Ejemplo n.º 1
0
void
mag_sqrt(mag_t y, const mag_t x)
{
    if (mag_is_special(x))
    {
        mag_set(y, x);
    }
    else
    {
        double t;
        fmpz e;

        t = MAG_MAN(x) * ldexp(1.0, -MAG_BITS);
        e = MAG_EXP(x);

        if (!COEFF_IS_MPZ(e))
        {
            if (e % 2 != 0)
            {
                e = (e - 1) >> 1;
                t *= 2.0;
            }
            else
            {
                e >>= 1;
            }
            t = sqrt(t) * (1 + 1e-13);
            mag_set_d_2exp_fmpz(y, t, &e);
        }
Ejemplo n.º 2
0
static __inline__ void
_arb_poly_addmullow_rad(arb_ptr z, fmpz * zz,
                        const fmpz * xz, const double * xdbl, const fmpz * xexps,
                        const slong * xblocks, slong xlen,
                        const fmpz * yz, const double * ydbl, const fmpz * yexps,
                        const slong * yblocks, slong ylen, slong n)
{
    slong i, j, k, ii, xp, yp, xl, yl, bn;
    fmpz_t zexp;
    mag_t t;

    fmpz_init(zexp);
    mag_init(t);

    for (i = 0; (xp = xblocks[i]) != xlen; i++)
    {
        for (j = 0; (yp = yblocks[j]) != ylen; j++)
        {
            if (xp + yp >= n)
                continue;

            xl = xblocks[i + 1] - xp;
            yl = yblocks[j + 1] - yp;
            bn = FLINT_MIN(xl + yl - 1, n - xp - yp);
            xl = FLINT_MIN(xl, bn);
            yl = FLINT_MIN(yl, bn);

            fmpz_add_inline(zexp, xexps + i, yexps + j);

            if (xl > 1 && yl > 1 &&
                    (xl < DOUBLE_BLOCK_MAX_LENGTH || yl < DOUBLE_BLOCK_MAX_LENGTH))
            {
                fmpz_add_ui(zexp, zexp, 2 * DOUBLE_BLOCK_SHIFT);

                for (k = 0; k < bn; k++)
                {
                    /* Classical multiplication (may round down!) */
                    double ss = 0.0;

                    for (ii = FLINT_MAX(0, k - yl + 1);
                            ii <= FLINT_MIN(xl - 1, k); ii++)
                    {
                        ss += xdbl[xp + ii] * ydbl[yp + k - ii];
                    }

                    /* Compensate for rounding error */
                    ss *= DOUBLE_ROUNDING_FACTOR;

                    mag_set_d_2exp_fmpz(t, ss, zexp);
                    mag_add(arb_radref(z + xp + yp + k),
                            arb_radref(z + xp + yp + k), t);
                }
            }
            else
            {
                if (xl >= yl)
                    _fmpz_poly_mullow(zz, xz + xp, xl, yz + yp, yl, bn);
                else
                    _fmpz_poly_mullow(zz, yz + yp, yl, xz + xp, xl, bn);

                for (k = 0; k < bn; k++)
                {
                    mag_set_fmpz_2exp_fmpz(t, zz + k, zexp);
                    mag_add(arb_radref(z + xp + yp + k),
                            arb_radref(z + xp + yp + k), t);
                }
            }
        }
    }

    fmpz_clear(zexp);
    mag_clear(t);
}
Ejemplo n.º 3
0
int main()
{
    slong iter;
    flint_rand_t state;

    flint_printf("set_d_2exp_fmpz....");
    fflush(stdout);

    flint_randinit(state);

    for (iter = 0; iter < 100000 * arb_test_multiplier(); iter++)
    {
        fmpr_t a, b, c;
        fmpz_t e;
        mag_t m;
        double x;

        fmpr_init(a);
        fmpr_init(b);
        fmpr_init(c);
        fmpz_init(e);
        mag_init(m);

        x = d_randtest2(state);
        x = ldexp(x, 100 - n_randint(state, 200));

        if (n_randint(state, 100) == 0)
            x = 0.0;

        fmpz_randtest(e, state, 10);

        fmpr_set_d(a, x);
        fmpr_mul_2exp_fmpz(a, a, e);

        mag_set_d_2exp_fmpz(m, x, e);

        mag_get_fmpr(b, m);

        fmpr_set(c, a);
        fmpr_mul_ui(c, c, 1025, MAG_BITS, FMPR_RND_UP);
        fmpr_mul_2exp_si(c, c, -10);

        MAG_CHECK_BITS(m)

        if (!(fmpr_cmpabs(a, b) <= 0 && fmpr_cmpabs(b, c) <= 0))
        {
            flint_printf("FAIL\n\n");
            flint_printf("a = "); fmpr_print(a); flint_printf("\n\n");
            flint_printf("b = "); fmpr_print(b); flint_printf("\n\n");
            flint_printf("c = "); fmpr_print(c); flint_printf("\n\n");
            abort();
        }

        fmpr_clear(a);
        fmpr_clear(b);
        fmpr_clear(c);
        fmpz_clear(e);
        mag_clear(m);
    }

    flint_randclear(state);
    flint_cleanup();
    flint_printf("PASS\n");
    return EXIT_SUCCESS;
}