def test_skogestad_half_seborg_ex5_5():
# This is the example from seborg, Example 5.4
num_timeconstants = [-1]
den_timeconstants = [12, 3, 0.2, 0.05]
delay, timeconstants = skogestad_half(num_timeconstants, den_timeconstants, delay=1, order=1)
assert delay == pytest.approx(3.75, 0.01)
assert timeconstants[0] == pytest.approx(13.5)
delay, timeconstants = skogestad_half(num_timeconstants, den_timeconstants, delay=1, order=2)
assert delay == pytest.approx(2.15, 0.01)
assert timeconstants[0] == pytest.approx(12)
assert timeconstants[1] == pytest.approx(3.1)
def test_skogestad_half_skogestad():
# This is the example from
# http://folk.ntnu.no/skoge/presentation/promatch-cybernetica-06/4tuning_short.pdf
num_timeconstants = [-0.3, 0.08]
den_timeconstants = [2, 1, 0.4, 0.2, 0.05, 0.05, 0.05]
delay, timeconstants = skogestad_half(num_timeconstants, den_timeconstants, delay=0, order=1)
assert delay == pytest.approx(1.47, 0.01)
assert timeconstants[0] == pytest.approx(2.5)
delay, timeconstants = skogestad_half(num_timeconstants, den_timeconstants, delay=0, order=2)
assert delay == pytest.approx(0.77, 0.01)
assert timeconstants[0] == pytest.approx(2)
assert timeconstants[1] == pytest.approx(1.2)
def test_skogestad_half_seborg_ex5_4():
# This is the example from seborg, Example 5.4
num_timeconstants = [-0.1]
den_timeconstants = [5, 3, 0.5]
delay, timeconstants = skogestad_half(num_timeconstants, den_timeconstants, delay=0, order=1)
assert delay == pytest.approx(2.1, 0.01)
assert timeconstants[0] == pytest.approx(6.5)
def test_skogestad_half_integercoefficients():
# this used to break with earlier versions of the code
num_timeconstants = [10]
den_timeconstants = [20, 5, 5]
delay, timeconstants = skogestad_half(num_timeconstants,
den_timeconstants,
delay=10,
order=1)
assert delay == pytest.approx(7.5, 0.01)
assert timeconstants[0] == pytest.approx(22.5)