Hi Isaiah, thanks for your reply! Yeah, I figured my use case is probably a little exotic. I have thought very hard about using macros, but either I haven't quite understood them yet (likely!) or they aren't the best solution in this instance. Maybe some sort of symbolic approach could work where I only store Expression objects for each circuit element that get concatenated and compiled when a whole circuit is simulated.
Anyway, thanks! Nik On Wednesday, October 15, 2014 11:11:42 AM UTC-7, Isaiah wrote: > > Given the constructed sys1_ode method is there someway to dynamically >> access the captured variables, i.e. those that come from its closure? > > > I'm not sure I entirely follow, but: you can use the variables p1 and p2 > inside the inner function and it will Just Work (scoping rules). But it is > not possible to interrogate the closure environment from inside the > enclosed function. > > Also, have you considered macros? They won't help to interrogate the > closure environment, but are a much better option for AST rewriting than > using code_lowered. > > On Tue, Oct 14, 2014 at 2:14 PM, Nikolas Tezak <[email protected] > <javascript:>> wrote: > >> Hi all, >> >> in my research I run numerical simulations (ODEs and SDEs) for circuit >> models that can be composed, i.e., >> each system has an ode that modifies in-place the elements of an output >> array based on the current state variable. >> Moreover, dimensionality of each system may vary. >> >> function sys1_ode(t, x, xdot) >> xdot[1] = # some function of x, t >> xdot[2] = # some other function of x, t >> end >> >> >> function sys2_ode(t, x, xdot) >> xdot[1] = # some expression with x, t >> xdot[2] = # some other expression with x, t >> xdot[3] = # some other expression with x, t >> end >> >> >> What I would like to do is use metaprogramming to construct a combined >> ode for both systems where the state vectors are just stacked. For each >> system I compute the offset within the state vector (0 for sys1 and 2 for >> sys2) and then modify and recombine the function code as follows >> >> function sys12_ode(t, x, xdot) >> xdot[1+0] = # some expression with x[1:2], t >> xdot[2+0] = # some other expression with x[1:2], t >> xdot[1+2] = # some expression with x[1+2:3+2], t >> >> xdot[2+2] = # some expression with x[1+2:3+2], t >> xdot[3+2] = # some expression with x[1+2:3+2], t >> >> end >> >> >> So far, that would seem to be quite straightforward and I think I could >> get this working by calling code_lowered(sys1_ode) and using the rewritten >> output to construct an AST for the combined function. >> >> The difficulty now arises when my sys1 and sys2 odes are defined with >> some internal parameters that are not passed as an argument but rather >> through a closure from the surrounding scope, i.e. I have some ode factory: >> >> funcion make_sys1_ode(p1, p2) >> function sys1_ode(t, x, xdot) >> xdot[1] = # some expression with x, t AND p1, p2 >> xdot[2] = # some expression with of x, t AND p1, p2 >> end >> sys1_ode >> end >> >> Given the constructed sys1_ode method is there someway to dynamically >> access the captured variables, i.e. those that come from its closure? >> Otherwise, I suppose I could resort to passing parameters via an extra >> ODE argument, but it would be super nice if I could avoid this. >> The reason why I am trying to implement things this way is to speed up >> ODE evaluation for very large complex (i.e. nested) circuits by expanding >> out all ODE bodies into a single function. >> >> I hope this write-up makes sense. >> Thanks, >> Nik >> >> >
