_COMLR(3F)_COMLR(3F)NAME
COMLR, SCOMLR - EISPACK routine. This subroutine finds the
eigenvalues of a COMPLEX UPPER Hessenberg matrix by the modified LR
method.
SYNOPSYS
subroutine comlr(nm, n, low, igh, hr, hi, wr, wi, ierr)
integer nm, n, low, igh, ierr
double precision hr(nm,n), hi(nm,n), wr(n), wi(n)
subroutine scomlr(nm, n, low, igh, hr, hi, wr, wi, ierr)
integer nm, n, low, igh, ierr
real hr(nm,n), hi(nm,n), wr(n), wi(n)DESCRIPTION
On INPUT
NM must be set to the row dimension of two-dimensional array parameters
as declared in the calling program dimension statement.
N is the order of the matrix.
LOW and IGH are integers determined by the balancing subroutine CBAL.
If CBAL has not been used, set LOW=1, IGH=N.
HR and HI contain the real and imaginary parts, respectively, of the
complex upper Hessenberg matrix. Their lower triangles below the
subdiagonal contain the multipliers which were used in the reduction by
COMHES, if performed. On OUTPUT The upper Hessenberg portions of HR and
HI have been destroyed. Therefore, they must be saved before calling
COMLR if subsequent calculation of eigenvectors is to be performed.
WR and WI contain the real and imaginary parts, respectively, of the
eigenvalues. If an error exit is made, the eigenvalues should be correct
for indices IERR+1,...,N.
IERR is set to Zero for normal return, J if the J-th
eigenvalue has not been
determined after a total of 30*N iterations. Calls CSROOT for complex
square root. Calls CDIV for complex division. Questions and comments
should be directed to B. S. Garbow, APPLIED MATHEMATICS DIVISION, ARGONNE
NATIONAL LABORATORY
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