mirror of
https://github.com/vale981/arb
synced 2025-03-05 09:21:38 -05:00
88 lines
2.1 KiB
C
88 lines
2.1 KiB
C
/*
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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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/* assume np >= 2 * n - 1 */
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void
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acb_dft_convol_pad(acb_ptr fp, acb_ptr gp, acb_srcptr f, acb_srcptr g, slong n, slong np)
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{
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slong k;
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if (np < 2 * n - 1)
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{
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flint_printf("dft_convol_pad: overlapping padding %wd < 2*%wd-1\n", np, n);
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abort();
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}
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for (k = 0; k < n; k++)
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acb_set(gp + k, g + k);
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for (; k < np; k++)
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acb_zero(gp + k);
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for (k = 0; k < n; k++)
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acb_set(fp + k, f + k);
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for (k = 1; k < n; k++)
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acb_set(fp + np - k, f + n - k);
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for (k = n; k <= np - n; k++)
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acb_zero(fp + k);
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}
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void
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acb_dft_convol_rad2_precomp(acb_ptr w, acb_srcptr f, acb_srcptr g, slong len, const acb_dft_rad2_t rad2, slong prec)
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{
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slong np;
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acb_ptr fp, gp;
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np = rad2->n;
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if (len <= 0)
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return;
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fp = _acb_vec_init(np);
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gp = _acb_vec_init(np);
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if (len == np)
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{
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_acb_vec_set(fp, f, len);
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_acb_vec_set(gp, g, len);
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}
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else
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acb_dft_convol_pad(fp, gp, f, g, len, np);
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acb_dft_rad2_precomp_inplace(fp, rad2, prec);
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acb_dft_rad2_precomp_inplace(gp, rad2, prec);
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_acb_vec_kronecker_mul(gp, gp, fp, np, prec);
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acb_dft_inverse_rad2_precomp_inplace(gp, rad2, prec);
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_acb_vec_set(w, gp, len);
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_acb_vec_clear(fp, np);
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_acb_vec_clear(gp, np);
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}
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void
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acb_dft_convol_rad2(acb_ptr w, acb_srcptr f, acb_srcptr g, slong len, slong prec)
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{
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int e;
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acb_dft_rad2_t dft;
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/* catch power of 2 */
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if (len <= 0)
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return;
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else if ((len & (len - 1)) == 0)
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e = n_clog(len, 2);
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else
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e = n_clog(2 * len - 1, 2);
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acb_dft_rad2_init(dft, e, prec);
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acb_dft_convol_rad2_precomp(w, f, g, len, dft, prec);
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acb_dft_rad2_clear(dft);
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}
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