--- rpl/lapack/lapack/dsygvx.f 2011/07/22 07:38:11 1.9 +++ rpl/lapack/lapack/dsygvx.f 2011/11/21 20:43:05 1.10 @@ -1,11 +1,299 @@ +*> \brief \b DSYGST +* +* =========== DOCUMENTATION =========== +* +* Online html documentation available at +* http://www.netlib.org/lapack/explore-html/ +* +*> \htmlonly +*> Download DSYGVX + dependencies +*> +*> [TGZ] +*> +*> [ZIP] +*> +*> [TXT] +*> \endhtmlonly +* +* Definition: +* =========== +* +* SUBROUTINE DSYGVX( ITYPE, JOBZ, RANGE, UPLO, N, A, LDA, B, LDB, +* VL, VU, IL, IU, ABSTOL, M, W, Z, LDZ, WORK, +* LWORK, IWORK, IFAIL, INFO ) +* +* .. Scalar Arguments .. +* CHARACTER JOBZ, RANGE, UPLO +* INTEGER IL, INFO, ITYPE, IU, LDA, LDB, LDZ, LWORK, M, N +* DOUBLE PRECISION ABSTOL, VL, VU +* .. +* .. Array Arguments .. +* INTEGER IFAIL( * ), IWORK( * ) +* DOUBLE PRECISION A( LDA, * ), B( LDB, * ), W( * ), WORK( * ), +* $ Z( LDZ, * ) +* .. +* +* +*> \par Purpose: +* ============= +*> +*> \verbatim +*> +*> DSYGVX computes selected eigenvalues, and optionally, eigenvectors +*> of a real generalized symmetric-definite eigenproblem, of the form +*> A*x=(lambda)*B*x, A*Bx=(lambda)*x, or B*A*x=(lambda)*x. Here A +*> and B are assumed to be symmetric and B is also positive definite. +*> Eigenvalues and eigenvectors can be selected by specifying either a +*> range of values or a range of indices for the desired eigenvalues. +*> \endverbatim +* +* Arguments: +* ========== +* +*> \param[in] ITYPE +*> \verbatim +*> ITYPE is INTEGER +*> Specifies the problem type to be solved: +*> = 1: A*x = (lambda)*B*x +*> = 2: A*B*x = (lambda)*x +*> = 3: B*A*x = (lambda)*x +*> \endverbatim +*> +*> \param[in] JOBZ +*> \verbatim +*> JOBZ is CHARACTER*1 +*> = 'N': Compute eigenvalues only; +*> = 'V': Compute eigenvalues and eigenvectors. +*> \endverbatim +*> +*> \param[in] RANGE +*> \verbatim +*> RANGE is CHARACTER*1 +*> = 'A': all eigenvalues will be found. +*> = 'V': all eigenvalues in the half-open interval (VL,VU] +*> will be found. +*> = 'I': the IL-th through IU-th eigenvalues will be found. +*> \endverbatim +*> +*> \param[in] UPLO +*> \verbatim +*> UPLO is CHARACTER*1 +*> = 'U': Upper triangle of A and B are stored; +*> = 'L': Lower triangle of A and B are stored. +*> \endverbatim +*> +*> \param[in] N +*> \verbatim +*> N is INTEGER +*> The order of the matrix pencil (A,B). N >= 0. +*> \endverbatim +*> +*> \param[in,out] A +*> \verbatim +*> A is DOUBLE PRECISION array, dimension (LDA, N) +*> On entry, the symmetric matrix A. If UPLO = 'U', the +*> leading N-by-N upper triangular part of A contains the +*> upper triangular part of the matrix A. If UPLO = 'L', +*> the leading N-by-N lower triangular part of A contains +*> the lower triangular part of the matrix A. +*> +*> On exit, the lower triangle (if UPLO='L') or the upper +*> triangle (if UPLO='U') of A, including the diagonal, is +*> destroyed. +*> \endverbatim +*> +*> \param[in] LDA +*> \verbatim +*> LDA is INTEGER +*> The leading dimension of the array A. LDA >= max(1,N). +*> \endverbatim +*> +*> \param[in,out] B +*> \verbatim +*> B is DOUBLE PRECISION array, dimension (LDB, N) +*> On entry, the symmetric matrix B. If UPLO = 'U', the +*> leading N-by-N upper triangular part of B contains the +*> upper triangular part of the matrix B. If UPLO = 'L', +*> the leading N-by-N lower triangular part of B contains +*> the lower triangular part of the matrix B. +*> +*> On exit, if INFO <= N, the part of B containing the matrix is +*> overwritten by the triangular factor U or L from the Cholesky +*> factorization B = U**T*U