Simple implementation of python code (using numpy) for rounding numbers using probabilistic rounding on the last digit. Should be able to handle pos and neg values but not arrays.

numpyfloatRandRound.py

def truncFloat(x,dp):
    '''Truncates a numpy float to given decimal places (dp)'''
    return np.trunc(x * 10 ** dp) / 10 ** dp

def probRound(x, dp):
    '''Rounds float to given decimal places (dp), with
       last digit round done on a probablistic basis.'''
    
    xTrunc = truncFloat(x, dp)  # Truncate to dp figures
    xrem = x - xTrunc  # find remainder of truncation
    
    p = np.abs(xrem) * 10 ** dd  # prob of rounding up based on trunc remainder
    if np.random.uniform(0,1) < p:
        xout = xTrunc + np.sign(x) * 10 ** -dd
    else:
        xout = xTrunc
        
    return xout