Installation

pip install boltzmannclean

Usage

To fill in missing values from a DataFrame with the minimum of fuss, a cleaning function is provided.

import boltzmannclean

my_clean_dataframe = boltzmannclean.clean(
    dataframe=my_dataframe,
    numerical_columns=['Height', 'Weight'],
    categorical_columns=['Colour', 'Shape'],
    tune_rbm=True  # tune RBM hyperparameters for my data
)

To create and use the underlying scikit-learn transformer.

my_rbm = boltzmannclean.RestrictedBoltzmannMachine(
    n_hidden=100, learn_rate=0.01,
    batchsize=10, dropout_fraction=0.5, max_epochs=1,
    adagrad=True
)

my_rbm.fit_transform(a_numpy_array)

Here the default RBM hyperparameters are those listed above, and the numpy array operated on is expected to be composed entirely of numbers in the range [0,1] or np.nan/None. The hyperparameters are:

• n_hidden: the size of the hidden layer

• learn_rate: learning rate for stochastic gradient descent

• batchsize: batchsize for stochastic gradient descent

• dropout_fraction: fraction of hidden nodes to be dropped out on each backward pass during training

• max_epochs: maximum number of passes over the training data

• adagrad: whether to use the Adagrad update rules for stochastic gradient descent

Example

import boltzmannclean
import numpy as np
import pandas as pd
from sklearn import datasets

iris = datasets.load_iris()

df_iris = pd.DataFrame(iris.data,columns=iris.feature_names)
df_iris['target'] = pd.Series(iris.target, dtype=str)

df_iris.head()

Add some noise:

noise = [(0,1),(2,0),(0,4)]

for noisy in noise:
    df_iris.iloc[noisy] = None

df_iris.head()

Clean the DataFrame:

df_iris_cleaned = boltzmannclean.clean(
    dataframe=df_iris,
    numerical_columns=[
        'sepal length (cm)', 'sepal width (cm)',
        'petal length (cm)', 'petal width (cm)'
    ],
    categorical_columns=['target'],
    tune_rbm=True
)

df_iris_cleaned.round(1).head()

The larger and more correlated the dataset is, the better the imputed values will be.