Ok, if it's just a 3x3, it probably won't make much difference in terms of computation time. Might be worth trying the tridiagonal solver from gsl if you find the existing method too slow.
AV
Hi again:
> Well, it depends on the format of the matrix. If it can be arranged into a
> tridiagonal form, then it can be inverted much faster using [1].
In my case is a bidimensional array:
double* A[3][3]
double* B[3]
Regards.