Function log_gradient_resolution 

pub fn log_gradient_resolution() -> f64

ln √ε: the log of the relative resolution of a criterion gradient carried through an inverse whose conditioning is the strength ratio itself. Per direction the ρ-gradient is the effective degrees of freedom γ/(γ+λ) through (H+λS)⁻¹, whose condition in that direction is λ/γ once the penalty dominates; a quantity through an inverse of condition κ holds relative error εκ, and value and error cross at λ/γ = 1/√ε. Every derived ρ-domain edge (#2812) is this many e-folds from the spectrum.