PClean
PClean: A Domain-Specific Probabilistic Programming Language for Bayesian Data Cleaning
Warning: This is a rapidly evolving research prototype.
PClean was created at the MIT Probabilistic Computing Project.
If you use PClean in your research, please cite the our 2021 AISTATS paper:
PClean: Bayesian Data Cleaning at Scale with Domain-Specific Probabilistic Programming. Lew, A. K.; Agrawal, M.; Sontag, D.; and Mansinghka, V. K. (2021, March). In International Conference on Artificial Intelligence and Statistics (pp. 1927-1935). PMLR. (pdf)
Using PClean
To use PClean, create a Julia file with the following structure:
using PClean
using DataFrames: DataFrame
import CSV
# Load data
data = CSV.File(filepath) |> DataFrame
# Define PClean model
PClean.@model MyModel begin
@class ClassName1 begin
...
end
...
@class ClassNameN begin
...
end
end
# Align column names of CSV with variables in the model.
# Format is ColumnName CleanVariable DirtyVariable, or, if
# there is no corruption for a certain variable, one can omit
# the DirtyVariable.
query = @query MyModel.ClassNameN [
HospitalName hosp.name observed_hosp_name
Condition metric.condition.desc observed_condition
...
]
# Configure observed dataset
observations = [ObservedDataset(query, data)]
# Configuration
config = PClean.InferenceConfig(1, 2; use_mh_instead_of_pg=true)
# SMC initialization
state = initialize_trace(observations, config)
# Rejuvenation sweeps
run_inference!(state, config)
# Evaluate accuracy, if ground truth is available
ground_truth = CSV.File(filepath) |> CSV.DataFrame
results = evaluate_accuracy(data, ground_truth, state, query)
# Can print results.f1, results.precision, results.accuracy, etc.
println(results)
# Even without ground truth, can save the entire latent database to CSV files:
PClean.save_results(dir, dataset_name, state, observations)
Then, from this directory, run the Julia file.
JULIA_PROJECT=. julia my_file.jl
To learn to write a PClean model, see our paper, but note the surface syntax changes described below.
Differences from the paper
As a DSL embedded into Julia, our implementation of the PClean language has some differences, in terms of surface syntax, from the stand-alone syntax presented in our paper:
(1) Instead of latent class C ... end
, we write @class C begin ... end
.
(2) Instead of subproblem begin ... end
, inference hints are given using ordinary
Julia begin ... end
blocks.
(3) Instead of parameter x ~ d(...)
, we use @learned x :: D{...}
. The set of
distributions D for parameters is somewhat restricted.
(4) Instead of x ~ d(...) preferring E
, we write x ~ d(..., E)
.
(5) Instead of observe x as y, ... from C
, write @query ModelName.C [x y; ...]
.
Clauses of the form x z y
are also allowed, and tell PClean that the model variable
C.z
represents a clean version of x
, whose observed (dirty) version is modeled
as C.y
. This is used when automatically reconstructing a clean, flat dataset.
The names of built-in distributions may also be different, e.g. AddTypos
instead of typos
,
and ProportionsParameter
instead of dirichlet
.