In operations_broadcast_test.go there are some tests that are not yet filled in. The point is to test that broadcasting works for different shapes. The semantics of broadcast probably isn't clear, so please do send me a message for anything.

This is a good first issue for anyone looking to get interested

Printing a Variable instance displays the complete formula defining the variable. However, this comes in form of a (possibly very long) string that may be hard to parse with the naked eye.

A pretty-printing option would instead produce a well-formatted system of equations representing a complete computation graph.

Current, the only types we have on the graph are:

• Constants
• Variables

We must add parameters which can later on be requested/getted by their IDs (just like variables)