Test for dimensionless object

[nopria]

How can I determine if a sympy object is dimensionless, i.e. is a pure number and not a physical quantity? This is related to issue #14374, the problem arises when the input is zero, or more exactly sympy.core.numbers.Zero, which might mean both a zero pure number and 0 cm, 0 kg, 0 newton, etc.. I'm looking for workarounds until the issue is solved.

[oscarbenjamin]

Ideally obj.kind would give you this.

[nopria]

How sympy.core.numbers.Zero.kind can dintinguish if zero comes from 0*45 or from 0*(45*meters) ?

[oscarbenjamin]

The check should be used before evaluation.

[nopria]

The problem is that it can't. In real coding you have to deal with processes which involve hundreds of multiplications at the end of which you have to check if the value is dimensionless or not in order to proceed with more hundreds of multiplications and so on.

[oscarbenjamin]

I mean that the internal code of Mul should check .kind