def f_ref(x):
    idx = (x // 1)
    if (idx <= 0):
        return branches[0](x)
    elif (idx == 1):
        return branches[1](x)
    else:
        return branches[2](x)
def f_ref(x):
    idx = (x // 1)
    if (idx <= 0):
        return branches[0](x)
    elif (idx == 1):
        return branches[1](x)
    else:
        return branches[2](x)