* unimodular basis, is updated to reflect the reduced basis.
* The first tab->n_zero rows of the basis (ignoring the constant row)
* are assumed to correspond to equalities and are left untouched.
* unimodular basis, is updated to reflect the reduced basis.
* The first tab->n_zero rows of the basis (ignoring the constant row)
* are assumed to correspond to equalities and are left untouched.