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desclu
C DESCLU    SOURCE    CHAT      05/01/12    22:43:21     5004
CCC
C Descomposicion LU
CCC
      SUBROUTINE DESCLU (A,N)
      IMPLICIT INTEGER(I-N)
      integer n,i,j,k
      real*8    A(n,n),aux
      do k=1,n-1
          a(1,k+1)=a(1,k+1)/a(1,1)
          do i=2,k
              aux=0.D0
              do j=1,i-1
                  aux=aux+a(i,j)*a(j,k+1)
              enddo
              a(i,k+1)=(a(i,k+1)-aux)/a(i,i)
          enddo
          do i=2,k+1
              aux=0.D0
              do j=1,i-1
                  aux=aux+a(k+1,j)*a(j,i)
              enddo
              a(k+1,i)=a(k+1,i)-aux
          enddo
      enddo
      return
      end