[comp.sources.wanted] C matrix inverter wanted

dc@cs.qmw.ac.uk (Daniel Cohen) (05/22/91)

A friend of mine without net access has asked me to post this
request for C code to invert matrices. He has not fixed on any
particular format for matrices so this is not a factor.

Please email your code to me ( unless it's megabytes! )

Thanks

--
Daniel Cohen              Department of Computer Science 
Email: dc@dcs.qmw.ac.uk   Queen Mary and Westfield College
Tel: +44 71 975 5249/4/5  Mile End Road, London E1 4NS, UK
Fax: +44 81 980 6533      *** Glory, Glory, Hallelujah ***

dodson@convex.COM (Dave Dodson) (05/23/91)

In article <dc.674925732@gin> dc@cs.qmw.ac.uk (Daniel Cohen) writes:
>A friend of mine without net access has asked me to post this
>request for C code to invert matrices. He has not fixed on any
>particular format for matrices so this is not a factor.
>
>Please email your code to me ( unless it's megabytes! )

I suggest you use Numerical Recipes in C.  HOWEVER, IT IS ALMOST NEVER
NECESSARY OR DESIRABLE TO INVERT A MATRIX.  There are very few instances
where you actually need the elements of the inverse.  For example, you
wouldn't solve the equation 3*x = 6 by computing 3^(-1) = 0.333...
and then multiplying by 6.  Why solve linear equations that way?

Write back if you have more questions.

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Dave Dodson		                             dodson@convex.COM
Convex Computer Corporation      Richardson, Texas      (214) 497-4234