public inbox for gsl-discuss@sourceware.org
 help / color / mirror / Atom feed
* Vector cross product
@ 2003-08-11 13:57 Haisam K. Ido
  2003-08-12 10:55 ` Brian Gough
  0 siblings, 1 reply; 4+ messages in thread
From: Haisam K. Ido @ 2003-08-11 13:57 UTC (permalink / raw)
  To: gsl-discuss

I've searched GSL and can't find a function to take the cross product of two 
vectors.   Can someone help?

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Vector cross product
  2003-08-11 13:57 Vector cross product Haisam K. Ido
@ 2003-08-12 10:55 ` Brian Gough
  2003-08-12 15:20   ` Haisam K. Ido
  0 siblings, 1 reply; 4+ messages in thread
From: Brian Gough @ 2003-08-12 10:55 UTC (permalink / raw)
  To: Haisam K. Ido; +Cc: gsl-discuss

Haisam K. Ido writes:
 > I've searched GSL and can't find a function to take the cross
 > product of two vectors.  Can someone help?

There isn't one -- it's specific to 3 dimensions and can be calculated
in a few lines.

-- 
Brian Gough

Network Theory Ltd            
15 Royal Park                 
Bristol BS8 3AL               
United Kingdom                

Tel: +44 (0)117 3179309 
Fax: +44 (0)117 9048108              
Web: http://www.network-theory.co.uk/

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Vector cross product
  2003-08-12 10:55 ` Brian Gough
@ 2003-08-12 15:20   ` Haisam K. Ido
  2003-08-12 15:24     ` Adam Johansen
  0 siblings, 1 reply; 4+ messages in thread
From: Haisam K. Ido @ 2003-08-12 15:20 UTC (permalink / raw)
  To: gsl-discuss


Agreed that it's simple, but the dot product is even simpler and is included with 
GSL/BLAS.  Even a*A[][] is included (a is a scalar) which is even simpler than the 
dot product!

Brian Gough wrote:
> Haisam K. Ido writes:
>  > I've searched GSL and can't find a function to take the cross
>  > product of two vectors.  Can someone help?
> 
> There isn't one -- it's specific to 3 dimensions and can be calculated
> in a few lines.
> 

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Vector cross product
  2003-08-12 15:20   ` Haisam K. Ido
@ 2003-08-12 15:24     ` Adam Johansen
  0 siblings, 0 replies; 4+ messages in thread
From: Adam Johansen @ 2003-08-12 15:24 UTC (permalink / raw)
  To: GSL

Haisam K. Ido wrote:

>
> Agreed that it's simple, but the dot product is even simpler and is 
> included with GSL/BLAS.  Even a*A[][] is included (a is a scalar) 
> which is even simpler than the dot product!
>
I think the point which Brian was trying to make -- and I apologise in 
advance if I'm wrong -- is that a dot product is general and applies to 
vectors of any length as the sum of the pairwise products of the 
elements of those vectors. In contrast, the vector product you're 
referring to only exists when the vector is of length three. As such 
it's a specialised case and not worth including in the library.

Adam

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2003-08-12 15:24 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2003-08-11 13:57 Vector cross product Haisam K. Ido
2003-08-12 10:55 ` Brian Gough
2003-08-12 15:20   ` Haisam K. Ido
2003-08-12 15:24     ` Adam Johansen

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).