dsyev
dsyev - compute all eigenvalues and, optionally, eigenvectors of a real symmetric matrix A
SUBROUTINE DSYEV( JOBZ, UPLO, N, A, LDA, W, WORK, LDWORK, INFO)
CHARACTER * 1 JOBZ, UPLO
INTEGER N, LDA, LDWORK, INFO
DOUBLE PRECISION A(LDA,*), W(*), WORK(*)
SUBROUTINE DSYEV_64( JOBZ, UPLO, N, A, LDA, W, WORK, LDWORK, INFO)
CHARACTER * 1 JOBZ, UPLO
INTEGER*8 N, LDA, LDWORK, INFO
DOUBLE PRECISION A(LDA,*), W(*), WORK(*)
SUBROUTINE SYEV( JOBZ, UPLO, N, A, [LDA], W, [WORK], [LDWORK], [INFO])
CHARACTER(LEN=1) :: JOBZ, UPLO
INTEGER :: N, LDA, LDWORK, INFO
REAL(8), DIMENSION(:) :: W, WORK
REAL(8), DIMENSION(:,:) :: A
SUBROUTINE SYEV_64( JOBZ, UPLO, N, A, [LDA], W, [WORK], [LDWORK],
* [INFO])
CHARACTER(LEN=1) :: JOBZ, UPLO
INTEGER(8) :: N, LDA, LDWORK, INFO
REAL(8), DIMENSION(:) :: W, WORK
REAL(8), DIMENSION(:,:) :: A
#include <sunperf.h>
void dsyev(char jobz, char uplo, int n, double *a, int lda, double *w, int *info);
void dsyev_64(char jobz, char uplo, long n, double *a, long lda, double *w, long *info);
dsyev computes all eigenvalues and, optionally, eigenvectors of a
real symmetric matrix A.
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* JOBZ (input)
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* UPLO (input)
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* N (input)
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The order of the matrix A. N >= 0.
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* A (input/output)
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On entry, the symmetric matrix A. If UPLO = 'U', the
leading N-by-N upper triangular part of A contains the
upper triangular part of the matrix A. If UPLO = 'L',
the leading N-by-N lower triangular part of A contains
the lower triangular part of the matrix A.
On exit, if JOBZ = 'V', then if INFO = 0, A contains the
orthonormal eigenvectors of the matrix A.
If JOBZ = 'N', then on exit the lower triangle (if UPLO='L')
or the upper triangle (if UPLO='U') of A, including the
diagonal, is destroyed.
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* LDA (input)
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The leading dimension of the array A. LDA >= max(1,N).
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* W (output)
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If INFO = 0, the eigenvalues in ascending order.
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* WORK (workspace)
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On exit, if INFO = 0, WORK(1) returns the optimal LDWORK.
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* LDWORK (input)
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The length of the array WORK. LDWORK >= max(1,3*N-1).
For optimal efficiency, LDWORK >= (NB+2)*N,
where NB is the blocksize for SSYTRD returned by ILAENV.
If LDWORK = -1, then a workspace query is assumed; the routine
only calculates the optimal size of the WORK array, returns
this value as the first entry of the WORK array, and no error
message related to LDWORK is issued by XERBLA.
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* INFO (output)
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