or B = L*L**T. +*> \endverbatim +*> +*> \param[in] LDB +*> \verbatim +*> LDB is INTEGER +*> The leading dimension of the array B. LDB >= max(1,N). +*> \endverbatim +*> +*> \param[in] VL +*> \verbatim +*> VL is DOUBLE PRECISION +*> \endverbatim +*> +*> \param[in] VU +*> \verbatim +*> VU is DOUBLE PRECISION +*> If RANGE='V', the lower and upper bounds of the interval to +*> be searched for eigenvalues. VL < VU. +*> Not referenced if RANGE = 'A' or 'I'. +*> \endverbatim +*> +*> \param[in] IL +*> \verbatim +*> IL is INTEGER +*> \endverbatim +*> +*> \param[in] IU +*> \verbatim +*> IU is INTEGER +*> If RANGE='I', the indices (in ascending order) of the +*> smallest and largest eigenvalues to be returned. +*> 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. +*> Not referenced if RANGE = 'A' or 'V'. +*> \endverbatim +*> +*> \param[in] ABSTOL +*> \verbatim +*> ABSTOL is DOUBLE PRECISION +*> The absolute error tolerance for the eigenvalues. +*> 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 +*> +*> ABSTOL + EPS * max( |a|,|b| ) , +*> +*> 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 C to tridiagonal form, where C is the symmetric +*> matrix of the standard symmetric problem to which the +*> generalized problem is transformed. +*> +*> 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 +*> +*> \param[out] M +*> \verbatim +*> M is INTEGER +*> The total number of eigenvalues found. 0 <= M <= N. +*> If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1. +*> \endverbatim +*> +*> \param[out] W +*> \verbatim +*> W is DOUBLE PRECISION array, dimension (N) +*> On normal exit, the first M elements contain the selected +*> eigenvalues in ascending order. +*> \endverbatim +*> +*> \param[out] Z +*> \verbatim +*> Z is DOUBLE PRECISION array, dimension (LDZ, max(1,M)) +*> If JOBZ = 'N', then Z is not referenced. +*> If JOBZ = 'V', then if INFO = 0, the first M columns of Z +*> contain the orthonormal eigenvectors of the matrix A +*> corresponding to the selected eigenvalues, with the i-th +*> column of Z holding the eigenvector associated with W(i). +*> The eigenvectors are normalized as follows: +*> if ITYPE = 1 or 2, Z**T*B*Z = I; +*> if ITYPE = 3, Z**T*inv(B)*Z = I. +*> +*> If an eigenvector fails to converge, then that column of Z +*> contains the latest approximation to the eigenvector, and the +*> index of the eigenvector is returned in IFAIL. +*> Note: the user must ensure that at least max(1,M) columns are +*> supplied in the array Z; if RANGE = 'V', the exact value of M +*> is not known in advance and an upper bound must be used. +*> \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 DOUBLE PRECISION 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 >= max(1,8*N). +*> For optimal efficiency, LWORK >= (NB+3)*N, +*> where NB is the blocksize for DSYTRD returned by ILAENV. +*> +*> 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 +*> message related to LWORK is issued by XERBLA. +*> \endverbatim +*> +*> \param[out] IWORK +*> \verbatim +*> IWORK is INTEGER array, dimension (5*N) +*> \endverbatim +*> +*> \param[out] IFAIL +*> \verbatim +*> IFAIL is INTEGER array, dimension (N) +*> If JOBZ = 'V', then if INFO = 0, the first M elements of +*> IFAIL are zero. If INFO > 0, then IFAIL contains the +*> indices of the eigenvectors that failed to converge. +*> If JOBZ = 'N', then IFAIL is not referenced. +*> \endverbatim +*> +*> \param[out] INFO +*> \verbatim +*> INFO is INTEGER +*> = 0: successful exit +*> < 0: if INFO = -i, the i-th argument had an illegal value +*> > 0: DPOTRF or DSYEVX returned an error code: +*> <= N: if INFO = i, DSYEVX failed to converge; +*> i eigenvectors failed to converge. Their indices +*> are stored in array IFAIL. +*> > N: if INFO = N + i, for 1 <= i <= N, then the leading +*> minor of order i of B is not positive definite. +*> The factorization of B could not be completed and +*> no eigenvalues or eigenvectors were computed. +*> \endverbatim +* +* Authors: +* ======== +* +*> \author Univ. of Tennessee +*> \author Univ. of California Berkeley +*> \author Univ. of Colorado Denver +*> \author NAG Ltd. +* +*> \date November 2011 +* +*> \ingroup doubleSYeigen +* +*> \par Contributors: +* ================== +*> +*> Mark Fahey, Department of Mathematics, Univ. of Kentucky, USA +* +* ===================================================================== SUBROUTINE DSYGVX( ITYPE, JOBZ, RANGE, UPLO, N, A, LDA, B, LDB, $ VL, VU, IL, IU, ABSTOL, M, W, Z, LDZ, WORK, $ LWORK, IWORK, IFAIL, INFO ) * -* -- LAPACK driver routine (version 3.3.1) -- +* -- LAPACK driver routine (version 3.4.0) -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- -* -- April 2011 -- +* November 2011 * * .. Scalar Arguments .. CHARACTER JOBZ, RANGE, UPLO @@ -18,170 +306,6 @@ $ Z( LDZ, * ) * .. * -* Purpose -* ======= -* -* DSYGVX computes selected eigenvalues, and optionally, eigenvectors -* of a real generalized symmetric-definite eigenproblem, of the form -* A*x=(lambda)*B*x, A*Bx=(lambda)*x, or B*A*x=(lambda)*x. Here A -* and B are assumed to be symmetric and B is also positive definite. -* Eigenvalues and eigenvectors can be selected by specifying either a -* range of values or a range of indices for the desired eigenvalues. -* -* Arguments -* ========= -* -* ITYPE (input) INTEGER -* Specifies the problem type to be solved: -* = 1: A*x = (lambda)*B*x -* = 2: A*B*x = (lambda)*x -* = 3: B*A*x = (lambda)*x -* -* JOBZ (input) CHARACTER*1 -* = 'N': Compute eigenvalues only; -* = 'V': Compute eigenvalues and eigenvectors. -* -* RANGE (input) CHARACTER*1 -* = 'A': all eigenvalues will be found. -* = 'V': all eigenvalues in the half-open interval (VL,VU] -* will be found. -* = 'I': the IL-th through IU-th eigenvalues will be found. -* -* UPLO (input) CHARACTER*1 -* = 'U': Upper triangle of A and B are stored; -* = 'L': Lower triangle of A and B are stored. -* -* N (input) INTEGER -* The order of the matrix pencil (A,B). N >= 0. -* -* A (input/output) DOUBLE PRECISION array, dimension (LDA, N) -* On entry, the symmetric matrix A. If UPLO = 'U', the -* leading N-by-N upper triangular part of A contains the -* upper triangular part of the matrix A. If UPLO = 'L', -* the leading N-by-N lower triangular part of A contains -* the lower triangular part of the matrix A. -* -* On exit, the lower triangle (if UPLO='L') or the upper -* triangle (if UPLO='U') of A, including the diagonal, is -* destroyed. -* -* LDA (input) INTEGER -* The leading dimension of the array A. LDA >= max(1,N). -* -* B (input/output) DOUBLE PRECISION array, dimension (LDB, N) -* On entry, the symmetric matrix B. If UPLO = 'U', the -* leading N-by-N upper triangular part of B contains the -* upper triangular part of the matrix B. If UPLO = 'L', -* the leading N-by-N lower triangular part of B contains -* the lower triangular part of the matrix B. -* -* On exit, if INFO <= N, the part of B containing the matrix is -* overwritten by the triangular factor U or L from the Cholesky -* factorization B = U**T*U or B = L*L**T. -* -* LDB (input) INTEGER -* The leading dimension of the array