When using parallel=True, allow for limiting the max number of Worker…

…s used

gdshelpers/export/gdsii_export.py

@@ -84,7 +84,7 @@ def _cell_to_gdsii_binary(cell, grid_steps_per_unit, max_points, max_line_points
 
 
 def write_cell_to_gdsii_file(outfile, cell, unit=1e-6, grid_steps_per_unit=1000, max_points=4000, max_line_points=4000,
-                             timestamp=None, parallel=False):
+                             timestamp=None, parallel=False, max_workers=None):
     name = 'gdshelpers_exported_library'
     grid_step_unit = unit / grid_steps_per_unit
     timestamp = datetime.datetime.now() if timestamp is None else timestamp
@@ -113,7 +113,7 @@ def add_cells_to_unique_list(start_cell):
     # UNITS REAL_8 1/grid_steps_per_unit grid_step_unit
     if parallel:
         from concurrent.futures import ProcessPoolExecutor
-        with ProcessPoolExecutor() as pool:
+        with ProcessPoolExecutor(max_workers=max_workers) as pool:
             num = len(cells)
             for binary in pool.map(_cell_to_gdsii_binary, cells, (grid_steps_per_unit,) * num, (max_points,) * num,
                                    (max_line_points,) * num, (timestamp,) * num):

gdshelpers/geometry/chip.py

@@ -292,7 +292,7 @@ def start_viewer(self):
         import gdspy
         gdspy.LayoutViewer(library=self.get_gdspy_lib(), depth=10)
 
-    def save(self, name=None, library=None, grid_steps_per_micron=1000, parallel=False):
+    def save(self, name=None, library=None, grid_steps_per_micron=1000, parallel=False, max_workers=None):
         """
         Exports the layout and creates an DLW-file, if DLW-features are used.
 
@@ -305,6 +305,8 @@ def save(self, name=None, library=None, grid_steps_per_micron=1000, parallel=Fal
         :param parallel: Defines if parallelization is used (only supported in Python 3).
             Standard value will be changed to True in a future version.
             Deactivating can be useful for debugging reasons.
+        :param max_workers: If parallel is True, this can be used to limit the number of parallel processes.
+            This can be useful if you run into out-of-memory errors otherwise.
         """
 
         if library is not None:
@@ -331,15 +333,16 @@ def save(self, name=None, library=None, grid_steps_per_micron=1000, parallel=Fal
             import shutil
 
             with NamedTemporaryFile('wb', delete=False) as tmp:
-                write_cell_to_gdsii_file(tmp, self, grid_steps_per_unit=grid_steps_per_micron, parallel=parallel)
+                write_cell_to_gdsii_file(tmp, self, grid_steps_per_unit=grid_steps_per_micron, parallel=parallel,
+                                         max_workers=max_workers)
             shutil.move(tmp.name, name + '.gds')
 
         elif library == 'gdspy':
             import gdspy
 
             if parallel:
                 from concurrent.futures import ProcessPoolExecutor
-                with ProcessPoolExecutor() as pool:
+                with ProcessPoolExecutor(max_workers=max_workers) as pool:
                     self.get_gdspy_cell(pool)
             else:
                 self.get_gdspy_cell()
@@ -348,7 +351,7 @@ def save(self, name=None, library=None, grid_steps_per_micron=1000, parallel=Fal
             gdspy_cells = self.get_gdspy_lib().cell_dict.values()
             if parallel:
                 from concurrent.futures import ProcessPoolExecutor
-                with ProcessPoolExecutor() as pool:
+                with ProcessPoolExecutor(max_workers=max_workers) as pool:
                     binary_cells = pool.map(gdspy.Cell.to_gds, gdspy_cells, [grid_steps_per_micron] * len(gdspy_cells))
             else:
                 binary_cells = map(gdspy.Cell.to_gds, gdspy_cells, [grid_steps_per_micron] * len(gdspy_cells))
@@ -360,7 +363,7 @@ def save(self, name=None, library=None, grid_steps_per_micron=1000, parallel=Fal
 
             if parallel:
                 from concurrent.futures import ProcessPoolExecutor
-                with ProcessPoolExecutor() as pool:
+                with ProcessPoolExecutor(max_workers=max_workers) as pool:
                     cells = self.get_oasis_cells(grid_steps_per_micron, pool)
             else:
                 cells = self.get_oasis_cells(grid_steps_per_micron)