Time-level hysteresis

hyst.py

def hyst(x, thr1, thr2, thr1_time = 0, thr2_time = 0, initial = False):
    def level_hysteresis(sig, thr):
        when_over = sig > thr
        when_under = 1-when_over
        where_under = np.where(when_over == 0)[0]
        
        over_cumsum = np.cumsum(when_over)
        under_cumsum = np.cumsum(when_under)
        return np.maximum(0, over_cumsum - over_cumsum[where_under[under_cumsum-1]])
    
    over = level_hysteresis(x, thr2)
    under = level_hysteresis(-x, -thr1)
    level = over-under
    
    hi = level > thr2_time
    lo = level < -thr1_time
    lo_or_hi = lo | hi
    ind = np.nonzero(lo_or_hi)[0]
    cnt = np.cumsum(lo_or_hi)

    return np.where(cnt, hi[ind[cnt-1]], initial), level

if __name__ == "__main__":
    import numpy as np
    from matplotlib import pyplot as plt
    
    from typing import List

    thr1 = 0.5
    thr1_time = 0
    thr2 = 1
    thr2_time = 0
    
    x = np.linspace(0, 5, 1000)
    y = np.sin(x)+0.7*np.sin(3*x)
    
    val_histeresis = hyst(y, thr1, thr2, thr1_time=10, thr2_time=10)
    
    f, ax = plt.subplots(3, 1, sharex=True)
    
    ax: List[plt.axes]
    
    ax[0].plot(x, y)
    ax[0].hlines(thr1, x[0], x[-1])
    ax[0].hlines(thr2, x[0], x[-1])
    ax[0].grid()
    
    ax[1].plot(x, val_histeresis[0])
    ax[1].grid()
    
    ax[2].plot(x, val_histeresis[1])