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// Copyright 2013 Michael E. Stillman
#include "aring-zz-flint.hpp"
#include "ringmap.hpp"
namespace M2 {
ARingZZ::ARingZZ()
{
flint_randinit(mRandomState);
fmpz_init(mMaxHeight);
fmpz_set_ui(mMaxHeight, 100);
}
// This function will likely not ever get called.
ARingZZ::~ARingZZ()
{
flint_randclear(mRandomState);
fmpz_clear(mMaxHeight);
}
void ARingZZ::eval(const RingMap* map,
const ElementType& f,
int first_var,
ring_elem& result) const
{
mpz_t temp;
flint_mpz_init_set_readonly(temp, &f);
result = map->get_ring()->from_int(temp);
flint_mpz_clear_readonly(temp);
}
void ARingZZ::elem_text_out(buffer& o,
const ElementType& a,
bool p_one,
bool p_plus,
bool p_parens) const
{
char* str;
bool is_neg = (fmpz_cmp_si(&a, 0) == -1);
bool is_one = (fmpz_cmp_si(&a, 1) == 0 || fmpz_cmp_si(&a, -1) == 0);
if (!is_neg && p_plus) o << '+';
if (is_one)
{
if (is_neg) o << '-';
if (p_one) o << '1';
}
else
{
str = fmpz_get_str(static_cast<char*>(0), 10, &a);
o << str;
}
}
void ARingZZ::syzygy(const ElementType& a,
const ElementType& b,
ElementType& x,
ElementType& y) const
{
assert(!is_zero(b));
// First check the special cases a = 0, b = 1, -1. Other cases: use gcd.
if (is_zero(a))
{
set_from_long(x, 1);
set_zero(y);
return;
}
if (fmpz_cmp_ui(&b, 1) == 0)
{
set_from_long(x, 1);
negate(y, a);
return;
}
if (fmpz_cmp_si(&b, -1) == 0)
{
set_from_long(x, 1);
set(y, a);
return;
}
ElementType g;
init(g);
fmpz_gcd(&g, &a, &b);
divide(y, a, g);
divide(x, b, g);
if (fmpz_sgn(&x) > 0)
negate(y, y);
else
negate(x, x);
clear(g);
}
};
// Local Variables:
// compile-command: "make -C $M2BUILDDIR/Macaulay2/e "
// indent-tabs-mode: nil
// End:
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