def pi(x, b):
    s_1 = ((0.5 * b[5]) / ((abs(b[2]) * b[0]) + (abs((1 - abs(b[2]))) * b[1])))
    s_2 = ((abs(b[2]) * b[0]) * erf((((b[6] - x) - b[3]) / (sqrt(2) * b[0]))))
    s_3 = ((abs(b[2]) * b[0]) * erf(((((- b[6]) - x) - b[3]) / (sqrt(2) * b[0]))))
    s_4 = ((abs((1 - abs(b[2]))) * b[1]) * erf((((b[6] - x) - b[3]) / (sqrt(2) * b[1]))))
    s_5 = ((abs((1 - abs(b[2]))) * b[1]) * erf(((((- b[6]) - x) - b[3]) / (sqrt(2) * b[1]))))
    return ((s_1 * (((s_2 - s_3) + s_4) - s_5)) + b[4])
def pi(x, b):
    s_1 = ((0.5 * b[5]) / ((abs(b[2]) * b[0]) + (abs((1 - abs(b[2]))) * b[1])))
    s_2 = ((abs(b[2]) * b[0]) * erf((((b[6] - x) - b[3]) / (sqrt(2) * b[0]))))
    s_3 = ((abs(b[2]) * b[0]) * erf(((((- b[6]) - x) - b[3]) / (sqrt(2) * b[0]))))
    s_4 = ((abs((1 - abs(b[2]))) * b[1]) * erf((((b[6] - x) - b[3]) / (sqrt(2) * b[1]))))
    s_5 = ((abs((1 - abs(b[2]))) * b[1]) * erf(((((- b[6]) - x) - b[3]) / (sqrt(2) * b[1]))))
    return ((s_1 * (((s_2 - s_3) + s_4) - s_5)) + b[4])