Mercurial > octave
diff libinterp/dldfcn/__eigs__.cc @ 27683:6604b41ca63f
Return only real eigenvalues from eigs() for symmetric matrices (bug #57196).
* __eigs__.cc (F__eigs__): Test complex matrices for symmettry (Hermitian). If
found, take the real() part of the result from ARPACK before returning the
values.
| author | Rik <rik@octave.org> |
|---|---|
| date | Wed, 13 Nov 2019 09:37:26 -0800 |
| parents | 041caa61ed34 |
| children | e557774a2604 |
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--- a/libinterp/dldfcn/__eigs__.cc Tue Nov 12 15:39:05 2019 +0100 +++ b/libinterp/dldfcn/__eigs__.cc Wed Nov 13 09:37:26 2019 -0800 @@ -231,8 +231,6 @@ else acm = (args(0).complex_matrix_value ()); a_is_complex = true; - symmetric = false; // ARPACK doesn't special case complex symmetric - sym_tested = true; } else { @@ -464,9 +462,19 @@ } if (nargout < 2) - retval(0) = eig_val; + { + if (symmetric) + retval(0) = real (eig_val); + else + retval(0) = eig_val; + } else - retval = ovl (eig_vec, ComplexDiagMatrix (eig_val), double (info)); + { + if (symmetric) + retval = ovl (eig_vec, DiagMatrix (real (eig_val)), double (info)); + else + retval = ovl (eig_vec, ComplexDiagMatrix (eig_val), double (info)); + } } else if (sigmai != 0.0) { @@ -502,9 +510,19 @@ } if (nargout < 2) - retval(0) = eig_val; + { + if (symmetric) + retval(0) = real (eig_val); + else + retval(0) = eig_val; + } else - retval = ovl (eig_vec, ComplexDiagMatrix (eig_val), double (info)); + { + if (symmetric) + retval = ovl (eig_vec, DiagMatrix (real (eig_val)), double (info)); + else + retval = ovl (eig_vec, ComplexDiagMatrix (eig_val), double (info)); + } } else {