C ADDVEC    SOURCE    CHAT      05/01/12    21:17:50     5004           
CCC
C x_i = a_i + b * c_i
CCC
      SUBROUTINE ADDVEC (X,A,B,C,N)
      IMPLICIT INTEGER(I-N)
      integer i,n
      real*8 x(n),a(n),b,c(n)
      do i=1,n
       x(i)=a(i)+b*c(i)
      enddo
      return
      end