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diff --git a/SRC/zhbevd_2stage.f b/SRC/zhbevd_2stage.f new file mode 100644 index 00000000..e4daae74 --- /dev/null +++ b/SRC/zhbevd_2stage.f @@ -0,0 +1,458 @@ +*> \brief <b> ZHBEVD_2STAGE computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices</b> +* +* @precisions fortran z -> s d c +* +* =========== DOCUMENTATION =========== +* +* Online html documentation available at +* http://www.netlib.org/lapack/explore-html/ +* +*> \htmlonly +*> Download ZHBEVD_2STAGE + dependencies +*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zhbevd_2stage.f"> +*> [TGZ]</a> +*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zhbevd_2stage.f"> +*> [ZIP]</a> +*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zhbevd_2stage.f"> +*> [TXT]</a> +*> \endhtmlonly +* +* Definition: +* =========== +* +* SUBROUTINE ZHBEVD_2STAGE( JOBZ, UPLO, N, KD, AB, LDAB, W, Z, LDZ, +* WORK, LWORK, RWORK, LRWORK, IWORK, +* LIWORK, INFO ) +* +* IMPLICIT NONE +* +* .. Scalar Arguments .. +* CHARACTER JOBZ, UPLO +* INTEGER INFO, KD, LDAB, LDZ, LIWORK, LRWORK, LWORK, N +* .. +* .. Array Arguments .. +* INTEGER IWORK( * ) +* DOUBLE PRECISION RWORK( * ), W( * ) +* COMPLEX*16 AB( LDAB, * ), WORK( * ), Z( LDZ, * ) +* .. +* +* +*> \par Purpose: +* ============= +*> +*> \verbatim +*> +*> ZHBEVD_2STAGE computes all the eigenvalues and, optionally, eigenvectors of +*> a complex Hermitian band matrix A using the 2stage technique for +*> the reduction to tridiagonal. If eigenvectors are desired, it +*> uses a divide and conquer algorithm. +*> +*> The divide and conquer algorithm makes very mild assumptions about +*> floating point arithmetic. It will work on machines with a guard +*> digit in add/subtract, or on those binary machines without guard +*> digits which subtract like the Cray X-MP, Cray Y-MP, Cray C-90, or +*> Cray-2. It could conceivably fail on hexadecimal or decimal machines +*> without guard digits, but we know of none. +*> \endverbatim +* +* Arguments: +* ========== +* +*> \param[in] JOBZ +*> \verbatim +*> JOBZ is CHARACTER*1 +*> = 'N': Compute eigenvalues only; +*> = 'V': Compute eigenvalues and eigenvectors. +*> Not available in this release. +*> \endverbatim +*> +*> \param[in] UPLO +*> \verbatim +*> UPLO is CHARACTER*1 +*> = 'U': Upper triangle of A is stored; +*> = 'L': Lower triangle of A is stored. +*> \endverbatim +*> +*> \param[in] N +*> \verbatim +*> N is INTEGER +*> The order of the matrix A. N >= 0. +*> \endverbatim +*> +*> \param[in] KD +*> \verbatim +*> KD is INTEGER +*> The number of superdiagonals of the matrix A if UPLO = 'U', +*> or the number of subdiagonals if UPLO = 'L'. KD >= 0. +*> \endverbatim +*> +*> \param[in,out] AB +*> \verbatim +*> AB is COMPLEX*16 array, dimension (LDAB, N) +*> On entry, the upper or lower triangle of the Hermitian band +*> matrix A, stored in the first KD+1 rows of the array. The +*> j-th column of A is stored in the j-th column of the array AB +*> as follows: +*> if UPLO = 'U', AB(kd+1+i-j,j) = A(i,j) for max(1,j-kd)<=i<=j; +*> if UPLO = 'L', AB(1+i-j,j) = A(i,j) for j<=i<=min(n,j+kd). +*> +*> On exit, AB is overwritten by values generated during the +*> reduction to tridiagonal form. If UPLO = 'U', the first +*> superdiagonal and the diagonal of the tridiagonal matrix T +*> are returned in rows KD and KD+1 of AB, and if UPLO = 'L', +*> the diagonal and first subdiagonal of T are returned in the +*> first two rows of AB. +*> \endverbatim +*> +*> \param[in] LDAB +*> \verbatim +*> LDAB is INTEGER +*> The leading dimension of the array AB. LDAB >= KD + 1. +*> \endverbatim +*> +*> \param[out] W +*> \verbatim +*> W is DOUBLE PRECISION array, dimension (N) +*> If INFO = 0, the eigenvalues in ascending order. +*> \endverbatim +*> +*> \param[out] Z +*> \verbatim +*> Z is COMPLEX*16 array, dimension (LDZ, N) +*> If JOBZ = 'V', then if INFO = 0, Z contains the orthonormal +*> eigenvectors of the matrix A, with the i-th column of Z +*> holding the eigenvector associated with W(i). +*> If JOBZ = 'N', then Z is not referenced. +*> \endverbatim +*> +*> \param[in] LDZ +*> \verbatim +*> LDZ is INTEGER +*> The leading dimension of the array Z. LDZ >= 1, and if +*> JOBZ = 'V', LDZ >= max(1,N). +*> \endverbatim +*> +*> \param[out] WORK +*> \verbatim +*> WORK is COMPLEX*16 array, dimension (MAX(1,LWORK)) +*> On exit, if INFO = 0, WORK(1) returns the optimal LWORK. +*> \endverbatim +*> +*> \param[in] LWORK +*> \verbatim +*> LWORK is INTEGER +*> The length of the array WORK. LWORK >= 1, when N <= 1; +*> otherwise +*> If JOBZ = 'N' and N > 1, LWORK must be queried. +*> LWORK = MAX(1, dimension) where +*> dimension = (2KD+1)*N + KD*NTHREADS +*> where KD is the size of the band. +*> NTHREADS is the number of threads used when +*> openMP compilation is enabled, otherwise =1. +*> If JOBZ = 'V' and N > 1, LWORK must be queried. Not yet available. +*> +*> If LWORK = -1, then a workspace query is assumed; the routine +*> only calculates the optimal sizes of the WORK, RWORK and +*> IWORK arrays, returns these values as the first entries of +*> the WORK, RWORK and IWORK arrays, and no error message +*> related to LWORK or LRWORK or LIWORK is issued by XERBLA. +*> \endverbatim +*> +*> \param[out] RWORK +*> \verbatim +*> RWORK is DOUBLE PRECISION array, +*> dimension (LRWORK) +*> On exit, if INFO = 0, RWORK(1) returns the optimal LRWORK. +*> \endverbatim +*> +*> \param[in] LRWORK +*> \verbatim +*> LRWORK is INTEGER +*> The dimension of array RWORK. +*> If N <= 1, LRWORK must be at least 1. +*> If JOBZ = 'N' and N > 1, LRWORK must be at least N. +*> If JOBZ = 'V' and N > 1, LRWORK must be at least +*> 1 + 5*N + 2*N**2. +*> +*> If LRWORK = -1, then a workspace query is assumed; the +*> routine only calculates the optimal sizes of the WORK, RWORK +*> and IWORK arrays, returns these values as the first entries +*> of the WORK, RWORK and IWORK arrays, and no error message +*> related to LWORK or LRWORK or LIWORK is issued by XERBLA. +*> \endverbatim +*> +*> \param[out] IWORK +*> \verbatim +*> IWORK is INTEGER array, dimension (MAX(1,LIWORK)) +*> On exit, if INFO = 0, IWORK(1) returns the optimal LIWORK. +*> \endverbatim +*> +*> \param[in] LIWORK +*> \verbatim +*> LIWORK is INTEGER +*> The dimension of array IWORK. +*> If JOBZ = 'N' or N <= 1, LIWORK must be at least 1. +*> If JOBZ = 'V' and N > 1, LIWORK must be at least 3 + 5*N . +*> +*> If LIWORK = -1, then a workspace query is assumed; the +*> routine only calculates the optimal sizes of the WORK, RWORK +*> and IWORK arrays, returns these values as the first entries +*> of the WORK, RWORK and IWORK arrays, and no error message +*> related to LWORK or LRWORK or LIWORK is issued by XERBLA. +*> \endverbatim +*> +*> \param[out] INFO +*> \verbatim +*> INFO is INTEGER +*> = 0: successful exit. +*> < 0: if INFO = -i, the i-th argument had an illegal value. +*> > 0: if INFO = i, the algorithm failed to converge; i +*> off-diagonal elements of an intermediate tridiagonal +*> form did not converge to zero. +*> \endverbatim +* +* Authors: +* ======== +* +*> \author Univ. of Tennessee +*> \author Univ. of California Berkeley +*> \author Univ. of Colorado Denver +*> \author NAG Ltd. +* +*> \date November 2016 +* +*> \ingroup complex16OTHEReigen +* +*> \par Further Details: +* ===================== +*> +*> \verbatim +*> +*> All details about the 2stage techniques are available in: +*> +*> Azzam Haidar, Hatem Ltaief, and Jack Dongarra. +*> Parallel reduction to condensed forms for symmetric eigenvalue problems +*> using aggregated fine-grained and memory-aware kernels. In Proceedings +*> of 2011 International Conference for High Performance Computing, +*> Networking, Storage and Analysis (SC '11), New York, NY, USA, +*> Article 8 , 11 pages. +*> http://doi.acm.org/10.1145/2063384.2063394 +*> +*> A. Haidar, J. Kurzak, P. Luszczek, 2013. +*> An improved parallel singular value algorithm and its implementation +*> for multicore hardware, In Proceedings of 2013 International Conference +*> for High Performance Computing, Networking, Storage and Analysis (SC '13). +*> Denver, Colorado, USA, 2013. +*> Article 90, 12 pages. +*> http://doi.acm.org/10.1145/2503210.2503292 +*> +*> A. Haidar, R. Solca, S. Tomov, T. Schulthess and J. Dongarra. +*> A novel hybrid CPU-GPU generalized eigensolver for electronic structure +*> calculations based on fine-grained memory aware tasks. +*> International Journal of High Performance Computing Applications. +*> Volume 28 Issue 2, Pages 196-209, May 2014. +*> http://hpc.sagepub.com/content/28/2/196 +*> +*> \endverbatim +* +* ===================================================================== + SUBROUTINE ZHBEVD_2STAGE( JOBZ, UPLO, N, KD, AB, LDAB, W, Z, LDZ, + $ WORK, LWORK, RWORK, LRWORK, IWORK, + $ LIWORK, INFO ) +* + IMPLICIT NONE +* +* -- LAPACK driver routine (version 3.6.0) -- +* -- LAPACK is a software package provided by Univ. of Tennessee, -- +* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- +* November 2016 +* +* .. Scalar Arguments .. + CHARACTER JOBZ, UPLO + INTEGER INFO, KD, LDAB, LDZ, LIWORK, LRWORK, LWORK, N +* .. +* .. Array Arguments .. + INTEGER IWORK( * ) + DOUBLE PRECISION RWORK( * ), W( * ) + COMPLEX*16 AB( LDAB, * ), WORK( * ), Z( LDZ, * ) +* .. +* +* ===================================================================== +* +* .. Parameters .. + DOUBLE PRECISION ZERO, ONE + PARAMETER ( ZERO = 0.0D0, ONE = 1.0D0 ) + COMPLEX*16 CZERO, CONE + PARAMETER ( CZERO = ( 0.0D0, 0.0D0 ), + $ CONE = ( 1.0D0, 0.0D0 ) ) +* .. +* .. Local Scalars .. + LOGICAL LOWER, LQUERY, WANTZ + INTEGER IINFO, IMAX, INDE, INDWK2, INDRWK, ISCALE, + $ LLWORK, INDWK, LHTRD, LWTRD, IB, INDHOUS, + $ LIWMIN, LLRWK, LLWK2, LRWMIN, LWMIN + DOUBLE PRECISION ANRM, BIGNUM, EPS, RMAX, RMIN, SAFMIN, SIGMA, + $ SMLNUM +* .. +* .. External Functions .. + LOGICAL LSAME + INTEGER ILAENV + DOUBLE PRECISION DLAMCH, ZLANHB + EXTERNAL LSAME, DLAMCH, ZLANHB, ILAENV +* .. +* .. External Subroutines .. + EXTERNAL DSCAL, DSTERF, XERBLA, ZGEMM, ZLACPY, + $ ZLASCL, ZSTEDC, ZHETRD_HB2ST +* .. +* .. Intrinsic Functions .. + INTRINSIC DBLE, SQRT +* .. +* .. Executable Statements .. +* +* Test the input parameters. +* + WANTZ = LSAME( JOBZ, 'V' ) + LOWER = LSAME( UPLO, 'L' ) + LQUERY = ( LWORK.EQ.