Enum HessianMaterialization 

pub enum HessianMaterialization {
    Unavailable,
    RepeatedHvp,
    BatchedHvp,
    Explicit,
}

How (and whether) a HessianOperator can produce a dense materialized Hessian. Reported by HessianOperator::materialization() so a trust-region or ARC solver can decide between calling materialize_dense once and falling back to repeated Hessian-vector products through apply_into.

Variants

Unavailable

Operator cannot produce a dense matrix; only Hv products are available. Solvers that require a dense Hessian must error or fall back to a matrix-free step (Steihaug-Toint, etc.).

RepeatedHvp

Materialization is possible but expensive: it costs one apply_into per column. Solvers should prefer matrix-free iterations unless the dimension is small.

BatchedHvp

Materialization can use a batched/multi-RHS path that is faster than n separate apply_into calls (e.g. tangent propagation across all basis vectors at once).

Explicit

The operator already holds a dense Hessian (or can produce one without extra Hv probes). materialize_dense() is essentially free.

Implementations

impl HessianMaterialization

pub fn is_available(self) -> bool

True when materialize_dense is expected to succeed and produce a usable result without significant additional work beyond what any other access would cost.

Trait Implementations

impl Clone for HessianMaterialization

fn clone(&self) -> HessianMaterialization

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for HessianMaterialization

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for HessianMaterialization

fn eq(&self, other: &HessianMaterialization) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for HessianMaterialization

impl Eq for HessianMaterialization

impl StructuralPartialEq for HessianMaterialization