dlaed0 - compute all eigenvalues and corresponding eigenvectors of an unreduced symmetric tridiagonal matrix using the divide and conquer method. Used by dstedc
SUBROUTINE DLAED0(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK, IWORK, INFO) INTEGER ICOMPQ, INFO, LDQ, LDQS, N, QSIZ INTEGER IWORK(*) DOUBLE PRECISION D(*), E(*), Q(LDQ,*), QSTORE(LDQS,*), WORK(*) SUBROUTINE DLAED0_64(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK, IWORK, INFO) INTEGER*8 ICOMPQ, INFO, LDQ, LDQS, N, QSIZ INTEGER*8 IWORK(*) DOUBLE PRECISION D(*), E(*), Q(LDQ,*), QSTORE(LDQS,*), WORK(*) F95 INTERFACE SUBROUTINE LAED0(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK, IWORK, INFO) INTEGER :: ICOMPQ, QSIZ, N, LDQ, LDQS, INFO INTEGER, DIMENSION(:) :: IWORK REAL(8), DIMENSION(:,:) :: Q, QSTORE REAL(8), DIMENSION(:) :: D, E, WORK SUBROUTINE LAED0_64(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK, IWORK, INFO) INTEGER(8) :: ICOMPQ, QSIZ, N, LDQ, LDQS, INFO INTEGER(8), DIMENSION(:) :: IWORK REAL(8), DIMENSION(:,:) :: Q, QSTORE REAL(8), DIMENSION(:) :: D, E, WORK C INTERFACE #include <sunperf.h> void dlaed0 (int icompq, int qsiz, int n, double *d, double *e, double *q, int ldq, double *qstore, int ldqs, int *info); void dlaed0_64 (long icompq, long qsiz, long n, double *d, double *e, double *q, long ldq, double *qstore, long ldqs, long *info);
Oracle Solaris Studio Performance Library dlaed0(3P)
NAME
dlaed0 - compute all eigenvalues and corresponding eigenvectors of an
unreduced symmetric tridiagonal matrix using the divide and conquer
method. Used by dstedc
SYNOPSIS
SUBROUTINE DLAED0(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK,
IWORK, INFO)
INTEGER ICOMPQ, INFO, LDQ, LDQS, N, QSIZ
INTEGER IWORK(*)
DOUBLE PRECISION D(*), E(*), Q(LDQ,*), QSTORE(LDQS,*), WORK(*)
SUBROUTINE DLAED0_64(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK,
IWORK, INFO)
INTEGER*8 ICOMPQ, INFO, LDQ, LDQS, N, QSIZ
INTEGER*8 IWORK(*)
DOUBLE PRECISION D(*), E(*), Q(LDQ,*), QSTORE(LDQS,*), WORK(*)
F95 INTERFACE
SUBROUTINE LAED0(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK,
IWORK, INFO)
INTEGER :: ICOMPQ, QSIZ, N, LDQ, LDQS, INFO
INTEGER, DIMENSION(:) :: IWORK
REAL(8), DIMENSION(:,:) :: Q, QSTORE
REAL(8), DIMENSION(:) :: D, E, WORK
SUBROUTINE LAED0_64(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK,
IWORK, INFO)
INTEGER(8) :: ICOMPQ, QSIZ, N, LDQ, LDQS, INFO
INTEGER(8), DIMENSION(:) :: IWORK
REAL(8), DIMENSION(:,:) :: Q, QSTORE
REAL(8), DIMENSION(:) :: D, E, WORK
C INTERFACE
#include <sunperf.h>
void dlaed0 (int icompq, int qsiz, int n, double *d, double *e, double
*q, int ldq, double *qstore, int ldqs, int *info);
void dlaed0_64 (long icompq, long qsiz, long n, double *d, double *e,
double *q, long ldq, double *qstore, long ldqs, long *info);
PURPOSE
dlaed0 computes all eigenvalues and corresponding eigenvectors of a
symmetric tridiagonal matrix using the divide and conquer method.
ARGUMENTS
ICOMPQ (input)
ICOMPQ is INTEGER
= 0: Compute eigenvalues only.
= 1: Compute eigenvectors of original dense symmetric matrix
also. On entry, Q contains the orthogonal matrix used to
reduce the original matrix to tridiagonal form.
= 2: Compute eigenvalues and eigenvectors of tridiagonal
matrix.
QSIZ (input)
QSIZ is INTEGER
The dimension of the orthogonal matrix used to reduce the
full matrix to tridiagonal form. QSIZ >= N if ICOMPQ = 1.
N (input)
N is INTEGER
The dimension of the symmetric tridiagonal matrix. N >= 0.
D (input/output)
D is DOUBLE PRECISION array, dimension (N)
On entry, the main diagonal of the tridiagonal matrix.
On exit, its eigenvalues.
E (input)
E is DOUBLE PRECISION array, dimension (N-1)
The off-diagonal elements of the tridiagonal matrix.
On exit, E has been destroyed.
Q (input/output)
Q is DOUBLE PRECISION array, dimension (LDQ, N)
On entry, Q must contain an N-by-N orthogonal matrix.
If ICOMPQ = 0 Q is not referenced.
If ICOMPQ = 1 On entry, Q is a subset of the columns of
the orthogonal matrix used to reduce the full matrix to
tridiagonal form corresponding to the subset of the full
matrix which is being decomposed at this time.
If ICOMPQ = 2 On entry, Q will be the identity matrix.
On exit, Q contains the eigenvectors of the tridiagonal
matrix.
LDQ (input)
LDQ is INTEGER
The leading dimension of the array Q. If eigenvectors are
desired, then LDQ >= max(1,N). In any case, LDQ >= 1.
QSTORE (output)
QSTORE is DOUBLE PRECISION array, dimension (LDQS, N)
Referenced only when ICOMPQ = 1. Used to store parts of the
eigenvector matrix when the updating matrix multiplies take
place.
LDQS (input)
LDQS is INTEGER
The leading dimension of the array QSTORE. If ICOMPQ = 1,
then LDQS >= max(1,N). In any case, LDQS >= 1.
WORK (output)
WORK is DOUBLE PRECISION array,
If ICOMPQ = 0 or 1, the dimension of WORK must be at least
1 + 3*N + 2*N*lg N + 3*N**2
( lg( N ) = smallest integer k
such that 2^k >= N )
If ICOMPQ = 2, the dimension of WORK must be at least
4*N + N**2.
IWORK (output)
IWORK is INTEGER array.
If ICOMPQ = 0 or 1, the dimension of IWORK must be at least
6 + 6*N + 5*N*lg N.
( lg( N ) = smallest integer k
such that 2^k >= N )
If ICOMPQ = 2, the dimension of IWORK must be at least
3 + 5*N.
INFO (output)
INFO is INTEGER
= 0: successful exit.
< 0: if INFO = -i, the i-th argument had an illegal value.
> 0: The algorithm failed to compute an eigenvalue while
working on the submatrix lying in rows and columns
INFO/(N+1) through mod(INFO,N+1).
7 Nov 2015 dlaed0(3P)