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author | julie <julielangou@users.noreply.github.com> | 2011-10-06 06:53:11 +0000 |
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committer | julie <julielangou@users.noreply.github.com> | 2011-10-06 06:53:11 +0000 |
commit | e1d39294aee16fa6db9ba079b14442358217db71 (patch) | |
tree | 30e5aa04c1f6596991fda5334f63dfb9b8027849 /SRC/dstevd.f | |
parent | 5fe0466a14e395641f4f8a300ecc9dcb8058081b (diff) |
Integrating Doxygen in comments
Diffstat (limited to 'SRC/dstevd.f')
-rw-r--r-- | SRC/dstevd.f | 240 |
1 files changed, 158 insertions, 82 deletions
diff --git a/SRC/dstevd.f b/SRC/dstevd.f index b90f7383..5a864d4a 100644 --- a/SRC/dstevd.f +++ b/SRC/dstevd.f @@ -1,10 +1,166 @@ +*> \brief <b> DSTEVD computes the eigenvalues and, optionally, the left and/or right eigenvectors for OTHER matrices</b> +* +* =========== DOCUMENTATION =========== +* +* Online html documentation available at +* http://www.netlib.org/lapack/explore-html/ +* +* Definition +* ========== +* +* SUBROUTINE DSTEVD( JOBZ, N, D, E, Z, LDZ, WORK, LWORK, IWORK, +* LIWORK, INFO ) +* +* .. Scalar Arguments .. +* CHARACTER JOBZ +* INTEGER INFO, LDZ, LIWORK, LWORK, N +* .. +* .. Array Arguments .. +* INTEGER IWORK( * ) +* DOUBLE PRECISION D( * ), E( * ), WORK( * ), Z( LDZ, * ) +* .. +* +* Purpose +* ======= +* +*>\details \b Purpose: +*>\verbatim +*> +*> DSTEVD computes all eigenvalues and, optionally, eigenvectors of a +*> real symmetric tridiagonal matrix. 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. +*> \endverbatim +*> +*> \param[in] N +*> \verbatim +*> N is INTEGER +*> The order of the matrix. N >= 0. +*> \endverbatim +*> +*> \param[in,out] D +*> \verbatim +*> D is DOUBLE PRECISION array, dimension (N) +*> On entry, the n diagonal elements of the tridiagonal matrix +*> A. +*> On exit, if INFO = 0, the eigenvalues in ascending order. +*> \endverbatim +*> +*> \param[in,out] E +*> \verbatim +*> E is DOUBLE PRECISION array, dimension (N-1) +*> On entry, the (n-1) subdiagonal elements of the tridiagonal +*> matrix A, stored in elements 1 to N-1 of E. +*> On exit, the contents of E are destroyed. +*> \endverbatim +*> +*> \param[out] Z +*> \verbatim +*> Z is DOUBLE PRECISION 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 D(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 DOUBLE PRECISION array, +*> dimension (LWORK) +*> On exit, if INFO = 0, WORK(1) returns the optimal LWORK. +*> \endverbatim +*> +*> \param[in] LWORK +*> \verbatim +*> LWORK is INTEGER +*> The dimension of the array WORK. +*> If JOBZ = 'N' or N <= 1 then LWORK must be at least 1. +*> If JOBZ = 'V' and N > 1 then LWORK must be at least +*> ( 1 + 4*N + N**2 ). +*> \endverbatim +*> \verbatim +*> If LWORK = -1, then a workspace query is assumed; the routine +*> only calculates the optimal sizes of the WORK and IWORK +*> arrays, returns these values as the first entries of the WORK +*> and IWORK arrays, and no error message related to LWORK 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 the array IWORK. +*> If JOBZ = 'N' or N <= 1 then LIWORK must be at least 1. +*> If JOBZ = 'V' and N > 1 then LIWORK must be at least 3+5*N. +*> \endverbatim +*> \verbatim +*> If LIWORK = -1, then a workspace query is assumed; the +*> routine only calculates the optimal sizes of the WORK and +*> IWORK arrays, returns these values as the first entries of +*> the WORK and IWORK arrays, and no error message related to +*> LWORK 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 E 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 2011 +* +*> \ingroup doubleOTHEReigen +* +* ===================================================================== SUBROUTINE DSTEVD( JOBZ, N, D, E, Z, LDZ, WORK, LWORK, IWORK, $ LIWORK, INFO ) * -* -- LAPACK driver routine (version 3.2) -- +* -- LAPACK eigen routine (version 3.2) -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- -* November 2006 +* November 2011 * * .. Scalar Arguments .. CHARACTER JOBZ @@ -15,86 +171,6 @@ DOUBLE PRECISION D( * ), E( * ), WORK( * ), Z( LDZ, * ) * .. * -* Purpose -* ======= -* -* DSTEVD computes all eigenvalues and, optionally, eigenvectors of a -* real symmetric tridiagonal matrix. 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. -* -* Arguments -* ========= -* -* JOBZ (input) CHARACTER*1 -* = 'N': Compute eigenvalues only; -* = 'V': Compute eigenvalues and eigenvectors. -* -* N (input) INTEGER -* The order of the matrix. N >= 0. -* -* D (input/output) DOUBLE PRECISION array, dimension (N) -* On entry, the n diagonal elements of the tridiagonal matrix -* A. -* On exit, if INFO = 0, the eigenvalues in ascending order. -* -* E (input/output) DOUBLE PRECISION array, dimension (N-1) -* On entry, the (n-1) subdiagonal elements of the tridiagonal -* matrix A, stored in elements 1 to N-1 of E. -* On exit, the contents of E are destroyed. -* -* Z (output) DOUBLE PRECISION 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 D(i). -* If JOBZ = 'N', then Z is not referenced. -* -* 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 (LWORK) -* On exit, if INFO = 0, WORK(1) returns the optimal LWORK. -* -* LWORK (input) INTEGER -* The dimension of the array WORK. -* If JOBZ = 'N' or N <= 1 then LWORK must be at least 1. -* If JOBZ = 'V' and N > 1 then LWORK must be at least -* ( 1 + 4*N + N**2 ). -* -* If LWORK = -1, then a workspace query is assumed; the routine -* only calculates the optimal sizes of the WORK and IWORK -* arrays, returns these values as the first entries of the WORK -* and IWORK arrays, and no error message related to LWORK or -* LIWORK is issued by XERBLA. -* -* IWORK (workspace/output) INTEGER array, dimension (MAX(1,LIWORK)) -* On exit, if INFO = 0, IWORK(1) returns the optimal LIWORK. -* -* LIWORK (input) INTEGER -* The dimension of the array IWORK. -* If JOBZ = 'N' or N <= 1 then LIWORK must be at least 1. -* If JOBZ = 'V' and N > 1 then 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 and -* IWORK arrays, returns these values as the first entries of -* the WORK and IWORK arrays, and no error message related to -* LWORK or LIWORK is issued by XERBLA. -* -* INFO (output) 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 E did not converge to zero. -* * ===================================================================== * * .. Parameters .. |