Better logic simplification in RA - Githubissues

uwescience / raco

Compilation and rule-based optimization framework for relational algebra. Raco is the language, optimization, and query translation layer for the Myria project.

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Better logic simplification in RA #105

Open bmyerz opened 10 years ago

bmyerz commented 10 years ago

I'd at least like to cover cases where the parser produces things like $0 = $1 and $0 = $1

Perhaps we can use something like Sympy

bmyerz commented 10 years ago

Yes the following works in sympy

In [23]: And(Eq(x,y), Eq(x,y))
Out[23]: x == y

bmyerz commented 10 years ago

Not yet clear where the optimization belongs.

in toRA, when listing all conditions. Linked by conjunctions
pass over all conditions once assigned to selects, joins. Is this ever too late?

bmyerz commented 10 years ago

Depending on the backend, it might also support this optimization. Taking C++ as an example, however, there could be cases in the c-compiler where some expression simplifications are not recognized given the lower level of the code.

bmyerz commented 10 years ago

https://github.com/uwescience/datalogcompiler/tree/bmyerz-logic-simpl

bmyerz commented 10 years ago

[x] produce a sympy expression from BooleanExpression and symplify it.
[ ] find a good way to traverse the symplified expression to produce a raco BooleanExpression