?? fft4f2dt.f
字號:
! test of fft4f2d.f! program main integer nmax, nmaxsqrt parameter (nmax = 1024) parameter (nmaxsqrt = 32) integer ip(0 : nmaxsqrt + 1), n1, n2, i real*8 a(0 : nmax - 1, 0 : nmax - 1), & t(0 : nmax - 1, 0 : nmax - 1), w(0 : nmax * 3 / 2 - 1), & err, errorcheck2d! write (*, *) 'data length n1=? (n1 = power of 2) ' read (*, *) n1 write (*, *) 'data length n2=? (n2 = power of 2) ' read (*, *) n2 ip(0) = 0!! check of CDFT call putdata2d(nmax, n1, n2, a) call cdft2d(nmax, n1, n2, 1, a, ip, w) call cdft2d(nmax, n1, n2, -1, a, ip, w) err = errorcheck2d(nmax, n1, n2, 2.0d0 / n1 / n2, a) write (*, *) 'cdft2d err= ', err!! check of RDFT call putdata2d(nmax, n1, n2, a) call rdft2d(nmax, n1, n2, 1, a, ip, w) call rdft2d(nmax, n1, n2, -1, a, ip, w) err = errorcheck2d(nmax, n1, n2, 2.0d0 / n1 / n2, a) write (*, *) 'rdft2d err= ', err!! check of DDCT call putdata2d(nmax, n1, n2, a) call ddct2d(nmax, n1, n2, 1, a, t, ip, w) call ddct2d(nmax, n1, n2, -1, a, t, ip, w) do i = 0, n1 - 1 a(i, 0) = a(i, 0) * 0.5d0 end do do i = 0, n2 - 1 a(0, i) = a(0, i) * 0.5d0 end do err = errorcheck2d(nmax, n1, n2, 4.0d0 / n1 / n2, a) write (*, *) 'ddct2d err= ', err!! check of DDST call putdata2d(nmax, n1, n2, a) call ddst2d(nmax, n1, n2, 1, a, t, ip, w) call ddst2d(nmax, n1, n2, -1, a, t, ip, w) do i = 0, n1 - 1 a(i, 0) = a(i, 0) * 0.5d0 end do do i = 0, n2 - 1 a(0, i) = a(0, i) * 0.5d0 end do err = errorcheck2d(nmax, n1, n2, 4.0d0 / n1 / n2, a) write (*, *) 'ddst2d err= ', err! end!! subroutine putdata2d(n1max, n1, n2, a) integer n1max, n1, n2, j1, j2, seed real*8 a(0 : n1max - 1, 0 : *), drnd seed = 0 do j2 = 0, n2 - 1 do j1 = 0, n1 - 1 a(j1, j2) = drnd(seed) end do end do end!! function errorcheck2d(n1max, n1, n2, scale, a) integer n1max, n1, n2, j1, j2, seed real*8 scale, a(0 : n1max - 1, 0 : *), drnd, err, e, & errorcheck2d err = 0 seed = 0 do j2 = 0, n2 - 1 do j1 = 0, n1 - 1 e = drnd(seed) - a(j1, j2) * scale err = max(err, abs(e)) end do end do errorcheck2d = err end!!! random number generator, 0 <= drnd < 1 real*8 function drnd(seed) integer seed seed = mod(seed * 7141 + 54773, 259200) drnd = seed * (1.0d0 / 259200) end!
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