decimation option for adjoint solver (NanoComp#1722)

* decimation option for adjoint solver

* fixes

* more fixes

* decimation option for EigenmodeCoefficient, FourierFields, Near2FarFields

* add decimation to unit tests in test_adjoint_solver.py

python/adjoint/objective.py

@@ -121,6 +121,7 @@ def __init__(self,
                  mode,
                  forward=True,
                  kpoint_func=None,
+                 decimation_factor=1,
                  **kwargs):
         super().__init__(sim)
         self.volume = volume
@@ -131,13 +132,15 @@ def __init__(self,
         self._monitor = None
         self._normal_direction = None
         self._cscale = None
+        self.decimation_factor = decimation_factor
 
     def register_monitors(self, frequencies):
         self._frequencies = np.asarray(frequencies)
         self._monitor = self.sim.add_mode_monitor(
             frequencies,
             mp.ModeRegion(center=self.volume.center, size=self.volume.size),
             yee_grid=True,
+            decimation_factor=self.decimation_factor,
         )
         self._normal_direction = self._monitor.normal_direction
         return self._monitor
@@ -203,10 +206,11 @@ def __call__(self):
 
 
 class FourierFields(ObjectiveQuantity):
-    def __init__(self, sim, volume, component):
+    def __init__(self, sim, volume, component, decimation_factor=1):
         super().__init__(sim)
         self.volume = volume
         self.component = component
+        self.decimation_factor = decimation_factor
 
     def register_monitors(self, frequencies):
         self._frequencies = np.asarray(frequencies)
@@ -215,6 +219,7 @@ def register_monitors(self, frequencies):
             self._frequencies,
             where=self.volume,
             yee_grid=False,
+            decimation_factor=self.decimation_factor,
         )
         return self._monitor
 
@@ -301,18 +306,20 @@ def __call__(self):
 
 
 class Near2FarFields(ObjectiveQuantity):
-    def __init__(self, sim, Near2FarRegions, far_pts):
+    def __init__(self, sim, Near2FarRegions, far_pts, decimation_factor=1):
         super().__init__(sim)
         self.Near2FarRegions = Near2FarRegions
         self.far_pts = far_pts  #list of far pts
         self._nfar_pts = len(far_pts)
+        self.decimation_factor = decimation_factor
 
     def register_monitors(self, frequencies):
         self._frequencies = np.asarray(frequencies)
         self._monitor = self.sim.add_near2far(
             self._frequencies,
             *self.Near2FarRegions,
             yee_grid=True,
+            decimation_factor=self.decimation_factor,
         )
         return self._monitor
 

python/adjoint/optimization_problem.py

@@ -72,6 +72,7 @@ def __init__(
         decay_dt=50,
         decay_fields=[mp.Ez],
         decay_by=1e-6,
+        decimation_factor=1,
         minimum_run_time=0,
         maximum_run_time=None,
     ):
@@ -128,6 +129,7 @@ def __init__(
         self.decay_by = decay_by
         self.decay_fields = decay_fields
         self.decay_dt = decay_dt
+        self.decimation_factor = decimation_factor
         self.minimum_run_time = minimum_run_time
         self.maximum_run_time = maximum_run_time
 
@@ -215,6 +217,7 @@ def prepare_forward_run(self):
                 self.frequencies,
                 where=dr.volume,
                 yee_grid=True,
+                decimation_factor=self.decimation_factor,
             ) for dr in self.design_regions
         ]
 
@@ -302,6 +305,7 @@ def adjoint_run(self):
                     self.frequencies,
                     where=dr.volume,
                     yee_grid=True,
+                    decimation_factor=self.decimation_factor,
                 ) for dr in self.design_regions
             ]
 

python/tests/test_adjoint_solver.py

@@ -72,21 +72,23 @@ def forward_simulation(design_params,mon_type,frequencies=None, use_complex=Fals
                         sources=sources,
                         geometry=geometry,
                         force_complex_fields=use_complex,
-                        k_point = k)
+                        k_point=k)
     if not frequencies:
         frequencies = [fcen]
 
     if mon_type.name == 'EIGENMODE':
         mode = sim.add_mode_monitor(frequencies,
                                     mp.ModeRegion(center=mp.Vector3(0.5*sxy-dpml-0.1),size=mp.Vector3(0,sxy-2*dpml,0)),
-                                    yee_grid=True)
+                                    yee_grid=True,
+                                    decimation_factor=10)
 
     elif mon_type.name == 'DFT':
         mode = sim.add_dft_fields([mp.Ez],
                                   frequencies,
                                   center=mp.Vector3(1.25),
                                   size=mp.Vector3(0.25,1,0),
-                                  yee_grid=False)
+                                  yee_grid=False,
+                                  decimation_factor=10)
 
     sim.run(until_after_sources=50)
 
@@ -131,14 +133,17 @@ def adjoint_solver(design_params, mon_type, frequencies=None, use_complex=False,
                         sources=sources,
                         geometry=geometry,
                         force_complex_fields=use_complex,
-                        k_point = k)
+                        k_point=k)
+
     if not frequencies:
         frequencies = [fcen]
 
     if mon_type.name == 'EIGENMODE':
         obj_list = [mpa.EigenmodeCoefficient(sim,
                                              mp.Volume(center=mp.Vector3(0.5*sxy-dpml-0.1),
-                                                       size=mp.Vector3(0,sxy-2*dpml,0)),1)]
+                                                       size=mp.Vector3(0,sxy-2*dpml,0)),
+                                             1,
+                                             decimation_factor=5)]
 
         def J(mode_mon):
             return npa.abs(mode_mon)**2
@@ -147,7 +152,8 @@ def J(mode_mon):
         obj_list = [mpa.FourierFields(sim,
                                       mp.Volume(center=mp.Vector3(1.25),
                                                 size=mp.Vector3(0.25,1,0)),
-                                      mp.Ez)]
+                                      mp.Ez,
+                                      decimation_factor=5)]
 
         def J(mode_mon):
             return npa.abs(mode_mon[:,4,10])**2
@@ -158,7 +164,8 @@ def J(mode_mon):
         objective_arguments = obj_list,
         design_regions = [matgrid_region],
         frequencies=frequencies,
-        decay_fields=[mp.Ez])
+        decay_fields=[mp.Ez],
+        decimation_factor=10)
 
     f, dJ_du = opt([design_params])