sgeev
sgeev - compute for an N-by-N real nonsymmetric matrix A, the eigenvalues and, optionally, the left and/or right eigenvectors
SUBROUTINE SGEEV( JOBVL, JOBVR, N, A, LDA, WR, WI, VL, LDVL, VR,
* LDVR, WORK, LDWORK, INFO)
CHARACTER * 1 JOBVL, JOBVR
INTEGER N, LDA, LDVL, LDVR, LDWORK, INFO
REAL A(LDA,*), WR(*), WI(*), VL(LDVL,*), VR(LDVR,*), WORK(*)
SUBROUTINE SGEEV_64( JOBVL, JOBVR, N, A, LDA, WR, WI, VL, LDVL, VR,
* LDVR, WORK, LDWORK, INFO)
CHARACTER * 1 JOBVL, JOBVR
INTEGER*8 N, LDA, LDVL, LDVR, LDWORK, INFO
REAL A(LDA,*), WR(*), WI(*), VL(LDVL,*), VR(LDVR,*), WORK(*)
SUBROUTINE GEEV( JOBVL, JOBVR, [N], A, [LDA], WR, WI, VL, [LDVL],
* VR, [LDVR], [WORK], [LDWORK], [INFO])
CHARACTER(LEN=1) :: JOBVL, JOBVR
INTEGER :: N, LDA, LDVL, LDVR, LDWORK, INFO
REAL, DIMENSION(:) :: WR, WI, WORK
REAL, DIMENSION(:,:) :: A, VL, VR
SUBROUTINE GEEV_64( JOBVL, JOBVR, [N], A, [LDA], WR, WI, VL, [LDVL],
* VR, [LDVR], [WORK], [LDWORK], [INFO])
CHARACTER(LEN=1) :: JOBVL, JOBVR
INTEGER(8) :: N, LDA, LDVL, LDVR, LDWORK, INFO
REAL, DIMENSION(:) :: WR, WI, WORK
REAL, DIMENSION(:,:) :: A, VL, VR
#include <sunperf.h>
void sgeev(char jobvl, char jobvr, int n, float *a, int lda, float *wr, float *wi, float *vl, int ldvl, float *vr, int ldvr, int *info);
void sgeev_64(char jobvl, char jobvr, long n, float *a, long lda, float *wr, float *wi, float *vl, long ldvl, float *vr, long ldvr, long *info);
sgeev computes for an N-by-N real nonsymmetric matrix A, the
eigenvalues and, optionally, the left and/or right eigenvectors.
The right eigenvector v(j) of A satisfies
A * v(j) = lambda(j) * v(j)
where lambda(j) is its eigenvalue.
The left eigenvector u(j) of A satisfies
u(j)**H * A = lambda(j) * u(j)**H
where u(j)**H denotes the conjugate transpose of u(j).
The computed eigenvectors are normalized to have Euclidean norm
equal to 1 and largest component real.
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* JOBVL (input)
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* JOBVR (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 N-by-N matrix A.
On exit, A has been overwritten.
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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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* WR (output)
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WR and WI contain the real and imaginary parts,
respectively, of the computed eigenvalues. Complex
conjugate pairs of eigenvalues appear consecutively
with the eigenvalue having the positive imaginary part
first.
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* WI (output)
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See the description for WR.
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* VL (output)
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If JOBVL = 'V', the left eigenvectors u(j) are stored one
after another in the columns of VL, in the same order
as their eigenvalues.
If JOBVL = 'N', VL is not referenced.
If the j-th eigenvalue is real, then u(j) = VL(:,j),
the j-th column of VL.
If the j-th and (j+1)-st eigenvalues form a complex
conjugate pair, then u(j) = VL(:,j) + i*VL(:,j+1) and
u(j+1) = VL(:,j) - i*VL(:,j+1).
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* LDVL (input)
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The leading dimension of the array VL. LDVL >= 1; if
JOBVL = 'V', LDVL >= N.
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* VR (input)
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If JOBVR = 'V', the right eigenvectors v(j) are stored one
after another in the columns of VR, in the same order
as their eigenvalues.
If JOBVR = 'N', VR is not referenced.
If the j-th eigenvalue is real, then v(j) = VR(:,j),
the j-th column of VR.
If the j-th and (j+1)-st eigenvalues form a complex
conjugate pair, then v(j) = VR(:,j) + i*VR(:,j+1) and
v(j+1) = VR(:,j) - i*VR(:,j+1).
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* LDVR (input)
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The leading dimension of the array VR. LDVR >= 1; if
JOBVR = 'V', LDVR >= N.
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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 dimension of the array WORK. LDWORK >= max(1,3*N), and
if JOBVL = 'V' or JOBVR = 'V', LDWORK >= 4*N. For good
performance, LDWORK must generally be larger.
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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