Enum LanczosError 

#[non_exhaustive]
pub enum LanczosError {
    NonFinite {
        iters: usize,
        eigenvalue: f64,
        residual: f64,
    },
}

Errors from the native Lanczos solver.

This carries only genuine runtime failures the caller can recover from. Caller-side invariant violations (dim == 0, max_iter == 0, a non-finite or negative tol) and operator-contract violations (an LinearOp::apply returning a tensor of shape other than [dim]) remain panics — they are programmer errors, not recoverable conditions. Failing to reach the requested tol is likewise not an error: it is reported as LanczosResult::converged being false so the caller keeps the best Ritz pair.

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.

NonFinite

The computed eigenpair is not finite (NaN/Inf), typically because the operator emitted a non-finite vector or the 2-norm overflowed (see the overflow note on lanczos_smallest). A non-finite result must not flow on as a normal LanczosResult, where it would silently poison every downstream computation. The diagnostics are carried as f64 so the error type stays non-generic.

Fields

iters: usize

Lanczos iterations run before the non-finite result was detected.

eigenvalue: f64

Computed eigenvalue (lossily cast to f64).

residual: f64

True residual (lossily cast to f64).

Trait Implementations

impl Debug for LanczosError

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

Formats the value using the given formatter.

impl Display for LanczosError

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

Formats the value using the given formatter.

impl Error for LanczosError

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.

impl From<LanczosError> for DmrgHeffError

fn from(source: LanczosError) -> Self

Converts to this type from the input type.