External code incompatibility with metadata? - openmdao

Question

If I use the same setup with metadata for an external code component and explicit component it seems to fail with the externalcode comp. The code below has both of the component. As is there is no error, if i comment out the explicit component part I get an error :
comp = GFWrapper(DVLO=np.array(DVLIST))
TypeError: init() got an unexpected keyword argument 'DVLO'
import numpy as np
import json as js
import re,sys,subprocess,os
from openmdao.api import Problem, Group, IndepVarComp
from openmdao.api import ScipyOptimizeDriver
from openmdao.api import ExternalCode
class GFWrapper(ExternalCode):
def initialize(self):
self.metadata.declare('DVLO', types=np.ndarray)
def setup(self):
DVLO = self.metadata['DVLO']
for dv in DVLO:
self.add_input(dv)
self.add_output('OBJECTIVE')
self.input_file = 'GFWrapper_input.dat'
self.output_file = 'GFWrapper_output.dat'
self.options['external_input_files'] = [self.input_file,]
self.options['external_output_files'] = [self.output_file,]
self.options['command'] = [
'python', 'run.py', self.input_file, self.output_file
]
#self.declare_partials(of='*', wrt='*', method='fd')
for dv in DVLO:
self.declare_partials(of='OBJECTIVE', wrt=dv, method='fd')
def compute(self, inputs, outputs):
DVLO = self.metadata['DVLO']
# generate the input file for the external code
outF = open(self.input_file, "w")
for dv in DVLO:
outF.write(inputs[dv])
print(dv,inputs[dv])
outF.write("\n")
outF.close()
# the parent compute function actually runs the external code
super(GFWrapper, self).compute(inputs, outputs)
# parse the output file from the external code
file_contents=np.loadtxt(self.output_file)
outputs['OBJECTIVE'] = file_contents[0]
from openmdao.api import ExplicitComponent
#
class GFWrapper(ExplicitComponent):
def initialize(self):
self.metadata.declare('DVLO', types=np.ndarray)
def setup(self):
DVLO = self.metadata['DVLO']
for dv in DVLO:
self.add_input(dv)
self.add_output('OBJECTIVE')
#self.declare_partials(of='*', wrt='*', method='fd')
for dv in DVLO:
self.declare_partials(of='OBJECTIVE', wrt=dv, method='fd')
def compute(self, inputs, outputs):
DVLO = self.metadata['DVLO']
powetemp = 0
for dv in DVLO:
powetemp += inputs[dv]
outputs['OBJECTIVE'] = powetemp
#
DVLIST=['DV1','DV2']
DVMIN =[2,11]
DVMAX =[3,12]
InitDVVal=[3,5]
nr_of_desvar=len(DVLIST)
top = Problem()
top.model = model = Group()
" Introduce independent variables later will be design variables (optimization parameters) "
inputs_comp = IndepVarComp()
for i in range(nr_of_desvar):
inputs_comp.add_output(DVLIST[i],InitDVVal[i])
" Add components/subsystems to the Group-model- "
model.add_subsystem('inputs_comp', inputs_comp)
comp = GFWrapper(DVLO=np.array(DVLIST))
model.add_subsystem('GFWrapper', comp)

Answer 1

This is a bug in OpenMDAO version 2.2. The error occurs because we didn't include **kwargs in the init statement for ExternalCode. We intend to fix this for V2.3, but in the meantime, you can work around for your GFWrapper component by adding an init statement like this:
class GFWrapper(ExternalCode):
def __init__(self, **kwargs):
super(GFWrapper, self).__init__()
self.metadata.update(kwargs)