Arithmetic on Literals

[dwf]

Arithmetic on Literals should work.

• Should it happen immediately for Literal-Literal operations?
• Should the __add__, etc. methods be in Node?

[jaberg]

Based on my sympy vs. Theano experience, I would suggest that operators acting on literals return non-literals. A separate function can do a depth-first collapsing of the literals in a graph, and be called automatically by other functions that act on whole-graphs. Strongest considerations: information preservation about call graph, programmer-friendliness.

Re: __add__ in Node... a lot of operators will produce results for which addition is undefined, will that be a problem?