Report factor value bytes and preserve overflow-safe reduction limits

crates/solver/src/heat.rs

@@ -303,9 +303,7 @@ fn prescribed(model: &Model, resolved: &Resolved, mesh: &HeatMesh, step: &Step)
 
 fn factor(a: &Csr, limits: &Limits, mesh: &HeatMesh, eqs: &Reduction) -> Result<Factor> {
     Factor::new(&UpperColumns::from_symmetric(a), limits.max_factor_entries).map_err(|e| match e {
-        FactorError::TooLarge { entries, limit } => {
-            Error::Limit(format!("the factorization needs {entries} entries; the limit is {limit} (refine less or raise the limit)"))
-        }
+        FactorError::TooLarge { entries, limit } => Error::factor_limit(entries, limit),
         FactorError::OutOfMemory { entries } => Error::Limit(format!("not enough memory for the factorization ({entries} entries)")),
         FactorError::Internal(what) => Error::Internal(what),
         FactorError::Cancelled => Error::Model(fieldcraft_model::Error::Cancelled),