Struct NegativeCurvature 

pub struct NegativeCurvature {
    pub delta: IteratesVector,
    pub curvature: Number,
}

A direction of negative curvature at the current iterate, as returned by PdFullSpaceSolver::negative_curvature_direction (gh #797).

Fields

delta: IteratesVector

The direction. Only the x and s blocks are populated — every dual block is zero — and the primal part has unit infinity-norm, so a step length multiplying it is in the iterate’s own units.

curvature: Number

The measured dᵀ(W + Σ)d for Self::delta. Strictly negative whenever a value is returned: it is what makes the direction one the barrier objective decreases along to second order, and the caller sizes its sufficient-decrease test from it.