subroutine dcosqi (n,wsave) double precision wsave(1), dt, fk, pih data pih / 1.570796326 7948966192 3132169163 975 d0 / c dt = pih/dfloat(n) fk = 0.d0 do 101 k=1,n fk = fk+1.d0 wsave(k) = dcos(fk*dt) 101 continue c call drffti (n,wsave(n+1)) c return end