Function check_coherence_or_reject 

pub fn check_coherence_or_reject(
    matrix: &dyn Matrix,
    threshold: Precision,
) -> Result<Precision>

Verify that a matrix’s coherence meets or exceeds the configured threshold; otherwise return SolverError::Incoherent.

If threshold <= 0.0 the gate is disabled — this is the default for SolverOptions, preserving wire compatibility with every existing caller. Setting threshold = 0.05 enables the gate.

Cost: one coherence_score call. Linear in the matrix’s nonzeros.