Learning Forum

[gangin2]

I have python code that does topology optimization inverse design and it works for an older version of lumerical (2023 R2.3) on our computer, but it fails when I use it for the latest version, 2025 R1.  The error is below:

CONFIGURATION FILE {'root': 'C:\\Program Files\\ANSYS Inc\\v251\\Lumerical\\api\\python', 'lumapi': 'C:\\Program Files\\ANSYS Inc\\v251\\Lumerical\\api\\python'}
Initializing super optimization
Checking for one forward simulation :   One forward simulation is in progress
One forward simulation is in progress
One forward simulation is in progress
Wavelength range of source object will be superseded by the global settings.
Traceback (most recent call last):
  File "C:\Users\LAB1\Documents\Inverse Design\cross_split\cross_split_opt.py", line 93, in
    runSim(initial_cond, eps_min, eps_max, x_pos, y_pos, filter_R*1e-9, working_dir)
  File "C:\Users\LAB1\Documents\Nick\Inverse Design\cross_split\cross_split_opt.py", line 64, in runSim
    opt.run(working_dir = working_dir)
  File "C:\Program Files\ANSYS Inc\v251\Lumerical\api\python\lumopt\optimization.py", line 471, in run
    self.initialize(working_dir=working_dir)
  File "C:\Program Files\ANSYS Inc\v251\Lumerical\api\python\lumopt\optimization.py", line 361, in initialize
    self.optimizer.initialize(start_params=start_params,
  File "C:\Program Files\ANSYS Inc\v251\Lumerical\api\python\lumopt\optimizers\optimizer.py", line 100, in initialize
    self.reset_start_params(start_params, self.scale_initial_gradient_to)
  File "C:\Program Files\ANSYS Inc\v251\Lumerical\api\python\lumopt\optimizers\optimizer.py", line 108, in reset_start_params
    self.auto_detect_scaling(scale_initial_gradient_to)
  File "C:\Program Files\ANSYS Inc\v251\Lumerical\api\python\lumopt\optimizers\optimizer.py", line 115, in auto_detect_scaling
    gradients = self.callable_jac(params)
  File "C:\Program Files\ANSYS Inc\v251\Lumerical\api\python\lumopt\optimizers\minimizer.py", line 34, in callable_jac_local
    fom_gradients = callable_jac(params_over_scaling_factor) / self.scaling_factor
  File "C:\Program Files\ANSYS Inc\v251\Lumerical\api\python\lumopt\optimization.py", line 223, in callable_jac
    canMakeAdjointSim = canMakeAdjointSim & opt.fom.can_make_adjoint_sim(opt.sim)
AttributeError: 'Optimization' object has no attribute 'sim'
>>>

 

Any guidance on what changes are necessary to get it to run on the latest version would be appreciated.

[Dev]

Hello,

Sorry for the delayed response.

Could you please let me know if the Python code is from a Lumerical Application Gallery example or if you wrote it yourself?

Seems like the the Optimization object no longer possesses the sim attribute .

A solution can be modify your code to align with the new API structure, including setting attributes like sim manually.

 

[gangin2]

The pyhton code is written myself.  I based it off of https://optics.ansys.com/hc/en-us/articles/1500007188582-Topology-Optimization-of-a-4-channel-wavelength-demultiplexer-2D-TE.  But I can successfully run the example without issue.

I think my code is very similar to the example and I am not sure where I am using the sim attribute.  Can you help me identify where I am doing this?  Here is my optimization script:

######## IMPORTS ########

# General purpose imports

import numpy as np

import os

import sys

import scipy as sp

 

# Optimization specific imports

from lumopt import CONFIG

from lumopt.geometries.topology import TopologyOptimization2D, TopologyOptimization3DLayered

from lumopt.utilities.load_lumerical_scripts import load_from_lsf

from lumopt.figures_of_merit.modematch import ModeMatch

from lumopt.optimization import Optimization

from lumopt.optimizers.generic_optimizers import ScipyOptimizers

from lumopt.utilities.wavelengths import Wavelengths

 

sys.path.append(os.path.dirname(__file__))

from cross_split_base import cross_split_base_init_

cross_split_base = cross_split_base_init_

 

cur_path = os.path.dirname(os.path.abspath(__file__))

 

######## RUNS TOPOLOGY OPTIMIZATION OF A 2D STRUCTURE ########

def runSim(params, eps_min, eps_max, x_pos, y_pos, filter_R, working_dir):

 

    ######## DEFINE A 2D TOPOLOGY OPTIMIZATION REGION ########

    geometry = TopologyOptimization2D(params=params, eps_min=eps_min, eps_max=eps_max, x=x_pos, y=y_pos, z=0, filter_R=filter_R, min_feature_size=filter_R)

    

