Enum Checkpoint 

pub enum Checkpoint {
    IterStart,
    AfterBarrierUpdate,
    AfterSearchDirection,
    AfterStep,
    StepRejected,
    PreRestoration,
    PostRestoration,
    Terminated,
}

Where in a solver’s loop a checkpoint fired.

The variants cover the NLP filter-IPM’s loop; other interior-point solvers fire the subset that applies to them (e.g. the convex IPM uses IterStart, AfterSearchDirection, AfterStep, and Terminated; it has no restoration phase or backtracking line search, so those variants simply never fire).

Variants

IterStart

Top of an outer iteration — before this iteration’s step is computed. The iterate, multipliers, and μ reflect the accepted point from the previous iteration.

AfterBarrierUpdate

After the barrier parameter μ was updated for this iteration (before the search direction is computed).

AfterSearchDirection

After the primal-dual Newton step was computed — the search direction δ, the applied regularization, and the KKT factorization are available.

AfterStep

After a step length was chosen and the trial point accepted — the step lengths α and the new iterate are in place.

StepRejected

The line search rejected this iteration’s step and the solver is about to fall into restoration (NLP filter-IPM only).

PreRestoration

Just before the algorithm switches into the restoration phase (NLP filter-IPM only).

PostRestoration

Just after the restoration phase returns (NLP filter-IPM only).

Terminated

The solve has finished: fired once before the solver returns, at the final iterate, carrying the outcome via DebugState::status. The DebugAction returned here is ignored — the solve is already over.

Implementations

impl Checkpoint

pub fn as_str(self) -> &'static str

The stable wire/CLI protocol name for this checkpoint. These strings are intentionally not the variant identifiers (AfterBarrierUpdate → "after_mu", PreRestoration → "pre_restoration_entry") — they’re the names the JSON protocol and stop-at use, so match on the variant, not the string.

pub fn is_sub_iteration(self) -> bool

Sub-iteration checkpoints (everything between IterStart and the next IterStart).

Trait Implementations

impl Clone for Checkpoint

fn clone(&self) -> Checkpoint

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Checkpoint

impl Debug for Checkpoint

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

Formats the value using the given formatter.

impl Eq for Checkpoint

impl PartialEq for Checkpoint

fn eq(&self, other: &Checkpoint) -> 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 StructuralPartialEq for Checkpoint