_COMHES(3F)_COMHES(3F)NAME
COMHES, SCOMHES - EISPACK routine. Given a COMPLEX GENERAL matrix,
this subroutine reduces a submatrix situated in rows and columns LOW
through IGH to upper Hessenberg form by stabilized elementary similarity
transformations.
SYNOPSYS
subroutine comhes(nm, n, low, igh, ar, ai, int)
integer nm, n, low, igh
double precision ar(nm,n), ai(nm,n)
integer int(igh)
subroutine scomhes(nm, n, low, igh, ar, ai, int)
integer nm, n, low, igh
real ar(nm,n), ai(nm,n)
integer int(igh)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.
AR and AI contain the real and imaginary parts, respectively, of the
complex input matrix. On OUTPUT
AR and AI contain the real and imaginary parts, respectively, of the
Hessenberg matrix. The multipliers which were used in the reduction are
stored in the remaining triangles under the Hessenberg matrix.
INT contains information on the rows and columns interchanged in the
reduction. Only elements LOW through IGH are used. 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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