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authorjulie <julielangou@users.noreply.github.com>2011-10-06 06:53:11 +0000
committerjulie <julielangou@users.noreply.github.com>2011-10-06 06:53:11 +0000
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@@ -1,9 +1,132 @@
+*> \brief \b DSTEQR
+*
+* =========== DOCUMENTATION ===========
+*
+* Online html documentation available at
+* http://www.netlib.org/lapack/explore-html/
+*
+* Definition
+* ==========
+*
+* SUBROUTINE DSTEQR( COMPZ, N, D, E, Z, LDZ, WORK, INFO )
+*
+* .. Scalar Arguments ..
+* CHARACTER COMPZ
+* INTEGER INFO, LDZ, N
+* ..
+* .. Array Arguments ..
+* DOUBLE PRECISION D( * ), E( * ), WORK( * ), Z( LDZ, * )
+* ..
+*
+* Purpose
+* =======
+*
+*>\details \b Purpose:
+*>\verbatim
+*>
+*> DSTEQR computes all eigenvalues and, optionally, eigenvectors of a
+*> symmetric tridiagonal matrix using the implicit QL or QR method.
+*> The eigenvectors of a full or band symmetric matrix can also be found
+*> if DSYTRD or DSPTRD or DSBTRD has been used to reduce this matrix to
+*> tridiagonal form.
+*>
+*>\endverbatim
+*
+* Arguments
+* =========
+*
+*> \param[in] COMPZ
+*> \verbatim
+*> COMPZ is CHARACTER*1
+*> = 'N': Compute eigenvalues only.
+*> = 'V': Compute eigenvalues and eigenvectors of the original
+*> symmetric matrix. On entry, Z must contain the
+*> orthogonal matrix used to reduce the original matrix
+*> to tridiagonal form.
+*> = 'I': Compute eigenvalues and eigenvectors of the
+*> tridiagonal matrix. Z is initialized to the identity
+*> matrix.
+*> \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 diagonal elements of the tridiagonal matrix.
+*> 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.
+*> On exit, E has been destroyed.
+*> \endverbatim
+*>
+*> \param[in,out] Z
+*> \verbatim
+*> Z is DOUBLE PRECISION array, dimension (LDZ, N)
+*> On entry, if COMPZ = 'V', then Z contains the orthogonal
+*> matrix used in the reduction to tridiagonal form.
+*> On exit, if INFO = 0, then if COMPZ = 'V', Z contains the
+*> orthonormal eigenvectors of the original symmetric matrix,
+*> and if COMPZ = 'I', Z contains the orthonormal eigenvectors
+*> of the symmetric tridiagonal matrix.
+*> If COMPZ = '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
+*> eigenvectors are desired, then LDZ >= max(1,N).
+*> \endverbatim
+*>
+*> \param[out] WORK
+*> \verbatim
+*> WORK is DOUBLE PRECISION array, dimension (max(1,2*N-2))
+*> If COMPZ = 'N', then WORK 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: the algorithm has failed to find all the eigenvalues in
+*> a total of 30*N iterations; if INFO = i, then i
+*> elements of E have not converged to zero; on exit, D
+*> and E contain the elements of a symmetric tridiagonal
+*> matrix which is orthogonally similar to the original
+*> matrix.
+*> \endverbatim
+*>
+*
+* Authors
+* =======
+*
+*> \author Univ. of Tennessee
+*> \author Univ. of California Berkeley
+*> \author Univ. of Colorado Denver
+*> \author NAG Ltd.
+*
+*> \date November 2011
+*
+*> \ingroup auxOTHERcomputational
+*
+* =====================================================================
SUBROUTINE DSTEQR( COMPZ, N, D, E, Z, LDZ, WORK, INFO )
*
-* -- LAPACK routine (version 3.3.1) --
+* -- LAPACK computational routine (version 3.3.1) --
* -- 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 COMPZ
@@ -13,66 +136,6 @@
DOUBLE PRECISION D( * ), E( * ), WORK( * ), Z( LDZ, * )
* ..
*
-* Purpose
-* =======
-*
-* DSTEQR computes all eigenvalues and, optionally, eigenvectors of a
-* symmetric tridiagonal matrix using the implicit QL or QR method.
-* The eigenvectors of a full or band symmetric matrix can also be found
-* if DSYTRD or DSPTRD or DSBTRD has been used to reduce this matrix to
-* tridiagonal form.
-*
-* Arguments
-* =========
-*
-* COMPZ (input) CHARACTER*1
-* = 'N': Compute eigenvalues only.
-* = 'V': Compute eigenvalues and eigenvectors of the original
-* symmetric matrix. On entry, Z must contain the
-* orthogonal matrix used to reduce the original matrix
-* to tridiagonal form.
-* = 'I': Compute eigenvalues and eigenvectors of the
-* tridiagonal matrix. Z is initialized to the identity
-* matrix.
-*
-* N (input) INTEGER
-* The order of the matrix. N >= 0.
-*
-* D (input/output) DOUBLE PRECISION array, dimension (N)
-* On entry, the diagonal elements of the tridiagonal matrix.
-* 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.
-* On exit, E has been destroyed.
-*
-* Z (input/output) DOUBLE PRECISION array, dimension (LDZ, N)
-* On entry, if COMPZ = 'V', then Z contains the orthogonal
-* matrix used in the reduction to tridiagonal form.
-* On exit, if INFO = 0, then if COMPZ = 'V', Z contains the
-* orthonormal eigenvectors of the original symmetric matrix,
-* and if COMPZ = 'I', Z contains the orthonormal eigenvectors
-* of the symmetric tridiagonal matrix.
-* If COMPZ = 'N', then Z is not referenced.
-*
-* LDZ (input) INTEGER
-* The leading dimension of the array Z. LDZ >= 1, and if
-* eigenvectors are desired, then LDZ >= max(1,N).
-*
-* WORK (workspace) DOUBLE PRECISION array, dimension (max(1,2*N-2))
-* If COMPZ = 'N', then WORK is not referenced.
-*
-* INFO (output) INTEGER
-* = 0: successful exit
-* < 0: if INFO = -i, the i-th argument had an illegal value
-* > 0: the algorithm has failed to find all the eigenvalues in
-* a total of 30*N iterations; if INFO = i, then i
-* elements of E have not converged to zero; on exit, D
-* and E contain the elements of a symmetric tridiagonal
-* matrix which is orthogonally similar to the original
-* matrix.
-*
* =====================================================================
*
* .. Parameters ..