Should is_square be in the main namespace?

[asmeurer]

We have is_square in sympy.ntheory.primetest, but it isn't included in the main __init__.py.

It seems to do a lot more than the naive test that most people would use, and also more than perfect_power(x, [2]), which it falls back on.

Should we add it to the main namespace?

[smichr]

I recall working with those functions a fair amount. That function is optimal for determining, as docstring says, whether something is not square -- i.e. it should be used as a confirmation that something is not square. So if is_square(n) reads "I doubt that n is square, but it it is...". To use perfect_power requires two steps: q = perfect_power(n, [2]); if q and not q[1]%2.

[sylee957]

is_square is also used in matrix predicates for completely different purpose, but it can be managable if matrix module doesn't make those predicates loose.

[asmeurer]

We could rename it to is_square_number, although there are a lot of functions that use scalar names that apply differently when used in a matrix context.

[asmeurer]

That function is optimal for determining, as docstring says, whether something is not square -- i.e. it should be used as a confirmation that something is not square.

What would be an example of misuse? Most numbers aren't squares, so I would expect generic use of the function to have this condition.