void
mpz_rootrem (mpz_ptr root, mpz_ptr rem, mpz_srcptr u, unsigned long int nth)
{
mp_ptr rootp, up, remp;
mp_size_t us, un, rootn, remn;
up = PTR(u);
us = SIZ(u);
/* even roots of negatives provoke an exception */
if (us < 0 && (nth & 1) == 0)
SQRT_OF_NEGATIVE;
/* root extraction interpreted as c^(1/nth) means a zeroth root should
provoke a divide by zero, do this even if c==0 */
if (nth == 0)
DIVIDE_BY_ZERO;
if (us == 0)
{
if (root != NULL)
SIZ(root) = 0;
SIZ(rem) = 0;
return;
}
un = ABS (us);
rootn = (un - 1) / nth + 1;
if (root != NULL)
{
rootp = MPZ_REALLOC (root, rootn);
up = PTR(u);
}
else
{
rootp = __GMP_ALLOCATE_FUNC_LIMBS (rootn);
}
MPZ_REALLOC (rem, un);
remp = PTR(rem);
if (nth == 1)
{
MPN_COPY (rootp, up, un);
remn = 0;
}
else
{
remn = mpn_rootrem (rootp, remp, up, un, nth);
}
if (root != NULL)
SIZ(root) = us >= 0 ? rootn : -rootn;
else
__GMP_FREE_FUNC_LIMBS (rootp, rootn);
SIZ(rem) = remn;
}
int
mpz_root (mpz_ptr root, mpz_srcptr u, mpir_ui nth)
{
mp_ptr rootp, up;
mp_size_t us, un, rootn, remn;
TMP_DECL;
us = SIZ(u);
/* even roots of negatives provoke an exception */
if (us < 0 && (nth & 1) == 0)
SQRT_OF_NEGATIVE;
/* root extraction interpreted as c^(1/nth) means a zeroth root should
provoke a divide by zero, do this even if c==0 */
if (nth == 0)
DIVIDE_BY_ZERO;
if (us == 0)
{
if (root != NULL)
SIZ(root) = 0;
return 1; /* exact result */
}
un = ABS (us);
rootn = (un - 1) / nth + 1;
TMP_MARK;
/* FIXME: Perhaps disallow root == NULL */
if (root != NULL && u != root)
rootp = MPZ_REALLOC (root, rootn);
else
rootp = TMP_ALLOC_LIMBS (rootn);
up = PTR(u);
if (nth == 1)
{
MPN_COPY (rootp, up, un);
remn = 0;
}
else
{
remn = mpn_rootrem (rootp, NULL, up, un, (mp_limb_t) nth);
}
if (root != NULL)
{
SIZ(root) = us >= 0 ? rootn : -rootn;
if (u == root)
MPN_COPY (up, rootp, rootn);
}
TMP_FREE;
return remn == 0;
}