long_extras.h – support functions for signed word arithmetic

Properties

size_t z_sizeinbase(slong n, int b)

Returns the number of digits in the base $b$ representation of the absolute value of the integer $n$.

Assumes that $b\ge 2$.

Checked Arithmetic

int z_mul_checked(slong *a, slong b, slong c)

Set $\ast a$ to $b$ times $c$ and return $1$ if the product overflowed. Otherwise, return $0$.

Random functions

slong z_randtest(flint_rand_t state)

Returns a pseudo random number with a random number of bits, from $0$ to FLINT_BITS. The probability of the special values $0$, $\pm 1$, COEFF_MAX, COEFF_MIN, WORD_MAX and WORD_MIN is increased.

This random function is mainly used for testing purposes.

slong z_randtest_not_zero(flint_rand_t state)

As for z_randtest(state), but does not return $0$.

slong z_randint(flint_rand_t state, ulong limit)

Returns a pseudo random number of absolute value less than limit. If limit is zero or exceeds WORD_MAX, it is interpreted as WORD_MAX.

Modular arithmetic

int z_kronecker(slong a, slong n)

Return the Kronecker symbol $\left(\frac{a}{n}\right)$ for any $a$ and any $n$.