fix wavex_setup and dmwavex_setup

src/pint/utils.py

@@ -1328,8 +1328,9 @@ def wavex_setup(model, T_span, freqs=None, n_freqs=None):
             "Both freqs and n_freqs are specified. Only one or the other should be used"
         )
 
-    if n_freqs <= 0:
+    if n_freqs is not None and n_freqs <= 0:
         raise ValueError("Must use a non-zero number of wave frequencies")
+
     model.add_component(WaveX())
     if isinstance(T_span, u.quantity.Quantity):
         T_span.to(u.d)
@@ -1356,11 +1357,11 @@ def wavex_setup(model, T_span, freqs=None, n_freqs=None):
 
     if n_freqs is not None:
         if n_freqs == 1:
-            wave_freq = 2.0 * np.pi / T_span
+            wave_freq = 1 / T_span
             model.WXFREQ_0001.quantity = wave_freq
         else:
             wave_numbers = np.arange(1, n_freqs + 1)
-            wave_freqs = 2.0 * np.pi * wave_numbers / T_span
+            wave_freqs = wave_numbers / T_span
             model.WXFREQ_0001.quantity = wave_freqs[0]
             model.components["WaveX"].add_wavex_components(wave_freqs[1:])
     return model.components["WaveX"].get_indices()
@@ -1408,8 +1409,9 @@ def dmwavex_setup(model, T_span, freqs=None, n_freqs=None):
             "Both freqs and n_freqs are specified. Only one or the other should be used"
         )
 
-    if n_freqs <= 0:
+    if n_freqs is not None and n_freqs <= 0:
         raise ValueError("Must use a non-zero number of wave frequencies")
+
     model.add_component(DMWaveX())
     if isinstance(T_span, u.quantity.Quantity):
         T_span.to(u.d)
@@ -1436,11 +1438,11 @@ def dmwavex_setup(model, T_span, freqs=None, n_freqs=None):
 
     if n_freqs is not None:
         if n_freqs == 1:
-            wave_freq = 2.0 * np.pi / T_span
+            wave_freq = 1 / T_span
             model.DMWXFREQ_0001.quantity = wave_freq
         else:
             wave_numbers = np.arange(1, n_freqs + 1)
-            wave_freqs = 2.0 * np.pi * wave_numbers / T_span
+            wave_freqs = wave_numbers / T_span
             model.DMWXFREQ_0001.quantity = wave_freqs[0]
             model.components["DMWaveX"].add_dmwavex_components(wave_freqs[1:])
     return model.components["DMWaveX"].get_indices()