C++ (Cpp) nmod_neg Examples

Example #1

File: det.c Project: goens/flint2

mp_limb_t
_nmod_mat_det(nmod_mat_t A)
{
    mp_limb_t det;
    long * P;

    long m = A->r;
    long rank;
    long i;

    P = flint_malloc(sizeof(long) * m);
    rank = nmod_mat_lu(P, A, 1);

    det = 0UL;

    if (rank == m)
    {
        det = 1UL;
        for (i = 0; i < m; i++)
            det = n_mulmod2_preinv(det, nmod_mat_entry(A, i, i),
                A->mod.n, A->mod.ninv);
    }

    if (_perm_parity(P, m) == 1)
        det = nmod_neg(det, A->mod);

    flint_free(P);
    return det;
}

Example #2

File: taylor_shift_convolution.c Project: clear731/lattice

void
_nmod_poly_taylor_shift_convolution(mp_ptr p, mp_limb_t c, slong len, nmod_t mod)
{
    slong i, n = len - 1;
    mp_limb_t f, d;
    mp_ptr t, u;

    if (c == 0 || len <= 1)
        return;

    t = _nmod_vec_init(len);
    u = _nmod_vec_init(len);

    f = 1;
    for (i = 2; i <= n; i++)
    {
        f = n_mulmod2_preinv(f, i, mod.n, mod.ninv);
        p[i] = n_mulmod2_preinv(p[i], f, mod.n, mod.ninv);
    }

    _nmod_poly_reverse(p, p, len, len);

    t[n] = 1;
    for (i = n; i > 0; i--)
        t[i - 1] = n_mulmod2_preinv(t[i], i, mod.n, mod.ninv);

    if (c == mod.n - 1)
    {
        for (i = 1; i <= n; i += 2)
            t[i] = nmod_neg(t[i], mod);
    }
    else if (c != 1)
    {
        d = c;

        for (i = 1; i <= n; i++)
        {
            t[i] = n_mulmod2_preinv(t[i], d, mod.n, mod.ninv);
            d = n_mulmod2_preinv(d, c, mod.n, mod.ninv);
        }
    }

    _nmod_poly_mullow(u, p, len, t, len, len, mod);

    f = n_mulmod2_preinv(f, f, mod.n, mod.ninv);
    f = n_invmod(f, mod.n);

    for (i = n; i >= 0; i--)
    {
        p[i] = n_mulmod2_preinv(u[n - i], f, mod.n, mod.ninv);
        f = n_mulmod2_preinv(f, (i == 0) ? 1 : i, mod.n, mod.ninv);
    }

    _nmod_vec_clear(t);
    _nmod_vec_clear(u);
}

Example #3

File: product_roots_nmod_vec.c Project: clear731/lattice

void
_nmod_poly_product_roots_nmod_vec(mp_ptr poly, mp_srcptr xs, slong n, nmod_t mod)
{
    if (n == 0)
    {
        poly[0] = UWORD(1);
    }
    else if (n < 20)
    {
        slong i, j;

        poly[n] = UWORD(1);
        poly[n - 1] = nmod_neg(xs[0], mod);

        for (i = 1; i < n; i++)
        {
            poly[n-i-1] = nmod_neg(n_mulmod2_preinv(poly[n-i], xs[i],
                mod.n, mod.ninv), mod);

            for (j = 0; j < i - 1; j++)
            {
                poly[n-i+j] = nmod_sub(poly[n-i+j],
                    n_mulmod2_preinv(poly[n-i+j+1], xs[i], mod.n, mod.ninv),
                        mod);
            }

            poly[n-1] = nmod_sub(poly[n-1], xs[i], mod);
        }
    }
    else
    {
        const slong m = (n + 1) / 2;
        mp_ptr tmp;

        tmp = _nmod_vec_init(n + 2);

        _nmod_poly_product_roots_nmod_vec(tmp, xs, m, mod);
        _nmod_poly_product_roots_nmod_vec(tmp + m + 1, xs + m, n - m, mod);
        _nmod_poly_mul(poly, tmp, m + 1, tmp + m + 1, n - m + 1, mod);

        _nmod_vec_clear(tmp);
    }
}

Example #4

File: lu_classical.c Project: fredrik-johansson/hmod_mat

long 
hmod_mat_lu_classical(long * P, hmod_mat_t A, int rank_check)
{
    hlimb_t d, e, **a;
    nmod_t mod;
    long i, m, n, rank, length, row, col;

    m = A->r;
    n = A->c;
    a = A->rows;
    mod = A->mod;

    rank = row = col = 0;

    for (i = 0; i < m; i++)
        P[i] = i;

    while (row < m && col < n)
    {
        if (hmod_mat_pivot(A, P, row, col) == 0)
        {
            if (rank_check)
                return 0;
            col++;
            continue;
        }

        rank++;

        d = a[row][col];
        d = n_invmod(d, mod.n);
        length = n - col - 1;

        for (i = row + 1; i < m; i++)
        {
            e = n_mulmod2_preinv(a[i][col], d, mod.n, mod.ninv);
            if (length != 0)
                _hmod_vec_scalar_addmul_hmod(a[i] + col + 1,
                    a[row] + col + 1, length, nmod_neg(e, mod), mod);

            a[i][col] = 0;
            a[i][rank - 1] = e;
        }
        row++;
        col++;
    }

    return rank;
}