Owl_base_mathsMaths: fundamental and advanced mathematical functions.
``is_inf x`` returns ``true`` if ``x`` is ``infinity`` or ``neg_infinity``.
``is_pow2 x`` return ``true`` if ``x`` is integer power of 2, e.g. 32, 64, etc.
``same_sign x y`` returns ``true`` if ``x`` and ``y`` have the same sign, otherwise it returns ``false``. Positive and negative zeros are special cases and always returns ``true``.
``is_simplex x`` checks whether ``x`` is simplex. In other words, :math:`\sum_i^K x_i = 1` and :math:`x_i \ge 0, \forall x_i \in 1,K`.
``is_prime x`` returns ``true`` if ``x`` is a prime number. The function is deterministic for all numbers representable by an int. The function uses the Rabin–Miller primality test.