--- rpl/lapack/lapack/dpteqr.f 2010/12/21 13:53:37 1.7
+++ rpl/lapack/lapack/dpteqr.f 2023/08/07 08:39:05 1.18
@@ -1,9 +1,151 @@
+*> \brief \b DPTEQR
+*
+* =========== DOCUMENTATION ===========
+*
+* Online html documentation available at
+* http://www.netlib.org/lapack/explore-html/
+*
+*> \htmlonly
+*> Download DPTEQR + dependencies
+*>
+*> [TGZ]
+*>
+*> [ZIP]
+*>
+*> [TXT]
+*> \endhtmlonly
+*
+* Definition:
+* ===========
+*
+* SUBROUTINE DPTEQR( 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, * )
+* ..
+*
+*
+*> \par Purpose:
+* =============
+*>
+*> \verbatim
+*>
+*> DPTEQR computes all eigenvalues and, optionally, eigenvectors of a
+*> symmetric positive definite tridiagonal matrix by first factoring the
+*> matrix using DPTTRF, and then calling DBDSQR to compute the singular
+*> values of the bidiagonal factor.
+*>
+*> This routine computes the eigenvalues of the positive definite
+*> tridiagonal matrix to high relative accuracy. This means that if the
+*> eigenvalues range over many orders of magnitude in size, then the
+*> small eigenvalues and corresponding eigenvectors will be computed
+*> more accurately than, for example, with the standard QR method.
+*>
+*> The eigenvectors of a full or band symmetric positive definite matrix
+*> can also be found if DSYTRD, DSPTRD, or DSBTRD has been used to
+*> reduce this matrix to tridiagonal form. (The reduction to tridiagonal
+*> form, however, may preclude the possibility of obtaining high
+*> relative accuracy in the small eigenvalues of the original matrix, if
+*> these eigenvalues range over many orders of magnitude.)
+*> \endverbatim
+*
+* Arguments:
+* ==========
+*
+*> \param[in] COMPZ
+*> \verbatim
+*> COMPZ is CHARACTER*1
+*> = 'N': Compute eigenvalues only.
+*> = 'V': Compute eigenvectors of original symmetric
+*> matrix also. Array Z contains the orthogonal
+*> matrix used to reduce the original matrix to
+*> tridiagonal form.
+*> = 'I': Compute eigenvectors of tridiagonal matrix also.
+*> \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.
+*> On normal exit, D contains the eigenvalues, in descending
+*> 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', the orthogonal matrix used in the
+*> reduction to tridiagonal form.
+*> On exit, if COMPZ = 'V', the orthonormal eigenvectors of the
+*> original symmetric matrix;
+*> if COMPZ = 'I', the orthonormal eigenvectors of the
+*> tridiagonal matrix.
+*> If INFO > 0 on exit, Z contains the eigenvectors associated
+*> with only the stored eigenvalues.
+*> 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
+*> COMPZ = 'V' or 'I', LDZ >= max(1,N).
+*> \endverbatim
+*>
+*> \param[out] WORK
+*> \verbatim
+*> WORK is DOUBLE PRECISION array, dimension (4*N)
+*> \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, and i is:
+*> <= N the Cholesky factorization of the matrix could
+*> not be performed because the i-th principal minor
+*> was not positive definite.
+*> > N the SVD algorithm failed to converge;
+*> if INFO = N+i, i off-diagonal elements of the
+*> bidiagonal factor did not converge to zero.
+*> \endverbatim
+*
+* Authors:
+* ========
+*
+*> \author Univ. of Tennessee
+*> \author Univ. of California Berkeley
+*> \author Univ. of Colorado Denver
+*> \author NAG Ltd.
+*
+*> \ingroup doublePTcomputational
+*
+* =====================================================================
SUBROUTINE DPTEQR( COMPZ, N, D, E, Z, LDZ, WORK, INFO )
*
-* -- LAPACK routine (version 3.2) --
+* -- LAPACK computational routine --
* -- LAPACK is a software package provided by Univ. of Tennessee, --
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
-* November 2006
*
* .. Scalar Arguments ..
CHARACTER COMPZ
@@ -13,80 +155,6 @@
DOUBLE PRECISION D( * ), E( * ), WORK( * ), Z( LDZ, * )
* ..
*
-* Purpose
-* =======
-*
-* DPTEQR computes all eigenvalues and, optionally, eigenvectors of a
-* symmetric positive definite tridiagonal matrix by first factoring the
-* matrix using DPTTRF, and then calling DBDSQR to compute the singular
-* values of the bidiagonal factor.
-*
-* This routine computes the eigenvalues of the positive definite
-* tridiagonal matrix to high relative accuracy. This means that if the
-* eigenvalues range over many orders of magnitude in size, then the
-* small eigenvalues and corresponding eigenvectors will be computed
-* more accurately than, for example, with the standard QR method.
-*
-* The eigenvectors of a full or band symmetric positive definite matrix
-* can also be found if DSYTRD, DSPTRD, or DSBTRD has been used to
-* reduce this matrix to tridiagonal form. (The reduction to tridiagonal
-* form, however, may preclude the possibility of obtaining high
-* relative accuracy in the small eigenvalues of the original matrix, if
-* these eigenvalues range over many orders of magnitude.)
-*
-* Arguments
-* =========
-*
-* COMPZ (input) CHARACTER*1
-* = 'N': Compute eigenvalues only.
-* = 'V': Compute eigenvectors of original symmetric
-* matrix also. Array Z contains the orthogonal
-* matrix used to reduce the original matrix to
-* tridiagonal form.
-* = 'I': Compute eigenvectors of tridiagonal matrix also.
-*
-* 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.
-* On normal exit, D contains the eigenvalues, in descending
-* 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', the orthogonal matrix used in the
-* reduction to tridiagonal form.
-* On exit, if COMPZ = 'V', the orthonormal eigenvectors of the
-* original symmetric matrix;
-* if COMPZ = 'I', the orthonormal eigenvectors of the
-* tridiagonal matrix.
-* If INFO > 0 on exit, Z contains the eigenvectors associated
-* with only the stored eigenvalues.
-* If COMPZ = 'N', then Z is not referenced.
-*
-* LDZ (input) INTEGER
-* The leading dimension of the array Z. LDZ >= 1, and if
-* COMPZ = 'V' or 'I', LDZ >= max(1,N).
-*
-* WORK (workspace) DOUBLE PRECISION array, dimension (4*N)
-*
-* INFO (output) INTEGER
-* = 0: successful exit.
-* < 0: if INFO = -i, the i-th argument had an illegal value.
-* > 0: if INFO = i, and i is:
-* <= N the Cholesky factorization of the matrix could
-* not be performed because the i-th principal minor
-* was not positive definite.
-* > N the SVD algorithm failed to converge;
-* if INFO = N+i, i off-diagonal elements of the
-* bidiagonal factor did not converge to zero.
-*
* =====================================================================
*
* .. Parameters ..