Enum Error 

#[non_exhaustive]
pub enum Error {
    InvalidParam(&'static str),
    AupdFailed(i32),
    EupdFailed(i32),
    UnexpectedIdo(i32),
    MaxIterReached {
        iters: usize,
        nconv: usize,
        n_matvec: usize,
    },
}

Errors raised by the safe ARPACK wrappers.

info codes are passed through verbatim from the underlying *aupd_c and *eupd_c routines so the caller can interpret them against the ARPACK Users’ Guide. Negative values indicate misuse or numerical failure; positive values other than 1 indicate non-recoverable convergence conditions (e.g. info = 3 from aupd means no shifts could be applied — try increasing ncv).

info = 1 from *aupd_c (max_iter reached before all nev Ritz pairs converged) is mapped to Error::MaxIterReached, which preserves the iparam diagnostic counters so the caller can decide whether to retry with a larger budget. For the single-eigenpair drivers (nev = 1) currently exposed, info = 1 always means nconv = 0 and no usable Ritz pair was extracted.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

InvalidParam(&'static str)

A wrapper-side parameter check failed before any FFI call.

AupdFailed(i32)

The reverse-communication driver (*aupd_c) returned a non-zero info code that is not separately modelled.

EupdFailed(i32)

The eigenvector-extraction routine (*eupd_c) returned a non-zero info code.

UnexpectedIdo(i32)

*aupd_c requested an ido value the wrapper does not support (currently ido = 2, which only occurs for generalized eigenproblems with bmat = 'G').

MaxIterReached

*aupd_c returned info = 1: the iteration hit max_iter before the requested nev Ritz pairs converged. The iparam writeback counters are preserved so the caller can retry with a larger max_iter or report partial progress.

Fields

iters: usize

iparam[2] writeback — restart iterations performed (equals Options::max_iter when the cap was hit).

nconv: usize

iparam[4] writeback — converged Ritz value count. For the single-eigenpair drivers this is always 0 when this variant is returned.

n_matvec: usize

iparam[8] writeback — operator applications performed.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

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.