>> So after all I might just code the inversion via Gauss elimination >> myself in a way that can deal with fractions, shouldn't be that hard. > > I wouldn't do it that way. Let M be your matrix. Work out the LCM l of > the denominators, and multiply the matrix by that to make it an integer > matrix N = l M. Then work out the determinant d of that integer matrix. > Next, the big step: use Gaussian elimination to find a matrix A (the > `adjugate matrix') such that A N = d I. This should be doable entirely > using integer arithmetic, and I think without needing any divisions. > Finally, we have l A M = d I, so (l/d A) M = I and l/d A is the inverse > you seek. > > Does that make sense?
Absolutely! But there is nothing wrong with working out the inverse directly using fractions.Fraction arithmetic, I'd think. Cheers, Daniel -- Psss, psss, put it down! - http://www.cafepress.com/putitdown -- http://mail.python.org/mailman/listinfo/python-list
