Geo-Simulations. Saulo Henrique Cabral Silva. Tiago Garcia de Senna Carneiro*. TerraLAB. – . Laboratory. for . Earh. System . Modeling. . and. . Simulation. Computer. . Science. . Department. ID: 372673
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High Performance Geo-Simulations
Saulo Henrique Cabral Silva
Tiago Garcia de Senna Carneiro*
Modelers have few programming expertise
Problem partition into several processes?
What is the design goal: Scalability or Performance?
Local scheduling high performance
How to parallelize/distribute workload?
Model architecture can be defined by:
Application domain area (the phenomenon being modeled)
Chosen modeling paradigm: CA,
, DEVS, etc
Which load balancing strategy to use?
How to verify models with no influence of concurrency control rules?Slide3
predatores[i]:execute() end function execAgentPrey(i) preys[i]:execute() end for i = 1, #predatores do --HPA PARALLEL execAgentPred(i) end --HPA JOINALL for i = 1, #preys do --HPA PARALLEL execAgentPrey(i) end --HPA JOINALL
Annotations - API:
HPA PARALLEL HPA JOIN function_name HPA JOINALL HPA ACQUIRE resource_name HPA RELEASE resource_name
Flexibility through annotation: Prey-predator modelSlide4
Scalability through load balance: Bag of TasksSlide5
when the modeler designs efficient parallel solutions
90% of linear speedup
with 8 processors (prey predator model)
35% of linear speedup
with 8 processors (TROLL model)Slide6
EXP1: Spatially-explicit prey predator model
Species compete, evolve and disperse, in order to seek resources to support their struggle for their existence
Each cell has a population of prey and a population of predators
Model executes in two steps:
First, predators are simulated in parallel
Then, prey are simulated in parallelSlide7Slide8Slide9
Distributed (Dmason) versus Parallel (TerraME)Slide10
Agents Clusters versus Load BalancingSlide11
EXP2: 3D tropical rain forest growth model - TROLL
TROLL model simulates a 3D environment where:
Individual trees compete for light
Seed dispersal by wind
Trees interacts falling over others and forming gaps…Adopted partitioning strategy: each layer (h, h-1, h-2, …) is simulated in parallelHigher layers are simulated before lower layersSlide12Slide13Slide14