Files
drift/training/walk_forward.py
T
Mark Aron Szulyovszky cc7061b456 feat(Core): ensemble models, correct forward returns calculation, scaling, only train from when asset returns are available, major bug fixed in walk_forward_train_test (#35)
* fix(Core): correct forward returns calculation, classifiers are now working again, only train from when asset returns are available

* feat(Utils): added get_first_valid_return_index()

* feat(Ensemble): return models from `run_whole_pipeline`

* feat(Ensemble): added ensemble step, fixed walk_forward_train_test predictions index confusion,

* chore(Pipeline): remove unnecessary extra ensemble results dataframe

* refactor(Core): removed unnecessary ensemble_train_predict, moved run_single_asset_trainig_pipeline to a separate file

* feat(Training): added scaling on expanding window (the past) to walk_forward_train_test(), now printing out mean sharpe ratio

* feat(CI): added environment.yml file

* chore(Environment): update env.yml

* feat(CI): added testing workflow

* fix(CI): renamed enviroment.yml

* fix(Tests): added missing new parameter to walk_forward_train_test()
2021-12-17 14:32:17 +01:00

64 lines
2.3 KiB
Python

import pandas as pd
from sklearn.base import clone
from utils.typing import SKLearnModel
import numpy as np
from utils.helpers import get_first_valid_return_index
def walk_forward_train_test(
model_name: str,
model: SKLearnModel,
X: pd.DataFrame,
y: pd.Series,
target_returns: pd.Series,
window_size: int,
retrain_every: int,
scaler,
) -> tuple[pd.Series, pd.Series]:
assert len(X) == len(y)
predictions = pd.Series(index=y.index).rename(model_name)
models = pd.Series(index=y.index).rename(model_name)
first_nonzero_return = max(get_first_valid_return_index(target_returns), get_first_valid_return_index(X.iloc[:,0]))
train_from = first_nonzero_return + window_size + 1
train_till = len(y)
iterations_since_retrain = 0
if scaler is not None:
scaler = clone(scaler)
for index in range(train_from, train_till):
iterations_since_retrain += 1
if iterations_since_retrain >= retrain_every or pd.isna(models[index-1]):
train_window_start = index - window_size - 1
train_window_end = index - 1
if scaler is not None:
# First we need to fit on the expanding window data slice
# This is our only way to avoid lookahead bia
X_expanding_window = X[first_nonzero_return:train_window_end]
scaler.fit(X_expanding_window)
X_slice = X[train_window_start:train_window_end]
y_slice = y[train_window_start:train_window_end]
if scaler is not None:
X_slice = scaler.transform(X_slice)
else:
X_slice = X_slice.to_numpy()
current_model = clone(model)
current_model.fit(X_slice, y_slice.to_numpy())
iterations_since_retrain = 0
else:
current_model = models[index-1]
models[index] = current_model
next_timestep = X.iloc[index].to_numpy().reshape(1, -1)
prediction = current_model.predict(next_timestep).item()
predictions[index] = prediction
return models, predictions