don't let divide by zero errors pass by

Author: Shoshana Berleant

nipype/algorithms/confounds.py

@@ -610,6 +610,7 @@ def compute_dvars(in_file, in_mask, remove_zerovariance=False):
  import numpy as np
  import nibabel as nb
  from nitime.algorithms import AR_est_YW
+ import warnings
 
  func = nb.load(in_file).get_data().astype(np.float32)
  mask = nb.load(in_mask).get_data().astype(np.uint8)
@@ -649,9 +650,13 @@ def compute_dvars(in_file, in_mask, remove_zerovariance=False):
  # standardization
  dvars_stdz = dvars_nstd / diff_sd_mean
 
- # voxelwise standardization
- diff_vx_stdz = func_diff / np.array([diff_sdhat] * func_diff.shape[-1]).T
- dvars_vx_stdz = diff_vx_stdz.std(axis=0, ddof=1)
+
+ with warnings.catch_warnings(): # catch divide by zero errors
+ warnings.filterwarnings('error')
+
+ # voxelwise standardization
+ diff_vx_stdz = func_diff / np.array([diff_sdhat] * func_diff.shape[-1]).T
+ dvars_vx_stdz = diff_vx_stdz.std(axis=0, ddof=1)
 
  return (dvars_stdz, dvars_nstd, dvars_vx_stdz)