Imperative events in the DSL

[kaandocal]

Hey, first of all - massive congratulations on all this work over the past few years! The amount of supported functionality added over the past year or two is crazy, and I'm really enjoying the current version! As I may have gone a bit overboard with my modelling I ran into a small problem recently (bug/feature request?). Namely, I want to use the experimental MTK.ImperativeAffect interface within the DSL, which does not seem to be supported:

function affect(x, obs, ctx, int)
    dX = rand(Poisson(1))
    @set! x.X = x.X + dX
end 

rn = @reaction_network begin
    k, 0 --> X

    @discrete_events begin 
        1.0 => affect
    end 
end

This throws the following error:

The affect part of all events (the right-hand side) must be a vector. This is not the case for: affect.

in Catalyst.read_events_option. This is because the DSL expects affects of the form [ X ~ X + 1 ], even though MTK supports more general affect functions.

My current solution is:

• hack the code for Catalyst.read_events_option to remove those checks
• create affect_wrapper = MTK.ImperativeAffect(...) wrapping the affect function
• use the line 1.0 => $affect_wrapper

This seems to work, but is messy. Any chance one could incorporate this into the DSL by fine-tuning these checks?

Alternatively, is there a convenient way of adding events to an existing reaction system (copies are fine)? It seems like I'd have to manually recreate one to do so, which involves copying a lot of fields and is very reliant on Catalyst internals...

As an extension, I'd like to have random times between these events. I might be able to concoct something using JumpProcesses, but is there an easier way to do this with newer versions?

[kaandocal]

Update: You can create a network component and then use

rn = extend(rn, [ ReactionSystem(t; name=:events, continuous_events=[1.0 => affect_wrapper]) ])

I had to use ParentScope to deal with variable name issues, which is not very elegent, but this works for now (I think)!

[TorkelE]

Happy you managed to find a solution. We are hoping to do the next major release soon, which will come with some chanegs to events. Hopefully we will be able to integrate proper DSL support for this then.