CGECO(3F)							     CGECO(3F)

NAME    [Toc]    [Back]

     CGECO   - CGECO factors a complex matrix by Gaussian elimination and
     estimates the condition of	the matrix.

     If	 RCOND	is not needed, CGEFA is	slightly faster.  To solve  A*X	= B ,
     follow CGECO By CGESL.  To	Compute	 INVERSE(A)*C ,	follow CGECO by	CGESL.
     To	compute	 DETERMINANT(A)	, follow CGECO by CGEDI.  To compute
     INVERSE(A)	, follow CGECO by CGEDI.

SYNOPSYS    [Toc]    [Back]

      SUBROUTINE CGECO(A,LDA,N,IPVT,RCOND,Z)

DESCRIPTION    [Toc]    [Back]

     On	Entry

     A COMPLEX(LDA, N)
	the matrix to be factored.

     LDA INTEGER
	the leading dimension of the array  A .

     N INTEGER
	the order of the matrix	 A .  On Return

     A an upper	triangular matrix and the multipliers
	which were used	to obtain it.
	The factorization can be written  A = L*U  where
	L  is a	product	of permutation and unit	lower
	triangular matrices and	 U  is upper triangular.

     IPVT INTEGER(N)
	an integer vector of pivot indices.

     RCOND REAL
	an estimate of the reciprocal condition	of  A .
	For the	system	A*X = B	, relative perturbations
	in  A  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  A  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  A  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.



									Page 1






CGECO(3F)							     CGECO(3F)



     Subroutines and Functions LINPACK CGEFA BLAS CAXPY,CDOTC,CSSCAL,SCASUM
     Fortran ABS,AIMAG,AMAX1,CMPLX,CONJG,REAL


									PPPPaaaaggggeeee 2222