Fixing bug in dt

bilby/gw/detector/interferometer.py

@@ -298,7 +298,11 @@ class Interferometer(object):
 
         time_shift = self.time_delay_from_geocenter(
             parameters['ra'], parameters['dec'], parameters['geocent_time'])
-        dt = parameters['geocent_time'] + time_shift - self.strain_data.start_time
+
+        # Be careful to first substract the two GPS times which are ~1e9 sec.
+        # And then add the time_shift which varies at ~1e-5 sec
+        dt_geocent = parameters['geocent_time'] - self.strain_data.start_time
+        dt = dt_geocent + time_shift
 
         signal_ifo[self.strain_data.frequency_mask] = signal_ifo[self.strain_data.frequency_mask] * np.exp(
             -1j * 2 * np.pi * dt * self.strain_data.frequency_array[self.strain_data.frequency_mask])

bilby/gw/likelihood.py

@@ -895,8 +895,8 @@ class ROQGravitationalWaveTransient(GravitationalWaveTransient):
         dt = interferometer.time_delay_from_geocenter(
             self.parameters['ra'], self.parameters['dec'],
             self.parameters['geocent_time'])
-        ifo_time = self.parameters['geocent_time'] + dt - \
-            interferometer.strain_data.start_time
+        dt_geocent = self.parameters['geocent_time'] - interferometer.strain_data.start_time
+        ifo_time = dt_geocent + dt
 
         calib_linear = interferometer.calibration_model.get_calibration_factor(
             self.frequency_nodes_linear,