This directory contains raw and checked LAPACK wrappers for configured CPU providers. It is the external-library boundary below dense linalg policy.

uni20_backend_lapack owns LAPACK discovery and transitive provider linkage. It remains available when Uni20's BLAS operation backend is disabled; a conventional LAPACK provider may still link a BLAS implementation internally.

lapack.hpp: checked wrappers that translate LAPACK INFO values into invariant failures, structured exceptions, or operation-specific status returns.
lapack_error.hpp: structured terminal LAPACK failure data.
lapack_error_presentation.hpp: terminal and plain-text presentation for structured LAPACK failures.
common.hpp: shared LAPACK backend helpers.
`reference/`: ordinary LAPACK provider declarations grouped by routine family.
`mplapack/`: MPLAPACK-backed declarations for supported extended-precision scalar types.

Notes

Keep pointer/leading-dimension interfaces and provider-specific overloads in this backend layer.
Shape validation, view materialization, and tensor allocation policy belong in higher linalg helpers.

Checked <tt>INFO</tt> Policy

Unchecked provider wrappers return LAPACK INFO verbatim. Checked wrappers use the following policy after Uni20 has selected a routine and constructed its arguments:

INFO < 0 means the provider rejected a wrapper-generated argument. This is a Uni20 lowering or provider-contract bug and unconditionally fails a CHECK, including when Python exception mode is active.
INFO > 0 means the provider ran but did not produce the requested result. The wrapper raises a structured LapackError containing the routine, INFO, and interpreted reason. trace::raise aborts with a diagnostic in native C++ mode and preserves LapackError as an exception in Python mode.
A positive value explicitly documented as a usable operation status remains a return value. For example, expert solve wrappers report reciprocal condition warnings as bool, and trsyl reports perturbation of close eigenvalues.

These terminal failures are not kernel declines. Once a backend calls LAPACK, the operands may have been overwritten and dispatch must not continue to a later backend.

Contents

Notes

Checked <tt>INFO</tt> Policy

Related Documentation