movingAverage function

List<double?> movingAverage(List<double> data, { required int window, bool center = false, })

Computes the simple moving average of a series.

data is the input time series. window is the size of the moving window. center if true, centers the window around each point (default: false).

Returns a list of the same length as data, with null for positions where the window doesn't fit (at the edges).

Implementation

List<double?> movingAverage(
  List<double> data, {
  required int window,
  bool center = false,
}) {
  if (window < 1) {
    throw ArgumentError('Window size must be at least 1');
  }
  if (data.isEmpty) {
    return [];
  }

  final result = List<double?>.filled(data.length, null);

  if (center) {
    final halfWindow = window ~/ 2;
    for (int i = halfWindow; i < data.length - (window - 1 - halfWindow); i++) {
      double sum = 0;
      for (int j = i - halfWindow; j < i - halfWindow + window; j++) {
        sum += data[j];
      }
      result[i] = sum / window;
    }
  } else {
    // Trailing window
    for (int i = window - 1; i < data.length; i++) {
      double sum = 0;
      for (int j = i - window + 1; j <= i; j++) {
        sum += data[j];
      }
      result[i] = sum / window;
    }
  }

  return result;
}