Files
drift/utils/walk_forward.py
T
Mark Aron Szulyovszky 6440ced32c feat(Tests): added basic unit tests for walk_forward_train_test() (#22)
* feat(Tests): added basic unit tests for walk_forward_train_test()

* fix(Tests): inherit from BaseEstimator, fix index problems in walk_forward_train_test

* fix(WalkForward): predictions were mistakenly removed, oops

* fix(WalkForward): mistakenly re-assiging model
2021-12-15 17:54:03 +01:00

44 lines
1.4 KiB
Python

import pandas as pd
from sklearn.base import clone
from utils.typing import SKLearnModel
import numpy as np
def walk_forward_train_test(
model_name: str,
model: SKLearnModel,
X: pd.DataFrame,
y: pd.Series,
window_size: int,
retrain_every: int
) -> tuple[pd.Series, pd.Series]:
predictions = pd.Series(index=y.index).rename(model_name)
models = pd.Series(index=y.index).rename(model_name)
train_from = window_size
train_till = y.index[-1]
iterations_since_retrain = 0
for i in range(train_from, train_till):
iterations_since_retrain += 1
window_start = i - window_size
window_end = i
X_slice = X[window_start:window_end]
y_slice = y[window_start:window_end]
if iterations_since_retrain >= retrain_every or pd.isna(models[i-1]):
current_model = clone(model)
current_model.fit(X_slice.to_numpy(), y_slice.to_numpy())
iterations_since_retrain = 0
else:
current_model = models[i-1]
models[window_end] = current_model
next_timestep = X.iloc[window_end+1].to_numpy().reshape(1, -1)
predictions[window_end+1] = current_model.predict(next_timestep).item()
return models, predictions