Run shape optimization using a cross as a starting guess. Args: resolution: Simulation resolution in pixels/micron. beta: Tanh function projection strength parameter, ranging from [0,∞]. maxeval: Maximum number of optimization iterations to run. use_smoothed_proj
(
resolution: float,
beta: float,
maxeval: int,
use_smoothed_projection: bool = True,
damping_factor: float = 0.0,
dx: float = DEFAULT_DESIGN_REGION_WIDTH,
dy: float = DEFAULT_DESIGN_REGION_HEIGHT,
waveguide_width: float = DEFAULT_WAVEGUIDE_WIDTH,
output_filename_prefix: Optional[str] = None,
plot_results: bool = True,
)
| 278 | |
| 279 | |
| 280 | def run_shape_optimization( |
| 281 | resolution: float, |
| 282 | beta: float, |
| 283 | maxeval: int, |
| 284 | use_smoothed_projection: bool = True, |
| 285 | damping_factor: float = 0.0, |
| 286 | dx: float = DEFAULT_DESIGN_REGION_WIDTH, |
| 287 | dy: float = DEFAULT_DESIGN_REGION_HEIGHT, |
| 288 | waveguide_width: float = DEFAULT_WAVEGUIDE_WIDTH, |
| 289 | output_filename_prefix: Optional[str] = None, |
| 290 | plot_results: bool = True, |
| 291 | ): |
| 292 | """Run shape optimization using a cross as a starting guess. |
| 293 | |
| 294 | Args: |
| 295 | resolution: Simulation resolution in pixels/micron. |
| 296 | beta: Tanh function projection strength parameter, ranging from [0,∞]. |
| 297 | maxeval: Maximum number of optimization iterations to run. |
| 298 | use_smoothed_projection: Whether or not to use the smoothed projection. |
| 299 | dx: Design region width in microns. |
| 300 | dy: Design region height in microns. |
| 301 | waveguide_width: Waveguide width in microns. |
| 302 | output_filename_prefix: The filename prefix that will store the |
| 303 | optimization results. If `None`, no file is saved. |
| 304 | plot_results: Whether or not to plot results. |
| 305 | |
| 306 | Returns: |
| 307 | The design and FOM result arrays, along with the optimization problem |
| 308 | and mapping function. |
| 309 | |
| 310 | """ |
| 311 | # Initialize the optimization problem and mapping functions |
| 312 | opt, mapping = build_optimization_problem( |
| 313 | resolution=resolution, |
| 314 | beta=beta, |
| 315 | dx=dx, |
| 316 | dy=dy, |
| 317 | waveguide_width=waveguide_width, |
| 318 | use_smoothed_projection=use_smoothed_projection, |
| 319 | damping_factor=damping_factor, |
| 320 | ) |
| 321 | |
| 322 | # pull number of parameters from the design region |
| 323 | n = opt.design_regions[0].design_parameters.weights.size |
| 324 | grid_size = opt.design_regions[0].design_parameters.grid_size |
| 325 | Nx, Ny = int(grid_size.x), int(grid_size.y) |
| 326 | |
| 327 | # Set up the optimizer |
| 328 | algorithm = nlopt.LD_CCSAQ |
| 329 | solver = nlopt.opt(algorithm, n) |
| 330 | solver.set_lower_bounds(0) |
| 331 | solver.set_upper_bounds(1) |
| 332 | solver.set_maxeval(maxeval) |
| 333 | |
| 334 | # initial guess, which is just a simple waveguide crossing |
| 335 | x = np.linspace(-dx / 2, dy / 2, Nx) |
| 336 | y = np.linspace(-dx / 2, dy / 2, Ny) |
| 337 | X, Y = np.meshgrid(x, y) |
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