comp.lang.idl-pvwave archive: archive

Home » Public Forums » archive » Re: Matrix rank

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

Re: Matrix rank [message #57537 is a reply to message #57536]

Fri, 14 December 2007 08:28

Vince Hradil
Messages: 574
Registered: December 1999

Senior Member

On Dec 14, 9:42 am, Wox <nom...@hotmail.com> wrote:
> On Fri, 14 Dec 2007 06:35:11 -0800 (PST), Vince Hradil
>
> <hrad...@yahoo.com> wrote:
>> IDL can do SVD, can you get the rank from that? Look up SVDC in the
>> docs.
>
> I could do this, but maybe there's a better way?
>
> ; A: integers
> ; B: floats
> A = [[ 0,0,1], $
> [ 0,1,0], $
> [ 0,0,0]]
> B = [0.25,0.5,1]
>
> ; Decompose A
> SVDC, A, W, U, V
> ; Solve A.X=B
> X=SVSOL(U, W, V, B)
>
> ; Check
> B2=A##X
> ind=where(total(abs(A),1,/pres) ne 0)
>
> if array_equal(B[ind],B2[ind]) then print,X

Well, w contains the singular values, the number of these that are non-
zero will be the rank:
idx = where(w ne 0, rank)
print, rank
2

Does anyone else read the Help??????

Report message to a moderator

[Message index]

		Re: Matrix rank By: d.poreh on Fri, 14 December 2007 09:26
		Re: Matrix rank By: d.poreh on Fri, 14 December 2007 09:19
		Re: Matrix rank By: Vince Hradil on Fri, 14 December 2007 09:17
		Re: Matrix rank By: David Fanning on Fri, 14 December 2007 08:35
		Re: Matrix rank By: Vince Hradil on Fri, 14 December 2007 08:28
		Re: Matrix rank By: David Fanning on Fri, 14 December 2007 07:57
		Re: Matrix rank By: Wox on Fri, 14 December 2007 07:44
		Re: Matrix rank By: Wox on Fri, 14 December 2007 07:42
		Re: Matrix rank By: d.poreh on Fri, 14 December 2007 07:41
		Re: Matrix rank By: Wox on Fri, 14 December 2007 07:25
		Re: Matrix rank By: Vince Hradil on Fri, 14 December 2007 06:35
		Re: Matrix rank By: Steve Eddins on Fri, 14 December 2007 10:06
		Re: Matrix rank By: Vince Hradil on Fri, 14 December 2007 09:49

Previous Topic:	Off Topic Computer Post
Next Topic:	Compiling error in Envi batch mode

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Fri Oct 10 15:01:50 PDT 2025

Total time taken to generate the page: 0.79321 seconds