add Chuck's nice downscale2x method

modules/util/util.py

@@ -1294,3 +1294,19 @@ def write_icing_file_nc4_viirs(clvrx_str_time, output_dir, preds_dct, probs_dct,
     proj_ds.setncattr('grid_mapping_name', 'latitude_longitude')
 
     rootgrp.close()
+
+
+def downscale_2x(original, smoothing=False, samples_axis_first=False):
+    # if smoothing:
+    #     original = scipy.ndimage.gaussian_filter(original, sigma = 1/2)
+    if not samples_axis_first:
+        lr = np.nanmean(np.array([original[0::2,0::2],
+              original[1::2,0::2],
+              original[0::2,1::2],
+              original[1::2,1::2]]),axis=0).squeeze()
+    elif samples_axis_first:
+        lr = np.nanmean(np.array([original[:,0::2,0::2],
+              original[:,1::2,0::2],
+              original[:,0::2,1::2],
+              original[:,1::2,1::2]]),axis=0).squeeze()
+    return lr