我们有兴趣在 OpenMDAO 中实现的飞机设计过程中使用代理模型。基本上，我们希望使用空气动力学代码（例如我们的目标中的 VSPaero）来生成数据库（使用 DOE），然后构建将在设计过程中使用的代理。看起来您的建议 2）在openMDAO 中使用 MOE ，我们还希望访问要在完整设计问题中使用的代理的“梯度”信息。
我们从您在 嵌套问题中提供的代码开始， 并尝试使用简化的空气动力学组件构建模型案例。示例代码如下（使用克里金法），我们有两个问题要完成它：
- 如果我们想使用代理梯度信息，我们需要在我们的组件中实现一个“线性化”函数：我想我们应该使用问题的“calc_gradient”函数来做到这一点。这样对吗 ？
- 在我们的示例代码中，每次调用组件时都会进行训练，这不是很有效：有没有办法只调用一次或仅在较大问题的 setup() 之后进行代理训练（飞机设计在我们的例子中）？
这是代码（抱歉有点长）：
from openmdao.api import IndepVarComp, Group, Problem, ScipyOptimizer, ExecComp, DumpRecorder, Component, NLGaussSeidel,ScipyGMRES, Newton,SqliteRecorder,MetaModel, \
KrigingSurrogate, FloatKrigingSurrogate
from openmdao.drivers.latinhypercube_driver import LatinHypercubeDriver, OptimizedLatinHypercubeDriver
from openmdao.solvers.solver_base import NonLinearSolver
import numpy as np
import sys
alpha_test = np.array([0.56, 0.24, 0.30, 0.32, 0.20])
eta_test = np.array([-0.30, -0.14, -0.19, -0.18, -0.12])
num_elem = len(alpha_test)
class SysAeroSurrogate(Component):
""" Simulates the presence of an aero surrogate mode using linear aerodynamic model """
""" coming from pymission code """
""" https://github.com/OpenMDAO-Plugins/pyMission/blob/master/src/pyMission/aerodynamics.py """
def __init__(self, num_elem=1):
super(SysAeroSurrogate, self).__init__()
self.add_param('alpha', 0.5)
self.add_param('eta', -0.33)
self.add_param('AR', 0.0)
self.add_param('oswald', 0.0)
self.add_output('CL', val=0.0)
self.add_output('CD', val=0.0) ## Drag Coefficient
def solve_nonlinear(self, params, unknowns, resids):
""" Compute lift and drag coefficient using angle of attack and tail
rotation angles. Linear aerodynamics is assumed."""
alpha = params['alpha']
eta = params['eta']
aspect_ratio = params['AR']
oswald = params['oswald']
lift_c0 = 0.30
lift_ca = 6.00
lift_ce = 0.27
drag_c0 = 0.015
unknowns['CL'] = lift_c0 + lift_ca*alpha*1e-1 + lift_ce*eta*1e-1
unknowns['CD'] = (drag_c0 + (unknowns['CL'])**2 /(np.pi * aspect_ratio * oswald))/1e-1
class SuroMM(Group):
def __init__(self):
super(SuroMM, self).__init__()
#kriging
AeroMM = self.add("AeroMM", MetaModel())
AeroMM.add_param('alpha', val=0.)
AeroMM.add_param('eta', val=0.)
AeroMM.add_output('CL_MM', val=0., surrogate=FloatKrigingSurrogate())
AeroMM.add_output('CD_MM', val=0., surrogate=FloatKrigingSurrogate())
class SurrogateAero(Component):
def __init__(self):
super(SurrogateAero, self).__init__()
## Inputs to this subprob
self.add_param('alpha', val=0.5*np.ones(num_elem)) ## Angle of attack
self.add_param('eta', val=0.5*np.ones(num_elem)) ## Tail rotation angle
self.add_param('AR', 0.0)
self.add_param('oswald', 0.0)
## Unknowns for this sub prob
self.add_output('CD', val=np.zeros(num_elem))
self.add_output('CL', val=np.zeros(num_elem))
#####
self.problem = prob = Problem()
prob.root = Group()
prob.root.add('d1', SuroMM(), promotes=['*'])
prob.setup()
#### training of metamodel
prob['AeroMM.train:alpha'] = DOEX1
prob['AeroMM.train:eta'] = DOEX2
prob['AeroMM.train:CL_MM'] = DOEY1
prob['AeroMM.train:CD_MM'] =DOEY2
def solve_nonlinear(self, params, unknowns, resids):
CL_temp=np.zeros(num_elem)
CD_temp=np.zeros(num_elem)
prob = self.problem
# Pass values into our problem
for i in range(len(params['alpha'])):
prob['AeroMM.alpha'] = params['alpha'][i]
prob['AeroMM.eta'] = params['eta'][i]
# Run problem
prob.run()
CL_temp[i] = prob['AeroMM.CL_MM']
CD_temp[i] = prob['AeroMM.CD_MM']
# Pull values from problem
unknowns['CL'] = CL_temp
unknowns['CD'] = CD_temp
if __name__ == "__main__":
###### creation of database with DOE #####
top = Problem()
root = top.root = Group()
root.add('comp', SysAeroSurrogate(), promotes=['*'])
root.add('p1', IndepVarComp('alpha', val=0.50), promotes=['*'])
root.add('p2', IndepVarComp('eta',val=0.50), promotes=['*'])
root.add('p3', IndepVarComp('AR', 10.), promotes=['*'])
root.add('p4', IndepVarComp('oswald', 0.92), promotes=['*'])
top.driver = OptimizedLatinHypercubeDriver(num_samples=16, seed=0, population=20, generations=4, norm_method=2)
top.driver.add_desvar('alpha', lower=-5.0*(np.pi/180.0)*1e-1, upper=15.0*(np.pi/180.0)*1e-1)
top.driver.add_desvar('eta', lower=-5.0*(np.pi/180.0)*1e-1, upper=15.0*(np.pi/180.0)*1e-1)
top.driver.add_objective('CD')
recorder = SqliteRecorder('Aero')
recorder.options['record_params'] = True
recorder.options['record_unknowns'] = True
recorder.options['record_resids'] = False
recorder.options['record_metadata'] = False
top.driver.add_recorder(recorder)
top.setup()
top.run()
import sqlitedict
db = sqlitedict.SqliteDict( 'Aero', 'openmdao' )
print( list( db.keys() ) )
DOEX1 = []
DOEX2 = []
DOEY1 = []
DOEY2 = []
for i in list(db.keys()):
data = db[i]
p = data['Parameters']
DOEX1.append(p['comp.alpha'])
DOEX2.append(p['comp.eta'])
p = data['Unknowns']
DOEY1.append(p['CL'])
DOEY2.append(p['CD'])
################ use of surrogate model ######
prob2 = Problem(root=Group())
prob2.root.add('SurrAero', SurrogateAero(), promotes=['*'])
prob2.root.add('v1', IndepVarComp('alpha', val=alpha_test), promotes=['*'])
prob2.root.add('v2', IndepVarComp('eta',val=eta_test), promotes=['*'])
prob2.setup()
prob2.run()
print'CL predicted:', prob2['CL']
print'CD predicted:', prob2['CD']