How to convert the co-efficients in these inequalities from float to int in Sympy?-CodePudding

I have the following expressions -

x > 4.5
2x   y == 4.5

I would like to get rid of the floating point numbers in the coefficients and convert them into integers. How can I do this using Sympy? (or any other python library for that matter). I have been racking my brains for hours now.

BTW, the expected output should be -

2x > 9
4x   2y == 9

Thanks in Advance!

CodePudding user response：

You can use nsimplify() on the relation and multiply both sides by the denominator of the RHS, like the following.

from sympy import nsimplify, Rel
from sympy.abc import x

r0 = x > 4.5

r = nsimplify(r0)
q = r.rhs.q
r = Rel(r.lhs * q, r.rhs * q, r.rel_op)

print([r0, r])

This outputs

[x > 4.5, 2*x > 9]

CodePudding user response：

If you want to clear all denominators (even those that may be symbolic) then this might be a robust way to do so:

def clear_relden(r):
    from sympy.core.relational import Relational
    from sympy import Piecewise
    assert isinstance(r, Relational)
    n, d = zip(*[i.as_numer_denom() for i in r.args])
    l = lcm(*d)
    args = [n[i]*l/d[i] for i in range(2)]
    return Piecewise(
        (r.func(*args), l>0),
        (r.reversed.func(*args), l<0))

For example,

If you have floats, then pass nsimplify(r, rational=True).