subroutine dhzero(nn,kj,x,y,d,ws)
c
integer nn,kj
double precision x(*),y(*),d(*),ws(*)
c
c this routine preconditions the cg - iteration
c by multipying with an approximation to the
c inverse of the capacitance matrix.
c
c x is input vector. x is not changed.
c y is output vector. ie y=h0*x .
c d is a diagonal matrix of dimension nn needed to define h0.
c kj and ws are dummy parameters in this version of dhzero.
c
c local.
c
integer i
c
do 10 i=1,nn
y(i)=d(i)*x(i)
10 continue
return
end