Enum SolverError 

pub enum SolverError {
    Infeasible,
    Unbounded,
    NumericalDifficulty {
        message: String,
    },
    TimeLimitExceeded {
        elapsed_seconds: f64,
    },
    IterationLimit {
        iterations: u64,
    },
    InternalError {
        message: String,
        error_code: Option<i32>,
    },
    Unsupported(&'static str),
    BasisInconsistent {
        num_row: i64,
        total_basic: i64,
        col_basic: i64,
        row_basic: i64,
    },
    BasisRowCountMismatch {
        lp_rows: usize,
        basis_rows: usize,
    },
}

Terminal LP solve error returned after all retry attempts are exhausted.

The calling algorithm uses the variant to determine its response: hard stop (Infeasible, Unbounded, InternalError) or terminate with a diagnostic error (NumericalDifficulty, TimeLimitExceeded, IterationLimit).

The six variants correspond to the error categories defined in Solver Abstraction SS6. Solver-internal errors (e.g., factorization failures) are resolved by retry logic before reaching this level.

Variants

Infeasible

The LP has no feasible solution.

Indicates a data error (inconsistent bounds or constraints) or a modeling error. The calling algorithm should perform a hard stop.

Unbounded

The LP objective is unbounded below.

Indicates a modeling error (missing bounds, incorrect objective sign). The calling algorithm should perform a hard stop.

NumericalDifficulty

Solver encountered numerical difficulties that persisted through all retry attempts.

The calling algorithm should log the error and perform a hard stop.

Fields

message: String

Human-readable description of the numerical issue from the solver.

TimeLimitExceeded

Per-solve wall-clock time budget exhausted.

Fields

elapsed_seconds: f64

Elapsed wall-clock time in seconds at the point of termination.

IterationLimit

Solver simplex iteration limit reached.

Fields

iterations: u64

Number of simplex iterations performed before the limit was hit.

InternalError

Unrecoverable solver-internal failure.

Covers FFI panics, memory allocation failures within the solver, corrupted internal state, or any error not classifiable into the above categories. The calling algorithm should log the error and perform a hard stop.

Fields

message: String

Human-readable error description.

error_code: Option<i32>

Solver-specific error code, if available.

Unsupported(&'static str)

The backend does not implement the requested operation.

The caller should fall back to an alternate code path (e.g., reset + load_model).

BasisInconsistent

The offered basis was rejected by the solver because the total number of basic variables did not match the row count.

Indicates that the reconstructed basis violates the fundamental LP basis consistency invariant (col_basic + row_basic == num_row). The calling algorithm should perform a hard stop; this is not a recoverable solver-internal condition.

Fields

num_row: i64

The LP row count at the point of rejection.

total_basic: i64

The total basic-variable count in the offered basis (col_basic + row_basic).

col_basic: i64

Number of basic columns in the offered basis.

row_basic: i64

Number of basic rows in the offered basis.

BasisRowCountMismatch

The offered warm-start basis has fewer row entries than the loaded LP has rows. The basis predates an add_rows growth and cannot be padded soundly (a BASIC pad is wrong for inequality-row slacks), so it is rejected; the caller should fall back to a cold solve.

Fields

lp_rows: usize

The LP row count at the point of rejection.

basis_rows: usize

The row-entry count in the offered basis.

Trait Implementations

impl Debug for SolverError

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

Formats the value using the given formatter.

impl Display for SolverError

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

Formats the value using the given formatter.

impl Error for SolverError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.