_CORTH(3F)_CORTH(3F)NAME
CORTH, SCORTH - 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 unitary similarity transformations.
SYNOPSYS
subroutine corth(nm, n, low, igh, ar, ai, ortr, orti)
integer nm, n, low, igh
double precision ar(nm,n), ai(nm,n), ortr(igh), orti(igh)
subroutine scorth(nm, n, low, igh, ar, ai, ortr, orti)
integer nm, n, low, igh
real ar(nm,n), ai(nm,n), ortr(igh), orti(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. Information about the unitary transformations used in
the reduction is stored in the remaining triangles under the Hessenberg
matrix.
ORTR and ORTI contain further information about the transformations.
Only elements LOW through IGH are used. Calls PYTHAG(A,B) for sqrt(A**2
+ B**2). Questions and comments should be directed to B. S. Garbow,
APPLIED MATHEMATICS DIVISION, ARGONNE NATIONAL LABORATORY
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