/*=============================================================================

    This file is part of FLINT.

    FLINT is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    FLINT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with FLINT; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA

=============================================================================*/
/******************************************************************************

    Copyright (C) 2009 William Hart

******************************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <gmp.h>
#include "flint.h"
#include "ulong_extras.h"
#include "fmpz.h"

int
main(void)
{
    int i, result;
    FLINT_TEST_INIT(state);

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

    

    /* Test aliasing of d and f, a and g */
    for (i = 0; i < 1000 * flint_test_multiplier(); i++)
    {
        fmpz_t d, a, f, g, F, G;

        fmpz_init(d);
        fmpz_init(a);
        fmpz_init(f);
        fmpz_init(g);
        fmpz_init(F);
        fmpz_init(G);

        fmpz_randtest_unsigned(G, state, 200);
        fmpz_add_ui(G, G, 1);
        fmpz_randm(F, state, G);
        fmpz_set(f, F);
        fmpz_set(g, G);

        fmpz_gcdinv(d, a, f, g);
        fmpz_gcdinv(f, g, f, g);

        result = (fmpz_equal(d, f) && (fmpz_equal(a, g) || fmpz_is_zero(F)));
        if (!result)
        {
            flint_printf("FAIL:\n\n");
            flint_printf("d = "), fmpz_print(d), flint_printf("\n");
            flint_printf("a = "), fmpz_print(a), flint_printf("\n");
            flint_printf("f = "), fmpz_print(f), flint_printf("\n");
            flint_printf("g = "), fmpz_print(g), flint_printf("\n");
            flint_printf("F = "), fmpz_print(F), flint_printf("\n");
            flint_printf("G = "), fmpz_print(G), flint_printf("\n");
            abort();
        }

        fmpz_clear(d);
        fmpz_clear(a);
        fmpz_clear(f);
        fmpz_clear(g);
        fmpz_clear(F);
        fmpz_clear(G);
    }

    /* Test aliasing of a and f, d and g */
    for (i = 0; i < 1000 * flint_test_multiplier(); i++)
    {
        fmpz_t d, a, f, g, F, G;

        fmpz_init(d);
        fmpz_init(a);
        fmpz_init(f);
        fmpz_init(g);
        fmpz_init(F);
        fmpz_init(G);

        fmpz_randtest_unsigned(G, state, 200);
        fmpz_add_ui(G, G, 1);
        fmpz_randm(F, state, G);
        fmpz_set(f, F);
        fmpz_set(g, G);

        fmpz_gcdinv(d, a, f, g);
        fmpz_gcdinv(g, f, f, g);

        result = (fmpz_equal(d, g) && (fmpz_equal(a, f) || fmpz_is_zero(F)));
        if (!result)
        {
            flint_printf("FAIL:\n\n");
            flint_printf("d = "), fmpz_print(d), flint_printf("\n");
            flint_printf("a = "), fmpz_print(a), flint_printf("\n");
            flint_printf("f = "), fmpz_print(f), flint_printf("\n");
            flint_printf("g = "), fmpz_print(g), flint_printf("\n");
            flint_printf("F = "), fmpz_print(F), flint_printf("\n");
            flint_printf("G = "), fmpz_print(G), flint_printf("\n");
            abort();
        }

        fmpz_clear(d);
        fmpz_clear(a);
        fmpz_clear(f);
        fmpz_clear(g);
        fmpz_clear(F);
        fmpz_clear(G);
    }

    /* Test a f == d mod g (generically d == 1) */
    for (i = 0; i < 1000 * flint_test_multiplier(); i++)
    {
        fmpz_t d, a, f, g, t;

        fmpz_init(d);
        fmpz_init(a);
        fmpz_init(f);
        fmpz_init(g);
        fmpz_init(t);

        fmpz_randtest_unsigned(g, state, 200);
        fmpz_add_ui(g, g, 1);
        fmpz_randm(f, state, g);

        fmpz_gcdinv(d, a, f, g);

        fmpz_mul(t, a, f);
        fmpz_mod(t, t, g);

        result = (fmpz_equal(t, d) || fmpz_is_zero(f));
        if (!result)
        {
            flint_printf("FAIL:\n\n");
            flint_printf("d = "), fmpz_print(d), flint_printf("\n");
            flint_printf("a = "), fmpz_print(a), flint_printf("\n");
            flint_printf("f = "), fmpz_print(f), flint_printf("\n");
            flint_printf("g = "), fmpz_print(g), flint_printf("\n");
            flint_printf("t = "), fmpz_print(t), flint_printf("\n");
            abort();
        }

        fmpz_clear(d);
        fmpz_clear(a);
        fmpz_clear(f);
        fmpz_clear(g);
        fmpz_clear(t);
    }

    /* Test a f == d mod g (specifically d > 1) */
    for (i = 0; i < 1000 * flint_test_multiplier(); i++)
    {
        fmpz_t d, a, f, g, t, x;

        fmpz_init(d);
        fmpz_init(a);
        fmpz_init(f);
        fmpz_init(g);
        fmpz_init(t);
        fmpz_init(x);

        fmpz_randtest_unsigned(g, state, 200);
        fmpz_add_ui(g, g, 1);
        fmpz_randm(f, state, g);
        fmpz_randtest_unsigned(x, state, 100);
        fmpz_add_ui(x, x, 1);
        fmpz_mul(f, f, x);
        fmpz_mul(g, g, x);

        fmpz_gcdinv(d, a, f, g);

        fmpz_mul(t, a, f);
        fmpz_mod(t, t, g);

        result = (fmpz_equal(t, d) || fmpz_is_zero(f));
        if (!result)
        {
            flint_printf("FAIL:\n\n");
            flint_printf("d = "), fmpz_print(d), flint_printf("\n");
            flint_printf("a = "), fmpz_print(a), flint_printf("\n");
            flint_printf("f = "), fmpz_print(f), flint_printf("\n");
            flint_printf("g = "), fmpz_print(g), flint_printf("\n");
            flint_printf("t = "), fmpz_print(t), flint_printf("\n");
            flint_printf("x = "), fmpz_print(x), flint_printf("\n");
            abort();
        }

        fmpz_clear(d);
        fmpz_clear(a);
        fmpz_clear(f);
        fmpz_clear(g);
        fmpz_clear(t);
        fmpz_clear(x);
    }

    FLINT_TEST_CLEANUP(state);
    
    flint_printf("PASS\n");
    return 0;
}