140 lines
3.9 KiB
C
140 lines
3.9 KiB
C
/*=============================================================================
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This file is part of FLINT.
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FLINT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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FLINT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with FLINT; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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=============================================================================*/
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/******************************************************************************
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Copyright (C) 2012 Fredrik Johansson
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******************************************************************************/
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#include <stdio.h>
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#include <stdlib.h>
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#include <gmp.h>
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#include "flint.h"
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#include "ulong_extras.h"
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#include "fmpz.h"
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int
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main(void)
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{
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slong iter;
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int result;
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FLINT_TEST_INIT(state);
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flint_printf("abs_ubound_ui_2exp....");
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fflush(stdout);
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for (iter = 0; iter < 10000 * flint_test_multiplier(); iter++)
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{
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fmpz_t x, y;
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slong bits, yexp;
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slong exp;
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mp_limb_t man;
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fmpz_init(x);
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fmpz_init(y);
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fmpz_randtest_not_zero(x, state, 1 + n_randint(state, 400));
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bits = 1 + n_randint(state, FLINT_BITS - 1);
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/* compute an exactly rounded mantissa */
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fmpz_abs(y, x);
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if (fmpz_is_zero(y))
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{
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yexp = 0;
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}
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else
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{
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yexp = fmpz_bits(y) - bits;
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if (yexp >= 0)
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{
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fmpz_cdiv_q_2exp(y, y, yexp);
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if (fmpz_bits(y) == bits + 1)
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{
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fmpz_tdiv_q_2exp(y, y, 1);
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yexp--;
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}
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}
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else
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{
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fmpz_mul_2exp(y, y, -yexp);
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}
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}
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man = fmpz_abs_ubound_ui_2exp(&exp, x, bits);
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if (FLINT_BIT_COUNT(man) != bits)
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{
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flint_printf("wrong number of bits!\n");
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flint_printf("bits = %wd, count = %u\n\n", bits, FLINT_BIT_COUNT(man));
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flint_printf("x = "); fmpz_print(x); flint_printf("\n\n");
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flint_printf("bits(x) = %wd\n\n", fmpz_bits(x));
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flint_printf("y = "); fmpz_print(y); flint_printf("\n\n");
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flint_printf("yexp = %wd\n\n", yexp);
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flint_printf("man = %wu, exp = %wd\n", man, exp);
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abort();
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}
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/* ok if equal */
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result = (fmpz_cmp_ui(y, man) == 0);
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/* ok if mantissa is 1 larger */
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if (!result)
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{
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result = ((exp == yexp) && (fmpz_cmp_ui(y, man - 1) == 0));
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}
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/* ok if the exact mantissa is 2^r-1 and overflow to 2^r happened */
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if (!result)
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{
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fmpz_t t;
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fmpz_init(t);
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fmpz_set_ui(t, man);
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fmpz_mul_ui(t, t, 2);
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fmpz_sub_ui(t, t, 1);
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result = (exp == yexp + 1) && fmpz_equal(t, y);
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fmpz_clear(t);
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}
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if (!result)
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{
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flint_printf("different from exact ceiling division\n");
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flint_printf("bits = %wd\n\n", bits);
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flint_printf("x = "); fmpz_print(x); flint_printf("\n\n");
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flint_printf("bits(x) = %wd\n\n", fmpz_bits(x));
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flint_printf("y = "); fmpz_print(y); flint_printf(", yexp = %wd\n\n", yexp);
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flint_printf("man = %wu, exp = %wd\n", man, exp);
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abort();
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}
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fmpz_clear(x);
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fmpz_clear(y);
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}
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FLINT_TEST_CLEANUP(state);
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flint_printf("PASS\n");
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return 0;
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}
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