slaed0 - compute all eigenvalues and corresponding eigenvectors of an unreduced symmetric tridiagonal matrix using the divide and conquer method. Used by sstedc
SUBROUTINE SLAED0(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK, IWORK, INFO) INTEGER ICOMPQ, INFO, LDQ, LDQS, N, QSIZ INTEGER IWORK(*) REAL D(*), E(*), Q(LDQ,*), QSTORE(LDQS,*), WORK(*) SUBROUTINE SLAED0_64(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK, IWORK, INFO) INTEGER*8 ICOMPQ, INFO, LDQ, LDQS, N, QSIZ INTEGER*8 IWORK(*) REAL D(*), E(*), Q(LDQ,*), QSTORE(LDQS,*), WORK(*) F95 INTERFACE SUBROUTINE LAED0(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK, IWORK, INFO) REAL, DIMENSION(:,:) :: Q, QSTORE INTEGER :: ICOMPQ, QSIZ, N, LDQ, LDQS, INFO INTEGER, DIMENSION(:) :: IWORK REAL, DIMENSION(:) :: D, E, WORK SUBROUTINE LAED0_64(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK, IWORK, INFO) REAL, DIMENSION(:,:) :: Q, QSTORE INTEGER(8) :: ICOMPQ, QSIZ, N, LDQ, LDQS, INFO INTEGER(8), DIMENSION(:) :: IWORK REAL, DIMENSION(:) :: D, E, WORK C INTERFACE #include <sunperf.h> void slaed0 (int icompq, int qsiz, int n, float *d, float *e, float *q, int ldq, float *qstore, int ldqs, int *info); void slaed0_64 (long icompq, long qsiz, long n, float *d, float *e, float *q, long ldq, float *qstore, long ldqs, long *info);
Oracle Solaris Studio Performance Library slaed0(3P)
NAME
slaed0 - compute all eigenvalues and corresponding eigenvectors of an
unreduced symmetric tridiagonal matrix using the divide and conquer
method. Used by sstedc
SYNOPSIS
SUBROUTINE SLAED0(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK,
IWORK, INFO)
INTEGER ICOMPQ, INFO, LDQ, LDQS, N, QSIZ
INTEGER IWORK(*)
REAL D(*), E(*), Q(LDQ,*), QSTORE(LDQS,*), WORK(*)
SUBROUTINE SLAED0_64(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK,
IWORK, INFO)
INTEGER*8 ICOMPQ, INFO, LDQ, LDQS, N, QSIZ
INTEGER*8 IWORK(*)
REAL D(*), E(*), Q(LDQ,*), QSTORE(LDQS,*), WORK(*)
F95 INTERFACE
SUBROUTINE LAED0(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK,
IWORK, INFO)
REAL, DIMENSION(:,:) :: Q, QSTORE
INTEGER :: ICOMPQ, QSIZ, N, LDQ, LDQS, INFO
INTEGER, DIMENSION(:) :: IWORK
REAL, DIMENSION(:) :: D, E, WORK
SUBROUTINE LAED0_64(ICOMPQ, QSIZ, N, D, E, Q, LDQ, QSTORE, LDQS, WORK,
IWORK, INFO)
REAL, DIMENSION(:,:) :: Q, QSTORE
INTEGER(8) :: ICOMPQ, QSIZ, N, LDQ, LDQS, INFO
INTEGER(8), DIMENSION(:) :: IWORK
REAL, DIMENSION(:) :: D, E, WORK
C INTERFACE
#include <sunperf.h>
void slaed0 (int icompq, int qsiz, int n, float *d, float *e, float *q,
int ldq, float *qstore, int ldqs, int *info);
void slaed0_64 (long icompq, long qsiz, long n, float *d, float *e,
float *q, long ldq, float *qstore, long ldqs, long *info);
PURPOSE
slaed0 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 REAL array, dimension (N)
On entry, the main diagonal of the tridiagonal matrix.
On exit, its eigenvalues.
E (input)
E is REAL array, dimension (N-1)
The off-diagonal elements of the tridiagonal matrix.
On exit, E has been destroyed.
Q (input/output)
Q is REAL 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 REAL 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 REAL 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 slaed0(3P)