 
      SUBROUTINE SGECO(A,LDA,N,IPVT,RCOND,Z)
C***BEGIN PROLOGUE  SGECO
C***DATE WRITTEN   780814   (YYMMDD)
C***REVISION DATE  820801   (YYMMDD)
C***CATEGORY NO.  D2A1
C***KEYWORDS  CONDITION,FACTOR,LINEAR ALGEBRA,LINPACK,MATRIX
C***AUTHOR  MOLER, C. B., (U. OF NEW MEXICO)
C***PURPOSE  Factors a real matrix by Gaussian elimination and estimates
C            the condition number of the matrix.
C***DESCRIPTION
C
C     SGECO factors a real matrix by Gaussian elimination
C     and estimates the condition of the matrix.
C
C     If  RCOND  is not needed, SGEFA is slightly faster.
C     To solve  A*X = B , follow SGECO by SGESL.
C     To compute  INVERSE(A)*C , follow SGECO by SGESL.
C     To compute  DETERMINANT(A) , follow SGECO by SGEDI.
C     To compute  INVERSE(A) , follow SGECO by SGEDI.
C
C     On Entry
C
C        A       REAL(LDA, N)
C                the matrix to be factored.
C
C        LDA     INTEGER
C                the leading dimension of the array  A .
C
C        N       INTEGER
C                the order of the matrix  A .
C
C     On Return
C
C        A       an upper triangular matrix and the multipliers
C                which were used to obtain it.
C                The factorization can be written  A = L*U , where
C                L  is a product of permutation and unit lower
C                triangular matrices and  U  is upper triangular.
C
C        IPVT    INTEGER(N)
C                an integer vector of pivot indices.
C
C        RCOND   REAL
C                an estimate of the reciprocal condition of  A .
C                For the system  A*X = B , relative perturbations
C                in  A  and  B  of size  EPSILON  may cause
C                relative perturbations in  X  of size  EPSILON/RCOND .
C                If  RCOND  is so small that the logical expression
C                           1.0 + RCOND .EQ. 1.0
C                is true, then  A  may be singular to working
C                precision.  In particular,  RCOND  is zero  if
C                exact singularity is detected or the estimate
C                underflows.
C
C        Z       REAL(N)
C                a work vector whose contents are usually unimportant.
C                If  A  is close to a singular matrix, then  Z  is
C                an approximate null vector in the sense that
C                NORM(A*Z) = RCOND*NORM(A)*NORM(Z) .
C
C     LINPACK.  This version dated 08/14/78 .
C     Cleve Moler, University of New Mexico, Argonne National Lab.
C
C     Subroutines and Functions
C
C     LINPACK SGEFA
C     BLAS SAXPY,SDOT,SSCAL,SASUM
C     Fortran ABS,AMAX1,SIGN
C***REFERENCES  DONGARRA J.J., BUNCH J.R., MOLER C.B., STEWART G.W.,
C                 *LINPACK USERS  GUIDE*, SIAM, 1979.
C***ROUTINES CALLED  SASUM,SAXPY,SDOT,SGEFA,SSCAL
C***END PROLOGUE  SGECO
 
 
