MathGroup Archive 2000

[Date Index] [Thread Index] [Author Index]

Search the Archive

Speeding up Inverting matrices.


I wish to solve the matrix equation Ax = b for x where A is a 24 x 24
matrix and x and b are column matrices. Most of the values in the matrix
are numbers (and many are equal to zero), but one remains unevaluated
i.e element [1,10] may be 160 + d, where d is unevaluated. Currently
we're using the command:

x = {Inverse [A]. b}

this works fine for the smaller matrices we use (8 x 8 and 16 x 16) but
the calculation has now be runing for over 2 days (the smaller matrices
may take many minutes if not seconds). The program is running on a PII
350MHz with 64Mb of RAM. Does anyone have any ideas about how to
optimise our calculation?

Ultimately I want to extract arbitary elements of x and plot them
against the unevaluated element.

Thanks for any help!

David

--
***************************************
David McGloin
Dept. of Physics
Univ. of St. Andrews
dm11 at st-and.ac.uk




  • Prev by Date: Re: Mathematica 4
  • Next by Date: Re: list manipulation, mean value
  • Previous by thread: Mathematica Training
  • Next by thread: Re: Speeding up Inverting matrices.