9integer,
intent(in) :: n
10real(8),
intent(in) :: wc(12,n),f(n)
11real(8),
intent(out) :: df(n)
15f1=f(1); f2=f(2); f3=f(3); f4=f(4)
16df(1)=wc(1,1)*f1+wc(2,1)*f2+wc(3,1)*f3+wc(4,1)*f4
17df(2)=wc(1,2)*f1+wc(2,2)*f2+wc(3,2)*f3+wc(4,2)*f4
20 f1=f(i-1); f2=f(i); f3=f(i+1); f4=f(i+2)
21 df(i)=wc(1,i)*f1+wc(2,i)*f2+wc(3,i)*f3+wc(4,i)*f4
24df(i)=wc(1,i)*f1+wc(2,i)*f2+wc(3,i)*f3+wc(4,i)*f4
25df(n)=wc(1,n)*f1+wc(2,n)*f2+wc(3,n)*f3+wc(4,n)*f4