GSoC 2019: Week 10 and 11

So, the second last week of the official coding period is over now. During the last two weeks, I was mostly occupied with on-campus placement drives, hence I couldn’t put up a blog earlier. A summary of my work during these weeks is as follows:

• First of all, #17144 is merged 😄. This was a large PR and hence took time to get fully reviewed. With this, the performance of New assumptions comes closer to that of the old system. Currently, queries are evaluated about 20X faster than before.

• #17379 attempts to remove SymPy’s costly rcall() from the whole assumptions mechanism. It’s a follow-up from #17144 and the performance gain is subtle for large queries. E.g.

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  from sympy import * p = random_poly(x, 50, -50, 50) print(ask(Q.positive(p), Q.positive(x)))

  In the master it takes 4.292 s, out of this 2.483 s is spent in rcall. With this, the time spent is 1.929 s and 0.539 s respectively.

• #17392 attempts to make the New Assumptions able to handle queries which involve Relationals. Currently, it works only with simple queries (e.g. ask(x>y, Q.positive(x) & Q.negative(y)) now evaluates True) just like the way old system works. This is a much-awaited functionality for the new system. Also, during this I realized that sathandlers lack many necessary facts. This PR also adds many new facts to the system.

For the last week of coding, my attempt would be to complete both of these PRs and get them merged. Also, I will try to add new facts to sathandlers.