--- rpl/lapack/lapack/zlarrv.f 2014/01/27 09:28:39 1.15 +++ rpl/lapack/lapack/zlarrv.f 2023/08/07 08:39:31 1.24 @@ -2,18 +2,18 @@ * * =========== DOCUMENTATION =========== * -* Online html documentation available at -* http://www.netlib.org/lapack/explore-html/ +* Online html documentation available at +* http://www.netlib.org/lapack/explore-html/ * *> \htmlonly -*> Download ZLARRV + dependencies -*> -*> [TGZ] -*> -*> [ZIP] -*> +*> Download ZLARRV + dependencies +*> +*> [TGZ] +*> +*> [ZIP] +*> *> [TXT] -*> \endhtmlonly +*> \endhtmlonly * * Definition: * =========== @@ -23,7 +23,7 @@ * RTOL1, RTOL2, W, WERR, WGAP, * IBLOCK, INDEXW, GERS, Z, LDZ, ISUPPZ, * WORK, IWORK, INFO ) -* +* * .. Scalar Arguments .. * INTEGER DOL, DOU, INFO, LDZ, M, N * DOUBLE PRECISION MINRGP, PIVMIN, RTOL1, RTOL2, VL, VU @@ -35,7 +35,7 @@ * $ WGAP( * ), WORK( * ) * COMPLEX*16 Z( LDZ, * ) * .. -* +* * *> \par Purpose: * ============= @@ -59,12 +59,15 @@ *> \param[in] VL *> \verbatim *> VL is DOUBLE PRECISION +*> Lower bound of the interval that contains the desired +*> eigenvalues. VL < VU. Needed to compute gaps on the left or right +*> end of the extremal eigenvalues in the desired RANGE. *> \endverbatim *> *> \param[in] VU *> \verbatim *> VU is DOUBLE PRECISION -*> Lower and upper bounds of the interval that contains the desired +*> Upper bound of the interval that contains the desired *> eigenvalues. VL < VU. Needed to compute gaps on the left or right *> end of the extremal eigenvalues in the desired RANGE. *> \endverbatim @@ -81,7 +84,7 @@ *> L is DOUBLE PRECISION array, dimension (N) *> On entry, the (N-1) subdiagonal elements of the unit *> bidiagonal matrix L are in elements 1 to N-1 of L -*> (if the matrix is not splitted.) At the end of each block +*> (if the matrix is not split.) At the end of each block *> is stored the corresponding shift as given by DLARRE. *> On exit, L is overwritten. *> \endverbatim @@ -140,7 +143,7 @@ *> RTOL2 is DOUBLE PRECISION *> Parameters for bisection. *> An interval [LEFT,RIGHT] has converged if -*> RIGHT-LEFT.LT.MAX( RTOL1*GAP, RTOL2*MAX(|LEFT|,|RIGHT|) ) +*> RIGHT-LEFT < MAX( RTOL1*GAP, RTOL2*MAX(|LEFT|,|RIGHT|) ) *> \endverbatim *> *> \param[in,out] W @@ -236,7 +239,7 @@ *> INFO is INTEGER *> = 0: successful exit *> -*> > 0: A problem occured in ZLARRV. +*> > 0: A problem occurred in ZLARRV. *> < 0: One of the called subroutines signaled an internal problem. *> Needs inspection of the corresponding parameter IINFO *> for further information. @@ -258,12 +261,10 @@ * Authors: * ======== * -*> \author Univ. of Tennessee -*> \author Univ. of California Berkeley -*> \author Univ. of Colorado Denver -*> \author NAG Ltd. -* -*> \date September 2012 +*> \author Univ. of Tennessee +*> \author Univ. of California Berkeley +*> \author Univ. of Colorado Denver +*> \author NAG Ltd. * *> \ingroup complex16OTHERauxiliary * @@ -283,10 +284,9 @@ $ IBLOCK, INDEXW, GERS, Z, LDZ, ISUPPZ, $ WORK, IWORK, INFO ) * -* -- LAPACK auxiliary routine (version 3.4.2) -- +* -- LAPACK auxiliary routine -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- -* September 2012 * * .. Scalar Arguments .. INTEGER DOL, DOU, INFO, LDZ, M, N @@ -344,6 +344,14 @@ * .. Executable Statements .. * .. + INFO = 0 +* +* Quick return if possible +* + IF( (N.LE.0).OR.(M.LE.0) ) THEN + RETURN + END IF +* * The first N entries of WORK are reserved for the eigenvalues INDLD = N+1 INDLLD= 2*N+1