From 1614959d18003ca3a8088cca188ef61da725a6e7 Mon Sep 17 00:00:00 2001
From: Ardavan Oskooi <oskooi@users.noreply.github.com>
Date: Thu, 26 Mar 2020 18:52:19 -0700
Subject: [PATCH] get_ldos_freqs method for Python LDOS objects (#1156)

---
 doc/docs/Python_User_Interface.md | 4 ++--
 python/meep.i                     | 1 +
 python/simulation.py              | 6 +++++-
 python/tests/ldos.py              | 3 +--
 4 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/doc/docs/Python_User_Interface.md b/doc/docs/Python_User_Interface.md
index d69bda767..cdbdf1ea7 100644
--- a/doc/docs/Python_User_Interface.md
+++ b/doc/docs/Python_User_Interface.md
@@ -1417,9 +1417,9 @@ Meep can also calculate the LDOS (local density of states) spectrum, as describe
 —
 Create an LDOS object with frequency bandwidth `df` centered at `fcen`, at `nfreq` frequency points. This can be passed to the `dft_ldos` step function below, and has the properties `freq_min`, `nfreq` and `dfreq`.
 
-**`freqs()`**
+**`get_ldos_freqs(ldos)`**
 —
-Method of `Ldos` that returns a list of the frequencies that this `Ldos` instance is computing the spectrum for.
+Given an LDOS object, returns a list of the frequencies that it is computing the spectrum for.
 
 **`dft_ldos(fcen=None, df=None, nfreq=None, ldos=None)`**
 —
diff --git a/python/meep.i b/python/meep.i
index f4180caf8..819a91a6d 100644
--- a/python/meep.i
+++ b/python/meep.i
@@ -1454,6 +1454,7 @@ PyObject *_get_array_slice_dimensions(meep::fields *f, const meep::volume &where
         get_fluxes,
         get_force_freqs,
         get_forces,
+        get_ldos_freqs,
         get_magnetic_energy,
         get_near2far_freqs,
         get_total_energy,
diff --git a/python/simulation.py b/python/simulation.py
index 46ad912a1..3a9476d48 100644
--- a/python/simulation.py
+++ b/python/simulation.py
@@ -2961,7 +2961,7 @@ def _ldos(sim, todo):
             sim.ldos_data = mp._dft_ldos_ldos(ldos)
             sim.ldos_Fdata = mp._dft_ldos_F(ldos)
             sim.ldos_Jdata = mp._dft_ldos_J(ldos)
-            display_csv(sim, 'ldos', zip(ldos.freq, sim.ldos_data))
+            display_csv(sim, 'ldos', zip(mp.get_ldos_freqs(ldos), sim.ldos_data))
     return _ldos
 
 
@@ -2969,6 +2969,10 @@ def scale_flux_fields(s, flux):
     flux.scale_dfts(s)
 
 
+def get_ldos_freqs(l):
+    return [l.freq[i] for i in range(l.freq.size())]
+
+
 def get_flux_freqs(f):
     return [f.freq[i] for i in range(f.freq.size())]
 
diff --git a/python/tests/ldos.py b/python/tests/ldos.py
index 481a7fcb5..f61684d0b 100644
--- a/python/tests/ldos.py
+++ b/python/tests/ldos.py
@@ -1,4 +1,3 @@
-import math
 import unittest
 
 import meep as mp
@@ -43,7 +42,7 @@ def test_ldos_user_object(self):
         )
 
         self.assertAlmostEqual(self.sim.ldos_data[0], 1.011459560620368)
-        self.assertEqual(ldos.freq.size(), 1)
+        self.assertEqual(len(mp.get_ldos_freqs(ldos)), 1)
 
     def test_invalid_dft_ldos(self):
         with self.assertRaises(ValueError):