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| author | julie <julielangou@users.noreply.github.com> | 2011-11-01 22:02:31 +0000 |
|---|---|---|
| committer | julie <julielangou@users.noreply.github.com> | 2011-11-01 22:02:31 +0000 |
| commit | d5c30c90bdecf38da1064e2ed52583634573e741 (patch) | |
| tree | 480fc5ff31ee14b83116b6428aad79ea6e89362d /SRC/zheevx.f | |
| parent | 04670a68760fa27333f8bcef8172f71adc6880ef (diff) | |
Never say never...
Diffstat (limited to 'SRC/zheevx.f')
| -rw-r--r-- | SRC/zheevx.f | 15 |
1 files changed, 5 insertions, 10 deletions
diff --git a/SRC/zheevx.f b/SRC/zheevx.f index 3b96e40f..02bac469 100644 --- a/SRC/zheevx.f +++ b/SRC/zheevx.f @@ -131,24 +131,20 @@ *> An approximate eigenvalue is accepted as converged *> when it is determined to lie in an interval [a,b] *> of width less than or equal to -*> \endverbatim -*> \verbatim +*> *> ABSTOL + EPS * max( |a|,|b| ) , -*> \endverbatim -*> \verbatim +*> *> where EPS is the machine precision. If ABSTOL is less than *> or equal to zero, then EPS*|T| will be used in its place, *> where |T| is the 1-norm of the tridiagonal matrix obtained *> by reducing A to tridiagonal form. -*> \endverbatim -*> \verbatim +*> *> Eigenvalues will be computed most accurately when ABSTOL is *> set to twice the underflow threshold 2*DLAMCH('S'), not zero. *> If this routine returns with INFO>0, indicating that some *> eigenvectors did not converge, try setting ABSTOL to *> 2*DLAMCH('S'). -*> \endverbatim -*> \verbatim +*> *> See "Computing Small Singular Values of Bidiagonal Matrices *> with Guaranteed High Relative Accuracy," by Demmel and *> Kahan, LAPACK Working Note #3. @@ -205,8 +201,7 @@ *> For optimal efficiency, LWORK >= (NB+1)*N, *> where NB is the max of the blocksize for ZHETRD and for *> ZUNMTR as returned by ILAENV. -*> \endverbatim -*> \verbatim +*> *> If LWORK = -1, then a workspace query is assumed; the routine *> only calculates the optimal size of the WORK array, returns *> this value as the first entry of the WORK array, and no error |