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/*
Copyright (C) 2012 Fredrik Johansson
This file is part of Arb.
Arb is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version. See <http://www.gnu.org/licenses/>.
*/
#include "acb_mat.h"
int fmpq_mat_is_invertible(const fmpq_mat_t A)
{
int r;
fmpq_t t;
fmpq_init(t);
fmpq_mat_det(t, A);
r = !fmpq_is_zero(t);
fmpq_clear(t);
return r;
}
int main()
{
slong iter;
flint_rand_t state;
flint_printf("lu_recursive....");
fflush(stdout);
flint_randinit(state);
/* Dummy test with rectangular matrices. Rectangular matrices are
not actually supported (the output may be bogus), but the algorithm
should at least not crash. */
for (iter = 0; iter < 1000 * arb_test_multiplier(); iter++)
{
slong m, n, prec;
slong *perm;
acb_mat_t A, LU;
n = n_randint(state, 20);
m = n_randint(state, 20);
prec = 2 + n_randint(state, 200);
acb_mat_init(A, n, m);
acb_mat_init(LU, n, m);
perm = _perm_init(n);
acb_mat_randtest(A, state, prec, 10);
if (n_randint(state, 2))
{
acb_mat_lu_recursive(perm, LU, A, prec);
}
else
{
acb_mat_set(LU, A);
acb_mat_lu_recursive(perm, LU, LU, prec);
}
acb_mat_clear(A);
acb_mat_clear(LU);
_perm_clear(perm);
}
for (iter = 0; iter < 2000 * arb_test_multiplier(); iter++)
{
fmpq_mat_t Q;
acb_mat_t A, LU, P, L, U, T;
slong i, j, n, qbits, prec, *perm;
int q_invertible, r_invertible;
n = n_randint(state, 20);
qbits = 1 + n_randint(state, 100);
prec = 2 + n_randint(state, 202);
fmpq_mat_init(Q, n, n);
acb_mat_init(A, n, n);
acb_mat_init(LU, n, n);
acb_mat_init(P, n, n);
acb_mat_init(L, n, n);
acb_mat_init(U, n, n);
acb_mat_init(T, n, n);
perm = _perm_init(n);
fmpq_mat_randtest(Q, state, qbits);
q_invertible = fmpq_mat_is_invertible(Q);
if (!q_invertible)
{
acb_mat_set_fmpq_mat(A, Q, prec);
r_invertible = acb_mat_lu_recursive(perm, LU, A, prec);
if (r_invertible)
{
flint_printf("FAIL: matrix is singular over Q but not over R\n");
flint_printf("n = %wd, prec = %wd\n", n, prec);
flint_printf("\n");
flint_printf("Q = \n"); fmpq_mat_print(Q); flint_printf("\n\n");
flint_printf("A = \n"); acb_mat_printd(A, 15); flint_printf("\n\n");
flint_printf("LU = \n"); acb_mat_printd(LU, 15); flint_printf("\n\n");
}
}
else
{
/* now this must converge */
while (1)
{
acb_mat_set_fmpq_mat(A, Q, prec);
r_invertible = acb_mat_lu_recursive(perm, LU, A, prec);
if (r_invertible)
{
break;
}
else
{
if (prec > 10000)
{
flint_printf("FAIL: failed to converge at 10000 bits\n");
flint_abort();
}
prec *= 2;
}
}
acb_mat_one(L);
for (i = 0; i < n; i++)
for (j = 0; j < i; j++)
acb_set(acb_mat_entry(L, i, j),
acb_mat_entry(LU, i, j));
for (i = 0; i < n; i++)
for (j = i; j < n; j++)
acb_set(acb_mat_entry(U, i, j),
acb_mat_entry(LU, i, j));
for (i = 0; i < n; i++)
acb_one(acb_mat_entry(P, perm[i], i));
acb_mat_mul(T, P, L, prec);
acb_mat_mul(T, T, U, prec);
if (!acb_mat_contains_fmpq_mat(T, Q))
{
flint_printf("FAIL (containment, iter = %wd)\n", iter);
flint_printf("n = %wd, prec = %wd\n", n, prec);
flint_printf("\n");
flint_printf("Q = \n"); fmpq_mat_print(Q); flint_printf("\n\n");
flint_printf("A = \n"); acb_mat_printd(A, 15); flint_printf("\n\n");
flint_printf("LU = \n"); acb_mat_printd(LU, 15); flint_printf("\n\n");
flint_printf("L = \n"); acb_mat_printd(L, 15); flint_printf("\n\n");
flint_printf("U = \n"); acb_mat_printd(U, 15); flint_printf("\n\n");
flint_printf("P*L*U = \n"); acb_mat_printd(T, 15); flint_printf("\n\n");
flint_abort();
}
}
fmpq_mat_clear(Q);
acb_mat_clear(A);
acb_mat_clear(LU);
acb_mat_clear(P);
acb_mat_clear(L);
acb_mat_clear(U);
acb_mat_clear(T);
_perm_clear(perm);
}
flint_randclear(state);
flint_cleanup();
flint_printf("PASS\n");
return EXIT_SUCCESS;
}
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