Warn if Source is outside Harminv frequency range

python/simulation.py

@@ -199,9 +199,28 @@ def _collect2(sim):
             return _collect2
         return _collect1
 
+    def _check_freqs(self, sim):
+        source_freqs = [(s.src.frequency, 0 if s.src.width == 0 else 1 / s.src.width)
+                        for s in sim.sources
+                        if hasattr(s.src, 'frequency')]
+
+        harminv_max = self.fcen + 0.5 * self.df
+        harminv_min = self.fcen - 0.5 * self.df
+
+        for sf in source_freqs:
+            sf_max = sf[0] + 0.5 * sf[1]
+            sf_min = sf[0] - 0.5 * sf[1]
+            if harminv_max > sf_max:
+                warn_fmt = "Harminv frequency {} is outside maximum Source frequency {}"
+                warnings.warn(warn_fmt.format(harminv_max, sf_max), RuntimeWarning)
+            if harminv_min < sf_min:
+                warn_fmt = "Harminv frequency {} is outside minimum Source frequency {}"
+                warnings.warn(warn_fmt.format(harminv_min, sf_min), RuntimeWarning)
+
     def _analyze_harminv(self, sim, maxbands):
         harminv_cols = ['frequency', 'imag. freq.', 'Q', '|amp|', 'amplitude', 'error']
         display_run_data(sim, 'harminv', harminv_cols)
+        self._check_freqs(sim)
 
         dt = self.data_dt if self.data_dt is not None else sim.fields.dt
 

python/tests/simulation.py

@@ -2,6 +2,7 @@
 import shutil
 import sys
 import unittest
+import warnings
 import h5py
 import numpy as np
 import meep as mp
@@ -397,6 +398,32 @@ def test_synchronized_magnetic(self):
 
         sim.run(mp.synchronized_magnetic(mp.output_bfield_y), until=10)
 
+    def test_harminv_warnings(self):
+
+        def check_warnings(sim, h, should_warn=True):
+            with warnings.catch_warnings(record=True) as w:
+                warnings.simplefilter("always")
+                sim.run(mp.after_sources(h), until_after_sources=5)
+
+                if should_warn:
+                    self.assertEqual(len(w), 1)
+                    self.assertIn("Harminv", str(w[-1].message))
+                else:
+                    self.assertEqual(len(w), 0)
+
+        sources = [mp.Source(src=mp.GaussianSource(1, fwidth=1), center=mp.Vector3(), component=mp.Ez)]
+        sim = mp.Simulation(cell_size=mp.Vector3(10, 10), resolution=10, sources=sources)
+        h = mp.Harminv(mp.Ez, mp.Vector3(), 1.4, 0.5)
+        check_warnings(sim, h)
+
+        sim = mp.Simulation(cell_size=mp.Vector3(10, 10), resolution=10, sources=sources)
+        h = mp.Harminv(mp.Ez, mp.Vector3(), 0.5, 0.5)
+        check_warnings(sim, h)
+
+        sim = mp.Simulation(cell_size=mp.Vector3(10, 10), resolution=10, sources=sources)
+        h = mp.Harminv(mp.Ez, mp.Vector3(), 1, 1)
+        check_warnings(sim, h, should_warn=False)
+
 
 if __name__ == '__main__':
     unittest.main()