BICGSTAB.h: Division by zero if 'r0.dot(v)' is zero => the iteration fails with 'not converged'.

Minimal Example

see https://www.godbolt.org/z/83515a3sT

What is the current bug behavior?

Iteration fails with 'not converged'.

What is the expected correct behavior?

Same result as a dense solver

Anything else that might help

A start vector usually helps to avoid the problem, but not reliably. I think it should be ensured that a 'divide by 0' does not occur. However, it is not clear to me how to avoid this in a meaningful way.