Hello,
What would you think of adding mpq_mul_ui, mpq_div_ui, mpq_ui_div, and
also the _z versions?
Something like (untested)
void
mpq_mul_ui (mpq_ptr prod, mpq_srcptr op, unsigned long m)
{
unsigned long gcd_ui;
if (SIZ (NUM (op)) == 0 || m == 0)
{
/* We special case this to simplify allocation logic; gcd(0,x) = x
is a singular case for the allocations. */
SIZ (NUM (prod)) = 0;
MPZ_NEWALLOC (DEN (prod), 1)[0] = 1;
SIZ (DEN (prod)) = 1;
return;
}
#if 0
if (m == 1)
{
if (prod != op)
mpq_set (prod, op);
return;
}
#endif
gcd_ui = mpz_gcd_ui (0, DEN (op), m);
#if 0
if (gcd_ui == 1)
{
mpz_mul_ui (NUM (prod), NUM (op), m);
if (prod != op)
mpz_set (DEN (prod), DEN (op));
}
#endif
mpz_mul_ui (NUM (prod), NUM (op), m / gcd_ui);
mpz_divexact_ui (DEN (prod), DEN (op), gcd_ui);
// mpz_divexact_gcd (DEN (prod), DEN (op), gcd_z);
}
mpq_add_ui is easy to emulate with mpz_addmul_ui, but mpq_mul_ui is a bit
harder (3 operations plus the need to handle 0 explicitly).
I can add similar code directly in gmpxx.h, but I first wanted to check if
a C version was desirable.
--
Marc Glisse
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