[Discussion] Implementing apart for symengine

[jmig5776]

I was looking up the code and algorithm for apart function in SymPy to be implemented in Symengine. I have some doubts to discuss because I am a beginner in development in c++, I read about RCP to get a better understanding. These are the points to discuss:

• What should be the input and output APIs for this apart function
  In Sympy it had these kind of APIs

def apart(f, x=None, full=False, **options):
    Compute partial fraction decomposition of a rational function.

what f should be defined in symengine (uratpoly or uintpoly or Mexprpoly) it is confusing as things are not clear due to lack of documentation.

• What it should named and the class name and rest other things.
• And somewhere in apart function of SymPy there is a check for multivariate like this

if P.is_multivariate:
        fc = f.cancel()
        if fc != f:
            return apart(fc, x=x, full=full, **_options)

        raise NotImplementedError(
            "multivariate partial fraction decomposition")

As far as I know, currently symengine has only focussed with univariate. Am I right?

• Please let me know what other things i should keep in mind if you have a suggestion for me.

References
#1324

CC @certik @isuruf

[certik]

Thanks for starting to look at things. The input at the highest level should be const RCP<const Basic> &f. Then it should convert it to polynomials (if needed) internally, do the "apart" algorithm, and then return the object back as RCP<const Basic>.

@isuruf which polynomial class should this use for univariate polynomials?

@jmig5776 I would suggest you get some prototype that only works for a small subset of expressions, and then we'll iteratively improve it. Thank you again for working on this, this will be a very useful addition to SymEngine.

[jmig5776]

Sure @certik My exams just got over today I will soon be sending PR regarding that. I am sorry for the delay.