seconds