function dcsin(z1) double complex dcsin, z1, z2 double precision dummy(2), a, b, c, d equivalence (a,z2,dummy(1)), (b,dummy(2)) z2 = z1 c = dexp(b) d = 1.0d0/c b = dcos(a)*(c-d)/2.0d0 a = dsin(a)*(c+d)/2.0d0 dcsin = z2 return end