Is there an implementation of _rational_ interval arithmetic in Python?

Question

Is there an implementation of rational interval arithmetic in Python? This uses floats, not rational ones.

If not, is there any rationalization implementation in Python that includes ± ∞?

Answer 1

Sympy has intervals , rational numbers, and infinity. The Interval class is a subclass of the Set class.

# oo is the symbol for infinity from sympy import Interval, oo, Rational i1 = Interval(10, 15) i2 = Interval(0, oo) i3 = Interval(-5, -1) # adding intervals i4 = i1 + i3 i5 = i1 + i2 # interval with open end i6 = Interval(Rational(1, 2), Rational(45, 3), left_open=True) print 11 in i1 # True print -1 in i1 # False print 0 in i4 # False print Rational(3, 2) in i6 # True print oo in i2 # False print i2.sup # oo (infinity) print Rational(1, 2) in i6 # False print i6.inf # 1/2 

Answer 2

PyInterval now has rational interval arithmetic in Python functions.

From PyInterval Docs :

An interval package can be loaded into the Python interpreter using an operator that introduces an interval class, a constant representing mathematical infinity, and a module that provides interval transcendental functions to the current namespace.

 from interval import interval, inf, imath interval[0, 2] * interval[4, inf] interval([-inf, inf])