Implementation of Schelling's segregation model example #853
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| return FLAMEGPU->getVariable<unsigned int>("available"); | ||
| } | ||
| FLAMEGPU_AGENT_FUNCTION(output_available_locations, flamegpu::MessageNone, flamegpu::MessageArray) { | ||
| FLAMEGPU->message_out.setIndex(FLAMEGPU->getThreadIndex()); |
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Why is getThreadIndex() still required? I doubt Paul will like this being used.
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I guess it's because you only have a random selection of locations available, which aren't a contiguous block. So you need a way agents can identify valid spots, and this is a fairly simple method.
Not sure of a better approach off the top of my head, maybe one for discussion in the meeting.
Iirc, Primage's bonding was more all-to-all so didn't suffer from this.
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Having thought about this, I guess the 'proper' way would be for the spaces_available property to be binned, and a spaces_available brute force message list created.
Spaces available output a message which only contains their ID, Agents then grab the list, check it's length and generate a random number to grab the message at that index. (Brute force messages don't currently have direct access like an array, so would need iterating, but there's no practical reason it couldn't be added).
One benefit of this 'proper' version is that it would better facilitate agents with more specific preferences, as the spaces_available message could be improved to list any number of features of the space which the agent must approve of. (Although we might want to think about a more generalised version of Spatial messaging for multi-dimensional data if this were to be a real thing).
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| FLAMEGPU_AGENT_FUNCTION(select_winners, flamegpu::MessageBucket, flamegpu::MessageArray) { | ||
| // First agent in the bucket wins |
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More expensive, but technically more 'fair' to have agents roll a random float which they attach to the message, and the highest/lowest float wins.
| return flamegpu::ALIVE; | ||
| } | ||
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| FLAMEGPU_AGENT_FUNCTION_CONDITION(is_available) { |
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Might benefit from a comment above this, to denote the remaining functions are from the iterative submodel.
(My initial thought was to split the entire submodel into a seperate header or source file, like I've done in primage to aid readability, but probably overkill for the small model (and I doubt I did it for sugar scape).
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| // Configurable properties | ||
| constexpr unsigned int GRID_WIDTH = 100; | ||
| constexpr float THRESHOLD = 0.70; |
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0.70f (This is the Windows CI fail)
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| // Functions | ||
| auto& outputLocationsFunction = agent.newFunction("output_available_locations", output_available_locations); | ||
| outputLocationsFunction.setMessageOutput("available_location_message"); |
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My gut feeling is that branching inside agent functions would be cheaper than an agent function condition (which involves a sort of the agents after launching an agent function to create the filter value).
I think agent function conditions exist as a way to partition agents in stateful models.
But we probably don't have any models which demonstrate that, so eh.
Again, one for discussion at meeting.
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It'll depend on how complex the function with the branching is, how big the populations are, if there's room for concurrency by splitting the pop, and how grouped together the agents which follow each branch would be (plus other things). It's something that we should probably investigate at some point to make recommendations about when to use it (if it follows a sane pattern wrt the abov epoints)
MILeach
changed the title
fixes windows warning
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A revised / FLAME GPU 2.0.0-rc compatible version of this is in FLAMEGPU/ABM_Framework_Comparisons. https://github.com/FLAMEGPU/ABM_Framework_Comparisons/blob/FLAMEGPU2/FLAMEGPU2/src/schelling.cu The size will want to be reduced. |
This works but currently relies on some questionable code, specifically using cuda thread index to allow an unusual access pattern to a message list.