Exemple #1
0
void
nmod_poly_exp_series_monomial_ui(nmod_poly_t res, mp_limb_t coeff,
                                    ulong power, slong n)
{
    if (n == 0)
    {
        nmod_poly_zero(res);
        return;
    }

    if (coeff == UWORD(0))
    {
        nmod_poly_fit_length(res, 1);
        res->coeffs[0] = UWORD(1);
        res->length = 1;
        return;
    }

    if (power == 0)
    {
        flint_printf("Exception (nmod_poly_exp_series_monomial_ui). \n"
               "Constant term != 0.\n");
        abort();
    }

    if (coeff != UWORD(1))
        coeff = n_mod2_preinv(coeff, res->mod.n, res->mod.ninv);

    if (n == 1 || power >= n)
    {
        nmod_poly_fit_length(res, 1);
        res->coeffs[0] = UWORD(1);
        res->length = 1;
    }

    nmod_poly_fit_length(res, n);
    _nmod_poly_exp_series_monomial_ui(res->coeffs, coeff, power, n, res->mod);
    res->length = n;
    _nmod_poly_normalise(res);
}
Exemple #2
0
void
nmod_poly_exp_series(nmod_poly_t f, const nmod_poly_t h, long n)
{
    mp_ptr f_coeffs, h_coeffs;
    nmod_poly_t t1;
    long hlen, k;

    nmod_poly_fit_length(f, n);
    hlen = h->length;

    if (hlen > 0 && h->coeffs[0] != 0UL)
    {
        printf("Exception: nmod_poly_exp_series: constant term != 0\n");
        abort();
    }

    if (n <= 1 || hlen == 0)
    {
        if (n == 0)
        {
            nmod_poly_zero(f);
        }
        else
        {
            f->coeffs[0] = 1UL;
            f->length = 1;
        }
        return;
    }

    /* Handle monomials */
    for (k = 0; h->coeffs[k] == 0UL && k < n - 1; k++);
    if (k == hlen - 1 || k == n - 1)
    {
        hlen = FLINT_MIN(hlen, n);
        _nmod_poly_exp_series_monomial_ui(f->coeffs,
            h->coeffs[hlen-1], hlen - 1, n, f->mod);
        f->length = n;
        _nmod_poly_normalise(f);
        return;
    }

    if (n < NMOD_NEWTON_EXP_CUTOFF2)
    {
        _nmod_poly_exp_series_basecase(f->coeffs, h->coeffs, hlen, n, f->mod);
        f->length = n;
        _nmod_poly_normalise(f);
        return;
    }

    if (hlen < n)
    {
        h_coeffs = _nmod_vec_init(n);
        mpn_copyi(h_coeffs, h->coeffs, hlen);
        mpn_zero(h_coeffs + hlen, n - hlen);
    }
    else
        h_coeffs = h->coeffs;

    if (h == f && hlen >= n)
    {
        nmod_poly_init2(t1, h->mod.n, n);
        f_coeffs = t1->coeffs;
    }
    else
    {
        nmod_poly_fit_length(f, n);
        f_coeffs = f->coeffs;
    }

    _nmod_poly_exp_series(f_coeffs, h_coeffs, n, f->mod);

    if (h == f && hlen >= n)
    {
        nmod_poly_swap(f, t1);
        nmod_poly_clear(t1);
    }
    
    f->length = n;

    if (hlen < n)
        _nmod_vec_free(h_coeffs);

    _nmod_poly_normalise(f);
}