mirror of
https://github.com/vale981/arb
synced 2025-03-06 01:41:39 -05:00
68 lines
1.8 KiB
C
68 lines
1.8 KiB
C
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/*
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Copyright (C) 2016 Pascal Molin
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This file is part of Arb.
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Arb is free software: you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License (LGPL) as published
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by the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version. See <http://www.gnu.org/licenses/>.
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*/
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#include "acb_dft.h"
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void
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acb_dft_bluestein_init(acb_dft_bluestein_t t, slong n, slong prec)
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{
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nmod_t n2;
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slong k, k2;
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acb_ptr z2n;
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int e = n_clog(2 * n - 1, 2);
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acb_dft_rad2_init(t->rad2, e, prec);
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z2n = _acb_vec_init(2 * n);
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_acb_vec_nth_roots(z2n, 2 * n, prec);
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nmod_init(&n2, 2 * n);
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t->n = n;
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t->z = _acb_vec_init(n);
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for (k = 0, k2 = 0; k < n; k++)
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{
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acb_conj(t->z + k, z2n + k2);
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k2 = nmod_add(k2, 2 * k + 1, n2);
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}
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_acb_vec_clear(z2n, 2 * n);
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}
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void
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acb_dft_bluestein_precomp(acb_ptr w, acb_srcptr v, const acb_dft_bluestein_t t, slong prec)
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{
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slong n = t->n;
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acb_ptr vz, wz, z;
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z = t->z;
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/* TODO: allocate directly length 2^e and pad */
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flint_printf("\n\n====================\n\nv\n");
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acb_vec_printd_index(v, n, 10);
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vz = _acb_vec_init(n);
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acb_vec_kronecker_mul_conj(vz, z, v, n, prec);
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flint_printf("\nvz\n");
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acb_vec_printd_index(vz, n, 10);
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wz = _acb_vec_init(n);
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acb_dft_convol_rad2_precomp(wz, vz, z, n, t->rad2, prec);
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flint_printf("\nwz\n");
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acb_vec_printd_index(wz, n, 10);
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acb_vec_kronecker_mul_conj(w, z, wz, n, prec);
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flint_printf("\nw\n");
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acb_vec_printd_index(w, n, 10);
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_acb_vec_clear(wz, n);
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_acb_vec_clear(vz, n);
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}
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void
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acb_dft_bluestein(acb_ptr w, acb_srcptr v, slong len, slong prec)
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{
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acb_dft_bluestein_t t;
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acb_dft_bluestein_init(t, len, prec);
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acb_dft_bluestein_precomp(w, v, t, prec);
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acb_dft_bluestein_clear(t);
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}
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