These are chat archives for symengine/symengine

Dec 2015
Ondřej Čertík
Dec 16 2015 17:17
@isuruf, @rwst As we discussed in the issues, I think the way to go is to have a dedicated class Series, that handles the series including printing the O() term. This Series will subclass from Basic. As to Series + Add let's say, the result should be handled and result in a Series I guess. The other option is to not make Series subclass Basic. I don't know.
Isuru Fernando
Dec 16 2015 17:20
@certik, one disadvantage of Series and Polynomial subclassing Basic is that then x which is a Symbol and x which is a polynomial will not be equal. Making them equal will be lots of hard work as we have no way yet for equality of different types
Ondřej Čertík
Dec 16 2015 20:11
I don't think they should be equal, should they?
Ralf Stephan
Dec 16 2015 20:49
Series and polynomials may not be general Expressions but they could be converted to them, and then they can be compared. You need to distinguish between algebraic equality (x==(x+1)**2-x**2-x-1) and equality of objects (x is y).
Ondřej Čertík
Dec 16 2015 21:05
They should be subclassed if you want to represent things like (x+y+z+1)^2, where x+y+z+1 is a polynomial, but then you square it using Pow. Otherwise they don't have to be and just need methods to convert to and from Basic.