Jeroen Demeyer on Mon, 11 May 2009 10:24:38 +0200

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Re: Another problem with matrix inversion

Lorenz Minder wrote:
So while A has an inverse in this case, it is not found.  The workaround
using chinese remaindering works if the factorization is known, so this
is going to be a problem if the modulus is an RSA modulus, for example.
It would be better to try to run the algorithm as is, and as soon as a
nonzero non-invertible remainder is found, to split into two instances
with the now known partial factorization and continue.

This brings up another question regarding GP: is it possible to trap "impossible inverse modulo" errors and actually recover the element which caused the impossible inverse? I think it would be nice to have that functionality in GP, but I don't really know what would be the correct way to do it.