-1 .OR. LIWORK.EQ.-1 .OR. LRWORK.EQ.-1 ) +* + INFO = 0 + IF( N.LE.1 ) THEN + LWMIN = 1 + LRWMIN = 1 + LIWMIN = 1 + ELSE + IB = ILAENV( 18, 'ZHETRD_HB2ST', JOBZ, N, KD, -1, -1 ) + LHTRD = ILAENV( 19, 'ZHETRD_HB2ST', JOBZ, N, KD, IB, -1 ) + LWTRD = ILAENV( 20, 'ZHETRD_HB2ST', JOBZ, N, KD, IB, -1 ) + IF( WANTZ ) THEN + LWMIN = 2*N**2 + LRWMIN = 1 + 5*N + 2*N**2 + LIWMIN = 3 + 5*N + ELSE + LWMIN = MAX( N, LHTRD + LWTRD ) + LRWMIN = N + LIWMIN = 1 + END IF + END IF + IF( .NOT.( LSAME( JOBZ, 'N' ) ) ) THEN + INFO = -1 + ELSE IF( .NOT.( LOWER .OR. LSAME( UPLO, 'U' ) ) ) THEN + INFO = -2 + ELSE IF( N.LT.0 ) THEN + INFO = -3 + ELSE IF( KD.LT.0 ) THEN + INFO = -4 + ELSE IF( LDAB.LT.KD+1 ) THEN + INFO = -6 + ELSE IF( LDZ.LT.1 .OR. ( WANTZ .AND. LDZ.LT.N ) ) THEN + INFO = -9 + END IF +* + IF( INFO.EQ.0 ) THEN + WORK( 1 ) = LWMIN + RWORK( 1 ) = LRWMIN + IWORK( 1 ) = LIWMIN +* + IF( LWORK.LT.LWMIN .AND. .NOT.LQUERY ) THEN + INFO = -11 + ELSE IF( LRWORK.LT.LRWMIN .AND. .NOT.LQUERY ) THEN + INFO = -13 + ELSE IF( LIWORK.LT.LIWMIN .AND. .NOT.LQUERY ) THEN + INFO = -15 + END IF + END IF +* + IF( INFO.NE.0 ) THEN + CALL XERBLA( 'ZHBEVD_2STAGE', -INFO ) + RETURN + ELSE IF( LQUERY ) THEN + RETURN + END IF +* +* Quick return if possible +* + IF( N.EQ.0 ) + $ RETURN +* + IF( N.EQ.1 ) THEN + W( 1 ) = DBLE( AB( 1, 1 ) ) + IF( WANTZ ) + $ Z( 1, 1 ) = CONE + RETURN + END IF +* +* Get machine constants. +* + SAFMIN = DLAMCH( 'Safe minimum' ) + EPS = DLAMCH( 'Precision' ) + SMLNUM = SAFMIN / EPS + BIGNUM = ONE / SMLNUM + RMIN = SQRT( SMLNUM ) + RMAX = SQRT( BIGNUM ) +* +* Scale matrix to allowable range, if necessary. +* + ANRM = ZLANHB( 'M', UPLO, N, KD, AB, LDAB, RWORK ) + ISCALE = 0 + IF( ANRM.GT.ZERO .AND. ANRM.LT.RMIN ) THEN + ISCALE = 1 + SIGMA = RMIN / ANRM + ELSE IF( ANRM.GT.RMAX ) THEN + ISCALE = 1 + SIGMA = RMAX / ANRM + END IF + IF( ISCALE.EQ.1 ) THEN + IF( LOWER ) THEN + CALL ZLASCL( 'B', KD, KD, ONE, SIGMA, N, N, AB, LDAB, INFO ) + ELSE + CALL ZLASCL( 'Q', KD, KD, ONE, SIGMA, N, N, AB, LDAB, INFO ) + END IF + END IF +* +* Call ZHBTRD_HB2ST to reduce Hermitian band matrix to tridiagonal form. +* + INDE = 1 + INDRWK = INDE + N + LLRWK = LRWORK - INDRWK + 1 + INDHOUS = 1 + INDWK = INDHOUS + LHTRD + LLWORK = LWORK - INDWK + 1 + INDWK2 = INDWK + N*N + LLWK2 = LWORK - INDWK2 + 1 +* + CALL ZHETRD_HB2ST( "N", JOBZ, UPLO, N, KD, AB, LDAB, W, + $ RWORK( INDE ), WORK( INDHOUS ), LHTRD, + $ WORK( INDWK ), LLWORK, IINFO ) +* +* For eigenvalues only, call DSTERF. For eigenvectors, call ZSTEDC. +* + IF( .NOT.WANTZ ) THEN + CALL DSTERF( N, W, RWORK( INDE ), INFO ) + ELSE + CALL ZSTEDC( 'I', N, W, RWORK( INDE ), WORK, N, WORK( INDWK2 ), + $ LLWK2, RWORK( INDRWK ), LLRWK, IWORK, LIWORK, + $ INFO ) + CALL ZGEMM( 'N', 'N', N, N, N, CONE, Z, LDZ, WORK, N, CZERO, + $ WORK( INDWK2 ), N ) + CALL ZLACPY( 'A', N, N, WORK( INDWK2 ), N, Z, LDZ ) + END IF +* +* If matrix was scaled, then rescale eigenvalues appropriately. +* + IF( ISCALE.EQ.1 ) THEN + IF( INFO.EQ.0 ) THEN + IMAX = N + ELSE + IMAX = INFO - 1 + END IF + CALL DSCAL( IMAX, ONE / SIGMA, W, 1 ) + END IF +* + WORK( 1 ) = LWMIN + RWORK( 1 ) = LRWMIN + IWORK( 1 ) = LIWMIN + RETURN +* +* End of ZHBEVD_2STAGE +* + END |