GerryChain.jl
Parker Rule, Matthew Sun, Bhushan Suwal
MGGG
motivation
SHAPEFILE_PATH = "./PA_VTD.json"
POPULATION_COL = "TOT_POP"
ASSIGNMENT_COL = "538GOP_PL"
# Initialize graph and partition
graph = BaseGraph(SHAPEFILE_PATH, POPULATION_COL, ASSIGNMENT_COL)
partition = Partition(graph, ASSIGNMENT_COL)
# Define parameters of chain (number of steps and population constraint)
pop_constraint = PopulationConstraint(graph, POPULATION_COL, 0.02)
num_steps = 10
# Initialize Election of interest
election = Election("SEN10", ["SEN10D", "SEN10R"], graph.num_dists)
# Define election-related metrics and scores
election_metrics = [
vote_count("count_d", election, "SEN10D"),
efficiency_gap("efficiency_gap", election, "SEN10D"),
seats_won("seats_won", election, "SEN10D"),
mean_median("mean_median", election, "SEN10D")
]
scores = [
DistrictAggregate("presd", "PRES12D"),
ElectionTracker(election, election_metrics)
]
# Run the chain
println("Running 10-step ReCom chain...")
chain_data = recom_chain(graph, partition, pop_constraint, num_steps, scores)
# Get values of all scores at the 10th state of the chain
score_dict = get_scores_at_step(chain_data, 10)
# Get all vote counts for each state of the chain
vote_counts_arr = get_score_values(chain_data, "count_d")
running a chain in 34 lines of code!
The speed of GerryChain depends a lot on how it is configured
Population Constraint: Tighter the bounds ➡ Longer times
Acceptance Probability: Lower probability ➡ Longer times
Number of scores: More calculation ➡ Longer times
Num steps: More steps ➡ Longer times
Comparing chains in Julia vs Python
So currently we have a ~47x speedup in Julia over Python (over simple runs)
thank you!
check us out on github? 🥺👉👈
JuliaCon 2021 Presentation
By Matthew Sun
JuliaCon 2021 Presentation
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