added a docstring

Author: JensNRAD

nipype/interfaces/fsl/dti.py

@@ -482,6 +482,23 @@ class ProbTrackX2OutputSpec(ProbTrackXOutputSpec):
 
 
 class ProbTrackX2(ProbTrackX):
+    """ Use FSL  probtrackx2 for tractography on bedpostx results
+
+    Examples
+    --------
+
+    >>> from nipype.interfaces import fsl
+    >>> pbx2 = fsl.ProbTrackX2 seed='data.bedpostX/seed_source.nii.gz', \
+    thsamples=['data.bedpostX/merged_th1samples.nii.gz'], \
+    fsamples=['data.bedpostX/merged_f1samples.nii.gz'], \ 
+    phsamples=['data.bedpostX/merged_ph1samples.nii.gz'], \ 
+    mask='data.bedpostX/nodif_brain_mask.nii.gz', \
+    out_dir='.',
+    n_samples=3, \
+    n_steps=10)
+    >>> pbx2.cmdline
+    'probtrackx2 --forcedir -m data.bedpostX/nodif_brain_mask.nii.gz --nsamples=3 --nsteps=10 --opd --dir=. --samples=merged --seed=data.bedpostX/seed_source.nii.gz'
+    """
     _cmd = 'probtrackx2'
     input_spec = ProbTrackX2InputSpec
     output_spec = ProbTrackX2OutputSpec