no more need to flip visibilities on the user side

demo_wstack_realdata.py

@@ -65,11 +65,6 @@ wgt = np.repeat(wgt[:, None], len(freq), axis=1)
 # FLAGGED -> WGT=0
 wgt[flags] = 0
 
-# flip visibilities with w<0
-mask = uvw[:, 2] < 0
-uvw[mask] *= -1
-vis = np.conj(vis)*mask.reshape(-1, 1) + vis*(1-mask.reshape(-1, 1))
-
 npixdirty = 756
 DEG2RAD = np.pi/180
 pixsize = 2.3/npixdirty*DEG2RAD