Simulator: hand in rules one at a time or all together?

[sbenthall]

@llorracc writes:

An important question to think about as we move in that direction is whether the right approach is to have a simulator that just simulates one period at a time and we expect the user to feed it a sequence of rules one by one, in which case it is up to the user to feed the simulator the rules in the right order, or whether we want to be able to feed the simulator an entire sequence of decision rules and have it do all of them together and then return a result. If there were no considerations of efficiency, I'd vote for the former approach, but it could be that such an approach would be highly inefficient and slow because there would be so many objects being passed back and forth between the one-step simulator and the code that was using it to produce a sequence of periods.

[sbenthall]

I'm a little lost on this one.
@llorracc could you explain what you meant here? Otherwise, I'll close the ticket.

[llorracc]

Like, in the portfolio model.

Step	Rule	Description	State-In	State-Out
a	aFunc	consumption function yields a	m is a real; a is NaN ; PortShare is NaN	m is the same real; a is a real ; PortShare is NaN
PortShare	PortShareFunc	calculate portfolio share given a	m is same real as before; a is real caculated in a step; PortShare is NaN	m, a same reals as before; PortShare is a real between 0 and 1

All I'm saying is does our simulator:

1. Feed the input states to rule a and retrieve the output states, then take those and feed them as input states to rule PortShare, then take those, increment the period by one, and feed them to the input rule to a, or
2. Feed the input states to something that is a PortfolioModel object, which executes all the stages, then returns to the simulator all of the results of all the stages.

[sbenthall]

I think (2) can be (1) considered at a different level of abstraction.

[mnwhite]

Closing as stale, and never really understood as an issue. I agree with Seb that this is just a matter of abstraction. Efficiency-wise, passing objects in Python isn't costly because it's a memory pointer. Doing so in Matlab (e.g.) is very costly because a new copy is created in memory.