December 1st, 2011, 2:32 pm
(moved here from the MC thread)QuoteTo take an example in the case of 1 factor, the 3 levels are:1. SDE part (manufacturing model)2. FDM/numerics part (tracking model)3. High-level MIS info (e.g. statistics, post-processing convergence results, VAR)This process can be generalised.Design each subsystem until we get to patterns and code. This approach is used by many software designers. AFAIK this approach is needed if you want a parallel solution as bottom-up OO approach is not so easy to parallelise. ...Thus, I would avoid GOF Observer and deploy design 'parallel' from day 1. Use signals-based Propagator pattern is more flexible....The main effort is the assembly of all the bespoke 'interoperable' building blocks (which you already completed?) into the main design.Thanks Cuch!(sorry but what is MIS again?) Anyway the setting seems now clearer, and I agree especially on the parallel issue, at least in theory. In practice one problem often encountered is that part of the design constraints&inconsistencies become visible only while crafting actual code, kind of chicken&egg problem. Futile exercise until an alternative is offered, I reckon, and top-down has important advantages. So, if I got the setting correctly, it's clear that the "steps/levels" need not be fixed and can be a lot more (see e.g. the 10 step Prayer from Meucci, and there's not yet credit in there), not only in the sense of further refinement, right?And there shall be no hierarchy/directional dependency imposed a-priori; e.g. at a finer granularity one might want to get both ways:- invCDF <- CDF <- PDF <- characteristic- PDF -> characteristic -> whatever...And the levels/components can also mix/feedback sometimes (e.g. optimizing netted positions iirc).This might look like absence of structure and loss of a top-down view, but isn't really, it's mainly about loose coupling and "cross sectional" concepts reused at different stages (metaconcepts? can anyone but me understand this sentence?)... Too challenging?I feel that propagator here can be really useful! Or is this flexibility something else and playing against what you meant? But (in my ignorance) I am worried of propagator's overhead and complexity, so it would be great to get clearly defined when it's really needed versus where can lighter alternatives be enough.
Last edited by
quartz on November 30th, 2011, 11:00 pm, edited 1 time in total.