def test_dymola_export_import(self):
"""
Test for export and import the result file on Dymola textual format.
"""
vdp = self.vdp
# Initialize the mesh
n_e = 50 # Number of elements
hs = N.ones(n_e) * 1. / n_e # Equidistant points
n_cp = 3
# Number of collocation points in each element
# Create an NLP object
nlp = ipopt.NLPCollocationLagrangePolynomials(vdp, n_e, hs, n_cp)
# Create an Ipopt NLP object
nlp_ipopt = ipopt.CollocationOptimizer(nlp)
# Solve the optimization problem
nlp_ipopt.opt_coll_ipopt_solve()
# Get the result
p_opt, traj = nlp.get_result()
# Write to file
nlp.export_result_dymola()
# Load the file we just wrote
res = ResultDymolaTextual(self.fname[:-len('.jmu')] + '_result.txt')
# Check that one of the trajectories match.
assert max(N.abs(traj[:, 3] - res.get_variable_data('x1').x)) < 1e-12
# Check that the value of the cost function is correct
assert N.abs(p_opt[0] - 2.2811587) < 1e-5
def setUp(self):
"""Test setUp. Load the test model."""
cpath_vdp = "VDP_pack.VDP_Opt_Min_Time"
fname_vdp = cpath_vdp.replace('.','_',1)
self.fname_vdp = fname_vdp
self.vdp = JMUModel(fname_vdp+'.jmu')
# Initialize the mesh
n_e = 100 # Number of elements
hs = N.ones(n_e)*1./n_e # Equidistant points
self.hs = hs
n_cp = 3; # Number of collocation points in each element
# Create an NLP object
self.nlp = ipopt.NLPCollocationLagrangePolynomials(
self.vdp,n_e,hs,n_cp)
self.nlp_ipopt = ipopt.CollocationOptimizer(self.nlp)
def run_demo(with_plots=True):
"""
Model predicitve control of the Hicks-Ray CSTR reactor. This example
demonstrates how to use the blocking factor feature of the collocation
algorithm.
This example also shows how to use classes for initialization, simulation
and optimization directly rather than calling then through the high-level
classes 'initialialize', 'simulate' and 'optimize'.
"""
curr_dir = os.path.dirname(os.path.abspath(__file__))
# Compile the stationary initialization model into a JMU
jmu_name = compile_jmu("CSTR.CSTR_Init",
os.path.join(curr_dir, "files", "CSTR.mop"))
# Load a JMUModel instance
init_model = JMUModel(jmu_name)
# Create DAE initialization object.
init_nlp = NLPInitialization(init_model)
# Create an Ipopt solver object for the DAE initialization system
init_nlp_ipopt = InitializationOptimizer(init_nlp)
def compute_stationary(Tc_stat):
init_model.set('Tc', Tc_stat)
# Solve the DAE initialization system with Ipopt
init_nlp_ipopt.init_opt_ipopt_solve()
return (init_model.get('c'), init_model.get('T'))
# Set inputs for Stationary point A
Tc_0_A = 250
c_0_A, T_0_A = compute_stationary(Tc_0_A)
# Print some data for stationary point A
print(' *** Stationary point A ***')
print('Tc = %f' % Tc_0_A)
print('c = %f' % c_0_A)
print('T = %f' % T_0_A)
# Set inputs for Stationary point B
Tc_0_B = 280
c_0_B, T_0_B = compute_stationary(Tc_0_B)
# Print some data for stationary point B
print(' *** Stationary point B ***')
print('Tc = %f' % Tc_0_B)
print('c = %f' % c_0_B)
print('T = %f' % T_0_B)
jmu_name = compile_jmu("CSTR.CSTR_Opt_MPC",
os.path.join(curr_dir, "files", "CSTR.mop"))
cstr = JMUModel(jmu_name)
cstr.set('Tc_ref', Tc_0_B)
cstr.set('c_ref', c_0_B)
cstr.set('T_ref', T_0_B)
cstr.set('cstr.c_init', c_0_A)
cstr.set('cstr.T_init', T_0_A)
