matrix inversion
Author Message
matrix inversion

: Hallo!!

: For all who need a C-programm for matrix inversion.
: The program based at the Gauss-Jordan algorithm.
: The algorithm is able to solve every n x n - matrix.
: Good Luck!

: /* Calculatie the inverse of an n x n - matrix */

NOTE: This implementation of Gauss-Jordan elimination will work,
but to be numerically stable requires pivoting. Instead of choosing
dummy = a[k][k] every time, you must look down the k_th column and find
the largest element in it; then switch the k_th row of a and b with that
row, and proceed as normal. If you don't do this it's easy to cook up a
matrix whose computed inverse is completely wrong.

Also, for production solution of inverses you should use an LU
factorization; essentially every time you compute a dummy you save it
somewhere. For a 10x10 matrix the inverse calculated this way can be
almost 10 times faster.

Also, please post Basic code to a Basic newsgroup.

Also, that's it.
jasonp

Thu, 06 Apr 2000 03:00:00 GMT
matrix inversion

JSP>: Hallo!!
JSP>: For all who need a C-programm for matrix inversion.

Ok, but where is the program? Only the text below showed up here.

JSP>: The program based at the Gauss-Jordan algorithm.
JSP>: The algorithm is able to solve every n x n - matrix.
JSP>: Good Luck!
JSP>: /* Calculatie the inverse of an n x n - matrix */
JSP>NOTE: This implementation of Gauss-Jordan elimination will work,
JSP>but to be numerically stable requires pivoting. Instead of choosing
JSP>dummy = a[k][k] every time, you must look down the k_th column and find
JSP>the largest element in it; then switch the k_th row of a and b with that
JSP>row, and proceed as normal. If you don't do this it's easy to cook up a
JSP>matrix whose computed inverse is completely wrong.
JSP>Also, for production solution of inverses you should use an LU
JSP>factorization; essentially every time you compute a dummy you save it
JSP>somewhere. For a 10x10 matrix the inverse calculated this way can be
JSP>almost 10 times faster.
JSP>Also, please post Basic code to a Basic newsgroup.

I thought this was a BASIC newsgroup??? What do you mean???

JSP>Also, that's it.
JSP>jasonp

* OLX 2.1 TD * Nuke the gay whales for Christ!

Fri, 14 Apr 2000 03:00:00 GMT

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