moving-average

C++ implementation

// Based on the Arduino Moving Average Library
// https://github.com/JChristensen/movingAvg


node {
    // Internal state variables defined at this level persists across evaluations

    int m_interval;     // number of data points for the moving average
    int m_nbrReadings;  // number of readings
    long m_sum;         // sum of the m_readings array
    int m_next;         // index to the next reading
    int *m_readings;    // pointer to the dynamically allocated interval array

    // initialize - allocate the interval array
    void init()
    {
        m_readings = new int[m_interval];
    }

    // add a new reading and return the new moving average
    int reading(int newReading)
    {
        // add each new data point to the sum until the m_readings array is filled
        if (m_nbrReadings < m_interval)
        {
            ++m_nbrReadings;
            m_sum = m_sum + newReading;
        }
        // once the array is filled, subtract the oldest data point and add the new one
        else
        {
            m_sum = m_sum - m_readings[m_next] + newReading;
        }

        m_readings[m_next] = newReading;
        if (++m_next >= m_interval) m_next = 0;
        return (m_sum + m_nbrReadings / 2) / m_nbrReadings;
    }

    // just return the current moving average
    int getAvg()
    {
        return (m_sum + m_nbrReadings / 2) / m_nbrReadings;
    }

    // start the moving average over again
    void reset()
    {
        m_nbrReadings = 0;
        m_sum = 0;
        m_next = 0;
    }


    void evaluate(Context ctx) {

        if (isSettingUp()) {
            // This run once
            m_interval = getValue<input_NUM>(ctx);
            init();
        }

        if (isInputDirty<input_RST>(ctx))
            reset();

        emitValue<output_OUT>(ctx, reading(getValue<input_IN>(ctx)));
    }
}