CTRCO(3F)

NAME
     CTRCO   - CTRCO estimates the condition of a complex triangular matrix.


SYNOPSYS
      SUBROUTINE CTRCO(T,LDT,N,RCOND,Z,JOB)

DESCRIPTION
     On Entry

     T COMPLEX(LDT,N)
        T contains the triangular matrix.  The zero
        elements of the matrix are not referenced, and
        the corresponding elements of the array can be
        used to store other information.

     LDT INTEGER
        LDT is the leading dimension of the array T.

     N INTEGER
        N is the order of the system.

     JOB INTEGER
        = 0         T  is lower triangular.
        = nonzero   T  is upper triangular.  On Return

     RCOND REAL
        an estimate of the reciprocal condition of  T .
        For the system  T*X = B , relative perturbations
        in  T  and  B  of size  EPSILON  may cause
        relative perturbations in  X  of size  EPSILON/RCOND .
        If  RCOND  is so small that the logical expression
        1.0 + RCOND .EQ. 1.0
        is true, then  T  may be singular to working
        precision.  In particular,  RCOND  is zero  if
        exact singularity is detected or the estimate
        underflows.

     Z COMPLEX(N)
        a work vector whose contents are usually unimportant.
        If  T  is close to a singular matrix, then  Z  is
        an approximate null vector in the sense that
        NORM(A*Z) = RCOND*NORM(A)*NORM(Z) .  LINPACK.  This version dated
     08/14/78 .  Cleve Moler, University of New Mexico, Argonne National Lab.
     Subroutines and Functions BLAS CAXPY,CSSCAL,SCASUM Fortran
     ABS,AIMAG,AMAX1,CMPLX,CONJG,REAL