Trait ExactNewtonJointPsiWorkspace 

pub trait ExactNewtonJointPsiWorkspace: Send + Sync {
    // Required methods
    fn second_order_terms(
        &self,
        psi_i: usize,
        psi_j: usize,
    ) -> Result<Option<ExactNewtonJointPsiSecondOrderTerms>, String>;
    fn hessian_directional_derivative(
        &self,
        psi_index: usize,
        d_beta_flat: &Array1<f64>,
    ) -> Result<Option<DriftDerivResult>, String>;

    // Provided methods
    fn first_order_terms(
        &self,
        _: usize,
    ) -> Result<Option<ExactNewtonJointPsiTerms>, String> { ... }
    fn first_order_terms_all(
        &self,
    ) -> Result<Option<Vec<ExactNewtonJointPsiTerms>>, String> { ... }
    fn second_order_terms_contracted(
        &self,
        _: &[f64],
    ) -> Result<Option<ExactNewtonJointPsiSecondOrderContracted>, String> { ... }
}

Required Methods

fn second_order_terms( &self, psi_i: usize, psi_j: usize, ) -> Result<Option<ExactNewtonJointPsiSecondOrderTerms>, String>

fn hessian_directional_derivative( &self, psi_index: usize, d_beta_flat: &Array1<f64>, ) -> Result<Option<DriftDerivResult>, String>

Provided Methods

fn first_order_terms( &self, _: usize, ) -> Result<Option<ExactNewtonJointPsiTerms>, String>

fn first_order_terms_all( &self, ) -> Result<Option<Vec<ExactNewtonJointPsiTerms>>, String>

fn second_order_terms_contracted( &self, _: &[f64], ) -> Result<Option<ExactNewtonJointPsiSecondOrderContracted>, String>

Direction-contracted second-order ψ terms for the profiled θ-HVP (#740).

Given the ψ-block weights alpha_psi (length psi_dim, the ψ slice of one applied outer direction α), return the α-contraction of every (ψ_i, ψ_j) second-order term against the combined ψ-direction ψ(α) = Σ_j alpha_psi[j] · ψ_j, as ExactNewtonJointPsiSecondOrderContracted. A family that can stream its rows once over ψ(α) overrides this so the profiled outer-Hessian operator applies one combined-direction n-pass per matvec instead of the dense path’s K² per-pair Self::second_order_terms passes.

Default returns None: the profiled θ-HVP operator is then not built and the evaluator keeps the exact per-pair assembly (dense compute_outer_hessian / build_outer_hessian_operator). Overriding this method is purely a representation/cost choice — it must produce the exact same contraction the per-pair terms would, which the profiled_theta_hvp_outer_hessian_fd finite-difference cross-check guards.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors