flint-sys 0.9.0

Bindings to the FLINT C library
Documentation 
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/*
    Copyright (C) 2024 Jean Kieffer

    This file is part of FLINT.

    FLINT is free software: you can redistribute it and/or modify it under
    the terms of the GNU Lesser General Public License (LGPL) as published
    by the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.  See <https://www.gnu.org/licenses/>.
*/

#include "arb.h"
#include "acb.h"
#include "arb_mat.h"
#include "acb_mat.h"
#include "acb_theta.h"

void
acb_theta_ctx_tau_dupl(acb_theta_ctx_tau_t ctx, slong prec)
{
    slong g = ctx->g;
    slong n = 1 << g;
    slong j, k;
    arb_t sqrt2;

    arb_init(sqrt2);
    arb_set_si(sqrt2, 2);
    arb_sqrt(sqrt2, sqrt2, prec);

    /* Update cho, yinv */
    arb_mat_scalar_mul_arb(&ctx->cho, &ctx->cho, sqrt2, prec);
    arb_mat_scalar_mul_2exp_si(&ctx->yinv, &ctx->yinv, -1);

    /* Swap matrices around */
    FLINT_SWAP(acb_mat_struct, *ctx->exp_tau_div_4, *ctx->exp_tau_div_2);
    FLINT_SWAP(acb_mat_struct, *ctx->exp_tau_div_2, *ctx->exp_tau);
    FLINT_SWAP(acb_mat_struct, *ctx->exp_tau_div_4_inv, *ctx->exp_tau_div_2_inv);
    FLINT_SWAP(acb_mat_struct, *ctx->exp_tau_div_2_inv, *ctx->exp_tau_inv);

    /* Update exp_tau and exp_tau_inv */
    for (j = 0; j < g; j++)
    {
        for (k = j; k < g; k++)
        {
            acb_sqr(acb_mat_entry(ctx->exp_tau, j, k),
                acb_mat_entry(ctx->exp_tau_div_2, j, k), prec);
            acb_sqr(acb_mat_entry(ctx->exp_tau_inv, j, k),
                acb_mat_entry(ctx->exp_tau_div_2_inv, j, k), prec);
        }
    }

    if (ctx->allow_shift)
    {
        /* Update exp_tau_a */
        for (j = 0; j < n * g; j++)
        {
            acb_sqr(&ctx->exp_tau_a[j], &ctx->exp_tau_a[j], prec);
            acb_sqr(&ctx->exp_tau_a_inv[j], &ctx->exp_tau_a_inv[j], prec);
        }
        /* Update exp_a_tau_a_div_4 */
        for (j = 0; j < n; j++)
        {
            acb_sqr(&ctx->exp_a_tau_a_div_4[j], &ctx->exp_a_tau_a_div_4[j], prec);
        }
    }

    arb_clear(sqrt2);
}