    ######## DEFINE FIGURE OF MERIT ########

    # The base simulation script defines a field monitor named 'fom' at the point where we want to modematch to the fundamental TE mode

    fom0 = ModeMatch(monitor_name = 'fom 0',

                    mode_number = 'fundamental TE mode',

                    direction = 'Backward',

                    target_T_fwd = lambda wl: 0.25*np.ones(wl.size),

                    norm_p = 1)    

    fom1 = ModeMatch(monitor_name = 'fom 1',

                    mode_number = 'fundamental TE mode',

                    direction = 'Forward',

                    target_T_fwd = lambda wl: 0.25*np.ones(wl.size),

                    norm_p = 1) 

    fom2 = ModeMatch(monitor_name = 'fom 2',

                    mode_number = 'fundamental TE mode',

                    direction = 'Forward',

                    target_T_fwd = lambda wl: 0.25*np.ones(wl.size),

                    norm_p = 1) 

    fom3 = ModeMatch(monitor_name = 'fom 3',

                    mode_number = 'fundamental TE mode',

                    direction = 'Backward',

                    target_T_fwd = lambda wl: 0.25*np.ones(wl.size),

                    norm_p = 1) 

    ######## DEFINE OPTIMIZATION ALGORITHM ########

    optimizer = ScipyOptimizers(max_iter=50, method='L-BFGS-B', scaling_factor=1, pgtol=1e-6, ftol=1e-5, scale_initial_gradient_to=0.25)

 

    ######## SETTING UP THE OPTIMIZER ########

    wavelengths = Wavelengths(start = 1545e-9, stop = 1555e-9, points = 11)

    opt0 = Optimization(base_script=cross_split_base, wavelengths = wavelengths, fom=fom0, geometry=geometry, optimizer=optimizer, use_deps=False, use_var_fdtd = False, hide_fdtd_cad=False, plot_history=True, store_all_simulations=False, save_global_index=True)

    opt1 = Optimization(base_script=cross_split_base, wavelengths = wavelengths, fom=fom1, geometry=geometry, optimizer=optimizer, use_deps=False, use_var_fdtd = False, hide_fdtd_cad=False, plot_history=True, store_all_simulations=False, save_global_index=False)

    opt2 = Optimization(base_script=cross_split_base, wavelengths = wavelengths, fom=fom2, geometry=geometry, optimizer=optimizer, use_deps=False, use_var_fdtd = False, hide_fdtd_cad=False, plot_history=True, store_all_simulations=False, save_global_index=False)

    opt3 = Optimization(base_script=cross_split_base, wavelengths = wavelengths, fom=fom3, geometry=geometry, optimizer=optimizer, use_deps=False, use_var_fdtd = False, hide_fdtd_cad=False, plot_history=True, store_all_simulations=False, save_global_index=False)

    #opt.continuation_max_iter = 20 #< How many iterations per binarization step (default is 20)

 

    ######## RUN THE OPTIMIZER ########

    opt = opt0+opt1+opt2+opt3

    opt.run(working_dir = working_dir)

 

if __name__ == '__main__':

    size_x = 5000 #< Length of the device (in nm). Longer devices typically lead to better performance

    delta_x = 20 #< Size of a pixel along x-axis (in nm)

 

    size_y = 5000 #< Since we use symmetry, this is only have the extent along the y-axis (in nm)

    delta_y = 20 #< Size of a pixel along y-axis (in nm)

 

    filter_R = 100 #< Radius of the smoothing filter which removes small features and sharp corners (in nm)

    

    eps_max = 2.848152**2 #< Effective permittivity for a Silicon waveguide with a thickness of 220nm

    eps_min = 1.44**2 #< Permittivity of the SiO2 cladding

 

    x_points=int(size_x/delta_x)+1

    y_points=int(size_y/delta_y)+1

 

    x_pos = np.linspace(-size_x/2,size_x/2,x_points)*1e-9

    y_pos = np.linspace(-size_y/2,size_y/2,y_points)*1e-9

 

    ## Set initial conditions

    initial_cond = 0.5*np.ones((x_points,y_points))   #< Start with the domain filled with (eps_max+eps_min)/2

 

    ## Alternative initial conditions

    #initial_cond = None                               #< Use the structure 'initial_guess' as defined in the project file

    #initial_cond = np.ones((x_points,y_points))       #< Start with the domain filled with eps_max

    #initial_cond = np.zeros((x_points,y_points))      #< Start with the domain filled with eps_min         

    

    working_dir = os.path.join(cur_path, 'cross_split_x{:04d}_y{:04d}_f{:04d}'.format(size_x,size_y,int(filter_R)))

    runSim(initial_cond, eps_min, eps_max, x_pos, y_pos, filter_R*1e-9, working_dir)

 

[Dev]

Since the Lumerical example running without error, I think the Lumerical API is properly installed. 

1. Try running the script: 

import lumapi

fdtd = lumapi.FDTD()

fdtd.close()

If this fails, ensure:Lumerical API is correctly installed. Python API overview – Ansys Optics

2. Confirm that the 'sim' attribute is properly defined and initialized in your script before it's used within the 'Optimization' object.

3. The function cross_split_base_init_() is defined correctly. The error might be due to the base_script=cross_split_base not being initialized properly. Add a print statement to check: print("Base script content:", cross_split_base)

Thanks