Some Python 3 compatibility fixes (#2508)

* gaussian.py: minor division fix for Python 3 compatability

* utils.py: move division fixes for Python 3 compatibility

pycbc/noise/gaussian.py

@@ -102,8 +102,8 @@ def noise_from_psd(length, delta_t, psd, seed=None):
     randomness = lal.gsl_rng("ranlux", seed)
 
     N = int (1.0 / delta_t / psd.delta_f)
-    n = N/2+1
-    stride = N/2
+    n = N//2+1
+    stride = N//2
 
     if n > len(psd):
         raise ValueError("PSD not compatible with requested delta_t")

pycbc/waveform/utils.py

@@ -436,13 +436,13 @@ def td_taper(out, start, end, beta=8, side='left'):
     winlen = 2 * int(width / out.delta_t)
     window = Array(signal.get_window(('kaiser', beta), winlen))
     xmin = int((start - out.start_time) / out.delta_t)
-    xmax = xmin + winlen/2
+    xmax = xmin + winlen//2
     if side == 'left':
-        out[xmin:xmax] *= window[:winlen/2]
+        out[xmin:xmax] *= window[:winlen//2]
         if xmin > 0:
             out[:xmin].clear()
     elif side == 'right':
-        out[xmin:xmax] *= window[winlen/2:]
+        out[xmin:xmax] *= window[winlen//2:]
         if xmax < len(out):
             out[xmax:].clear()
     else:
@@ -480,12 +480,12 @@ def fd_taper(out, start, end, beta=8, side='left'):
     winlen = 2 * int(width / out.delta_f)
     window = Array(signal.get_window(('kaiser', beta), winlen))
     kmin = int(start / out.delta_f)
-    kmax = kmin + winlen/2
+    kmax = kmin + winlen//2
     if side == 'left':
-        out[kmin:kmax] *= window[:winlen/2]
+        out[kmin:kmax] *= window[:winlen//2]
         out[:kmin] *= 0.
     elif side == 'right':
-        out[kmin:kmax] *= window[winlen/2:]
+        out[kmin:kmax] *= window[winlen//2:]
         out[kmax:] *= 0.
     else:
         raise ValueError("unrecognized side argument {}".format(side))