Prepare the series
Assemble a chronological dataset with stable timestamps, handle missing values and create a walk-forward validation split so future data is never used for training.
Apply a wavelet transform. Inspect the transformed components.
Wavelet transforms decompose a time series into components at multiple scales and are useful for isolating trends, seasonal components and transient events. Common error cases include boundary effects, poor choice of mother wavelet, and using coefficients that leak future information into training folds.
Learning concept · Not a validated service
Wavelet transforms decompose a time series into components at multiple scales and are useful for isolating trends, seasonal components and transient events. Common error cases include boundary effects, poor choice of mother wavelet, and using coefficients that leak future information into training folds.
A proposed application is pre-processing sensor or energy-consumption series so a downstream forecaster or anomaly detector can use scale-specific features. This extension is not implemented by the supplied starter code.
Assemble a chronological dataset with stable timestamps, handle missing values and create a walk-forward validation split so future data is never used for training.
Apply a discrete wavelet transform to training-series windows, extract coefficients or summary band energies, and keep the transform parameters fixed across folds.
Fit a regression model (for example RandomForest or linear regressor) using lag, rolling and wavelet-derived features, training only on past data at each fold.
Use MAE/RMSE and prediction-interval coverage, inspect large errors by scale, and check for boundary-related artefacts in wavelet coefficients.
The supplied starter builds a synthetic daily series with trend, sinusoidal seasonality and Gaussian noise, creates lag and rolling-mean features, fits a RandomForestRegressor on those features, and prints MAE and a small table of forecasts. It does not compute any wavelet transform or wavelet-derived features.
for lag in [1, 7, 14]:
series[f"lag_{lag}"] = series["value"].shift(lag)
series["rolling_7"] = series["value"].shift(1).rolling(7).mean()
series = series.dropna()
feature_cols = ["lag_1", "lag_7", "lag_14", "rolling_7"]
train = series.iloc[:-30]
test = series.iloc[-30:]
model = RandomForestRegressor(n_estimators=300, random_state=42)
model.fit(train[feature_cols], train["value"])
forecast = model.predict(test[feature_cols])The code uses only lag and rolling statistics and fits a RandomForest; it includes no wavelet transform, no wavelet coefficients or band energies, and the data is a small synthetic series rather than a domain dataset.
Proposed extension: compute discrete wavelet transforms on rolling windows, add band-energy or coarse/fine coefficients as features, and compare forecasting error and interval coverage against the lag-only baseline.
This is a potential application pathway, not a delivered product. The supplied starter does not implement this service or validate it with real users.
Networkers Home runs this topic inside its AI Engineer Course, with placement support and hands-on labs.