Finding matrix modulo n inverse in octave

Question

I have to find the modulo 29 inverse of a 30x30 matrix. I've tried using the det^-1 * adjoint, but I can't seem to find the det^-1 because the det is something like -7.4269e+16. Any ideas?

Answer 1

As in the computation of modular powers, it is advisable and even essential for an efficient implementation to reduce the intermediate results modulo 29.

Thus if there is no dedicated algorithm for this function or modular integer number type usable in the standard function calls in matlab, you will have to implement a variant of the Gauß-algorithm on your own.

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Using google one of course finds solutions for everything: modsolve.m