parallel_ordering.py

import openmdao.api as om

prob = om.Problem()
model = prob.model

model.add_subsystem('p1', om.IndepVarComp('x', 1.0))
model.add_subsystem('p2', om.IndepVarComp('x', 1.0))

parallel = model.add_subsystem('parallel', om.ParallelGroup())
parallel.add_subsystem('c1', om.ExecComp(['y=-2.0*x']))
parallel.add_subsystem('c2', om.ExecComp(['y=5.0*x']))
parallel.connect('c1.y','c2.x')

model.add_subsystem('c3', om.ExecComp(['y=3.0*x1+7.0*x2']))

model.connect("parallel.c1.y", "c3.x1")
model.connect("parallel.c2.y", "c3.x2")

model.connect("p1.x", "parallel.c1.x")
# model.connect("p2.x", "parallel.c2.x")

prob.setup(check=True, mode='fwd')
prob.run_model()

print(prob['c3.y'])