Gesture notebooks: std feature mislabeled "std(mag.max())" (it computes std(mag))

[jonfroehlich]

Found in the #16 correctness/prose/comments audit (verified).

The standard-deviation feature is given a wrong column name in both gesture notebooks. The value computed is np.std(trial.accel.mag) (std of the magnitude signal), but the name appended is "std(mag.max())":

features.append(np.std(trial.accel.mag))
feature_names.append("std(mag.max())")   # <-- should be "std(mag)"

mag.max() is a single scalar (its std would be 0/NaN), so the name is simply wrong and misleads every feature table, correlation heatmap, and classification report that displays it.

Locations

• Projects/GestureRecognizer/GestureRecognizer-FeatureBased.ipynb (the extract_features_from_gesture_set cell)
• Projects/GestureRecognizer/Feature Selection and Hyperparameter Tuning.ipynb (its copy of the same function)

Fix

Rename to "std(mag)" (or "mag.std()") in both.