add psd caching

bilby/gw/detector/interferometer.py

@@ -619,7 +619,10 @@ class Interferometer(object):
         array_like: An array representation of the ASD
 
         """
-        return self.power_spectral_density_array ** 0.5
+        return (
+                self.power_spectral_density.get_amplitude_spectral_density_array(
+                    frequency_array=self.frequency_array) *
+                self.strain_data.window_factor**0.5)
 
     @property
     def power_spectral_density_array(self):
@@ -632,8 +635,10 @@ class Interferometer(object):
         array_like: An array representation of the PSD
 
         """
-        return (self.power_spectral_density.power_spectral_density_interpolated(self.frequency_array) *
-                self.strain_data.window_factor)
+        return (
+            self.power_spectral_density.get_power_spectral_density_array(
+                frequency_array=self.frequency_array) *
+            self.strain_data.window_factor)
 
     @property
     def frequency_array(self):

bilby/gw/detector/psd.py

@@ -47,6 +47,15 @@ class PowerSpectralDensity(object):
             self.asd_array = asd_array
         self.psd_file = psd_file
         self.asd_file = asd_file
+        self._cache = dict(
+            frequency_array=np.array([]), psd_array=None, asd_array=None)
+        self._update_cache(self.frequency_array)
+
+    def _update_cache(self, frequency_array):
+        psd_array = self.power_spectral_density_interpolated(frequency_array)
+        self._cache['psd_array'] = psd_array
+        self._cache['asd_array'] = psd_array**0.5
+        self._cache['frequency_array'] = frequency_array
 
     def __eq__(self, other):
         if self.psd_file == other.psd_file \
@@ -183,6 +192,16 @@ class PowerSpectralDensity(object):
                                                               bounds_error=False,
                                                               fill_value=np.inf)
 
+    def get_power_spectral_density_array(self, frequency_array):
+        if not np.array_equal(frequency_array, self._cache['frequency_array']):
+            self._update_cache(frequency_array=frequency_array)
+        return self._cache['psd_array']
+
+    def get_amplitude_spectral_density_array(self, frequency_array):
+        if not np.array_equal(frequency_array, self._cache['frequency_array']):
+            self._update_cache(frequency_array=frequency_array)
+        return self._cache['asd_array']
+
     @property
     def power_spectral_density_interpolated(self):
         return self.__power_spectral_density_interpolated