rtol
The relative convergence tolerance.
Declaration
var rtol: DoubleDiscussion
‖ b-Ax ‖₂ < rtol * ‖ b-Ax₀ ‖₂ + atol indicates convergence.
If rtol = 0, the operation uses the default value of sqrt(epsilon).
If it’s negative, the system treats rtol as 0.0 (it doesn’t use the default).