Enum HessianMethod 

pub enum HessianMethod {
    DirectPsb,
    InverseBfgs,
    Bofill,
    Powell,
    BfgsPowellMix,
}

Hessian update method for geometry optimization.

Determines how the Hessian matrix (or its inverse) is stored and updated at each optimization step. The choice affects convergence behavior, especially near crossing points.

Variants

DirectPsb

Direct Hessian + PSB (Powell-Symmetric-Broyden) update. Stores the full Hessian H (Ha/Ų), solves H·dk = -g via LU. Recommended for MECP. Required for blend optimizer.

InverseBfgs

Inverse H⁻¹ + BFGS update (Fortran-style). Stores H⁻¹ (Ų/Ha), computes step as H⁻¹·g via multiply. Incompatible with blend optimizer.

Bofill

Bofill weighted update for saddle-point-like crossings. Direct Hessian. Blends Powell and Murtagh-Sargent.

Powell

Powell symmetric rank-one (SR1) update. Direct Hessian.

BfgsPowellMix

Adaptive BFGS/Powell blend with Bofill weighting. Direct Hessian.

Implementations

impl HessianMethod

pub fn is_direct(&self) -> bool

Returns true if this method stores a direct Hessian H (not inverse).

Direct Hessian methods solve linear systems H·e = F to compute error vectors. They are required for the blend optimizer.

pub fn is_inverse(&self) -> bool

Returns true if this method stores an inverse Hessian H⁻¹.

Trait Implementations

impl Clone for HessianMethod

fn clone(&self) -> HessianMethod

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for HessianMethod

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for HessianMethod

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for HessianMethod

fn eq(&self, other: &HessianMethod) -> 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 Serialize for HessianMethod

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for HessianMethod