DGEFA(3F)

NAME
     DGEFA   - DGEFA factors a double precision matrix by Gaussian
     elimination.

     DGEFA is usually called by DGECO, but it can be called directly with a
     saving in time if  RCOND  is not needed.  (Time for DGECO) = (1 +
     9/N)*(Time for DGEFA) .


SYNOPSYS
      SUBROUTINE DGEFA(A,LDA,N,IPVT,INFO)

DESCRIPTION
     On Entry

     A DOUBLE PRECISION(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.

     INFO INTEGER
        = 0  normal value.
        = K  if  U(K,K) .EQ. 0.0 .  This is not an error
        condition for this subroutine, but it does
        indicate that DGESL or DGEDI will divide by zero
        if called.  Use  RCOND  in DGECO for a reliable
        indication of singularity.  LINPACK.  This version dated 08/14/78 .
     Cleve Moler, University of New Mexico, Argonne National Lab.  Subroutines
     and Functions BLAS DAXPY,DSCAL,IDAMAX