# Initialize the mesh
n_e = 50 # Number of elements
hs = N.ones(n_e) * 1. / n_e # Equidistant points
n_cp = 3
# Number of collocation points in each element
# Create an NLP object
# The length of the optimization interval is 50s and the
# number of elements is 50, which gives a blocking factor
# vector of 2*ones(n_e/2) to match the sampling interval
# of 2s.
nlp = ipopt.NLPCollocationLagrangePolynomials(cstr,
n_e,
hs,
n_cp,
blocking_factors=2 *
N.ones(n_e / 2, dtype=N.int))
# Create an Ipopt NLP object
nlp_ipopt = ipopt.CollocationOptimizer(nlp)
nlp_ipopt.opt_coll_ipopt_set_int_option("max_iter", 500)
h = 2. # Sampling interval
T_final = 180. # Final time of simulation
t_mpc = N.linspace(0, T_final, T_final / h + 1)
n_samples = N.size(t_mpc)
ref_mpc = N.zeros(n_samples)
ref_mpc[0:3] = N.ones(3) * Tc_0_A
ref_mpc[3:] = N.ones(n_samples - 3) * Tc_0_B
cstr.set('cstr.c_init', c_0_A)
cstr.set('cstr.T_init', T_0_A)
# Compile the simulation model into a DLL
jmu_name = compile_jmu("CSTR.CSTR",
os.path.join(curr_dir, "files", "CSTR.mop"))
# Load a model instance into Python
sim_model = JMUModel(jmu_name)
sim_model.set('c_init', c_0_A)
sim_model.set('T_init', T_0_A)
global cstr_mod
global cstr_sim
cstr_mod = JMIDAE(sim_model) # Create an Assimulo problem
cstr_sim = IDA(cstr_mod) # Create an IDA solver
i = 0
if with_plots:
plt.figure(4)
plt.clf()
for t in t_mpc[0:-1]:
Tc_ref = ref_mpc[i]
c_ref, T_ref = compute_stationary(Tc_ref)
cstr.set('Tc_ref', Tc_ref)
cstr.set('c_ref', c_ref)
cstr.set('T_ref', T_ref)
# Solve the optimization problem
nlp_ipopt.opt_coll_ipopt_solve()
# Write to file.
nlp.export_result_dymola()
# Load the file we just wrote to file
res = ResultDymolaTextual('CSTR_CSTR_Opt_MPC_result.txt')
# Extract variable profiles
c_res = res.get_variable_data('cstr.c')
T_res = res.get_variable_data('cstr.T')
Tc_res = res.get_variable_data('cstr.Tc')
# Get the first Tc sample
Tc_ctrl = Tc_res.x[0]
# Set the value to the model
sim_model.set('Tc', Tc_ctrl)
# Simulate
cstr_sim.simulate(t_mpc[i + 1])
t_T_sim = cstr_sim.t_sol
# Set terminal values of the states
cstr.set('cstr.c_init', cstr_sim.y[0])
cstr.set('cstr.T_init', cstr_sim.y[1])
sim_model.set('c_init', cstr_sim.y[0])
sim_model.set('T_init', cstr_sim.y[1])
if with_plots:
plt.figure(4)
plt.subplot(3, 1, 1)
plt.plot(t_T_sim, N.array(cstr_sim.y_sol)[:, 0], 'b')
plt.subplot(3, 1, 2)
plt.plot(t_T_sim, N.array(cstr_sim.y_sol)[:, 1], 'b')
if t_mpc[i] == 0:
plt.subplot(3, 1, 3)
plt.plot([t_mpc[i], t_mpc[i + 1]], [Tc_ctrl, Tc_ctrl], 'b')
else:
plt.subplot(3, 1, 3)
plt.plot([t_mpc[i], t_mpc[i], t_mpc[i + 1]],
[Tc_ctrl_old, Tc_ctrl, Tc_ctrl], 'b')
Tc_ctrl_old = Tc_ctrl
i = i + 1
assert N.abs(Tc_ctrl - 279.097186038194) < 1e-6
assert N.abs(N.array(cstr_sim.y_sol)[:, 0][-1] - 350.89028563) < 1e-6
assert N.abs(N.array(cstr_sim.y_sol)[:, 1][-1] - 283.15229948) < 1e-6
if with_plots:
plt.figure(4)
plt.subplot(3, 1, 1)
plt.ylabel('c')
plt.plot([0, T_final], [c_0_B, c_0_B], '--')
plt.grid()
plt.subplot(3, 1, 2)
plt.ylabel('T')
plt.plot([0, T_final], [T_0_B, T_0_B], '--')
plt.grid()
plt.subplot(3, 1, 3)
plt.ylabel('Tc')
plt.plot([0, T_final], [Tc_0_B, Tc_0_B], '--')
plt.grid()
plt.xlabel('t')
plt.show()