def test(self):
"""
A simple example to compute the resultant force on an aircraft and demonstrate the AddSubtract component
"""
import numpy as np
#from openmdao.api import Problem, Group, IndepVarComp
from openconcept.utilities.math.add_subtract_comp import AddSubtractComp
from openmdao.utils.assert_utils import assert_rel_error
n = 3
p = Problem(model=Group())
ivc = IndepVarComp()
#the vector represents forces at 3 analysis points (rows) in 2 dimensional plane (cols)
ivc.add_output(name='thrust', shape=(n, 2), units='kN')
ivc.add_output(name='drag', shape=(n, 2), units='kN')
ivc.add_output(name='lift', shape=(n, 2), units='kN')
ivc.add_output(name='weight', shape=(n, 2), units='kN')
p.model.add_subsystem(
name='ivc',
subsys=ivc,
promotes_outputs=['thrust', 'drag', 'lift', 'weight'])
#construct an adder/subtracter here. create a relationship through the add_equation method
adder = AddSubtractComp()
adder.add_equation('total_force',
input_names=['thrust', 'drag', 'lift', 'weight'],
vec_size=n,
length=2,
scaling_factors=[1, -1, 1, -1],
units='kN')
#note the scaling factors. we assume all forces are positive sign upstream
p.model.add_subsystem(name='totalforcecomp', subsys=adder)
p.model.connect('thrust', 'totalforcecomp.thrust')
p.model.connect('drag', 'totalforcecomp.drag')
p.model.connect('lift', 'totalforcecomp.lift')
p.model.connect('weight', 'totalforcecomp.weight')
p.setup()
#set thrust to exceed drag, weight to equal lift for this scenario
p['thrust'][:, 0] = [500, 600, 700]
p['drag'][:, 0] = [400, 400, 400]
p['weight'][:, 1] = [1000, 1001, 1002]
p['lift'][:, 1] = [1000, 1000, 1000]
p.run_model()
# print(p.get_val('totalforcecomp.total_force', units='kN'))
# Verify the results
expected_i = np.array([[100, 200, 300], [0, -1, -2]]).T
assert_rel_error(self,
p.get_val('totalforcecomp.total_force', units='kN'),
expected_i)
def promote_add(self,
sources,
prom_name,
promoted_sources=[],
factors=None,
vec_size=1,
units=None,
length=1,
val=1.0,
res_units=None,
desc='',
lower=None,
upper=None,
ref=1.0,
ref0=0.0,
res_ref=None):
"""Helper function called during setup"""
add_index = self._n_auto_comps
self._n_auto_comps += 1
adder = AddSubtractComp()
n_inputs = len(sources) + len(promoted_sources)
if factors is None:
factors = np.ones(n_inputs)
adder.add_equation(
output_name=prom_name,
input_names=['_temp' + str(i) for i in range(n_inputs)],
scaling_factors=factors,
vec_size=vec_size,
units=units,
length=length,
val=val,
res_units=res_units,
desc=desc,
lower=lower,
upper=upper,
ref=ref,
ref0=ref0,
res_ref=res_ref)
adder_name = 'add' + str(add_index)
prom_in = []
for i, promoted_source in enumerate(promoted_sources):
prom_in.append(('_temp' + str(i + len(sources)), promoted_source))
self.add_subsystem(adder_name,
adder,
promotes_inputs=prom_in,
promotes_outputs=['*'])
for i, source in enumerate(sources):
self.connect(source, adder_name + '._temp' + str(i))