B. LDB >= max(1,N). -* -* VL (input) DOUBLE PRECISION -* VU (input) DOUBLE PRECISION -* If RANGE='V', the lower and upper bounds of the interval to -* be searched for eigenvalues. VL < VU. -* Not referenced if RANGE = 'A' or 'I'. -* -* IL (input) INTEGER -* IU (input) INTEGER -* If RANGE='I', the indices (in ascending order) of the -* smallest and largest eigenvalues to be returned. -* 1 <= IL <= IU <= N, if N > 0; IL = 1 and IU = 0 if N = 0. -* Not referenced if RANGE = 'A' or 'V'. -* -* ABSTOL (input) DOUBLE PRECISION -* The absolute error tolerance for the eigenvalues. -* 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 -* -* ABSTOL + EPS * max( |a|,|b| ) , -* -* 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. -* -* 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'). -* -* M (output) INTEGER -* The total number of eigenvalues found. 0 <= M <= N. -* If RANGE = 'A', M = N, and if RANGE = 'I', M = IU-IL+1. -* -* W (output) DOUBLE PRECISION array, dimension (N) -* On normal exit, the first M elements contain the selected -* eigenvalues in ascending order. -* -* Z (output) DOUBLE PRECISION array, dimension (LDZ, max(1,M)) -* If JOBZ = 'N', then Z is not referenced. -* If JOBZ = 'V', then if INFO = 0, the first M columns of Z -* contain the orthonormal eigenvectors of the matrix A -* corresponding to the selected eigenvalues, with the i-th -* column of Z holding the eigenvector associated with W(i). -* The eigenvectors are normalized as follows: -* if ITYPE = 1 or 2, Z**T*B*Z = I; -* if ITYPE = 3, Z**T*inv(B)*Z = I. -* -* If an eigenvector fails to converge, then that column of Z -* contains the latest approximation to the eigenvector, and the -* index of the eigenvector is returned in IFAIL. -* Note: the user must ensure that at least max(1,M) columns are -* supplied in the array Z; if RANGE = 'V', the exact value of M -* is not known in advance and an upper bound must be used. -* -* LDZ (input) INTEGER -* The leading dimension of the array Z. LDZ >= 1, and if -* JOBZ = 'V', LDZ >= max(1,N). -* -* WORK (workspace/output) DOUBLE PRECISION array, dimension (MAX(1,LWORK)) -* On exit, if INFO = 0, WORK(1) returns the optimal LWORK. -* -* LWORK (input) INTEGER -* The length of the array WORK. LWORK >= max(1,8*N). -* For optimal efficiency, LWORK >= (NB+3)*N, -* where NB is the blocksize for DSYTRD returned by ILAENV. -* -* 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 -* message related to LWORK is issued by XERBLA. -* -* IWORK (workspace) INTEGER array, dimension (5*N) -* -* IFAIL (output) INTEGER array, dimension (N) -* If JOBZ = 'V', then if INFO = 0, the first M elements of -* IFAIL are zero. If INFO > 0, then IFAIL contains the -* indices of the eigenvectors that failed to converge. -* If JOBZ = 'N', then IFAIL is not referenced. -* -* INFO (output) INTEGER -* = 0: successful exit -* < 0: if INFO = -i, the i-th argument had an illegal value -* > 0: DPOTRF or DSYEVX returned an error code: -* <= N: if INFO = i, DSYEVX failed to converge; -* i eigenvectors failed to converge. Their indices -* are stored in array IFAIL. -* > N: if INFO = N + i, for 1 <= i <= N, then the leading -* minor of order i of B is not positive definite. -* The factorization of B could not be completed and -* no eigenvalues or eigenvectors were computed. -* -* Further Details -* =============== -* -* Based on contributions by -* Mark Fahey, Department of Mathematics, Univ. of Kentucky, USA -* * ===================================================================== * * .. Parameters ..