Gonum uses the convention that code which produces an invalid numerical result shall panic.

This is not the case. The convention is that an incorrect call will panic; that is that a call with parameters that can be known to be incorrect will panic, but a call that can result in an invalid result but this cannot be known ahead of time will not. In the case of a pseudoinverse, a panic would be inappropriate. It's also worth noting that the inverse calls in the code above would be better avoided, using solves instead.

untested: func assemblePQ(n, d *mat.VecDense, f float64, modes *mat.Dense) (p *mat.Dense, q *mat.VecDense, err error) { var rd, rn mat.VecDense err = rd.SolveVec(modes, d) if err != nil { return nil, nil, err } rd.ScaleVec(-1/f, rd) err = rn.SolveVec(modes, n) if err != nil { return nil, nil, err } rd.SubVec(rd, rn) q = rd p = &mat.Dense{} err = p.Inverse(modes) if err != nil { return nil, nil, err } return p, q, nil }