future warning in plotter
/home/jbw/work/code/2014/kwant/kwant/plotter.py:1709: FutureWarning: Using a non-tuple sequence for multidimensional indexing is deprecated; use `arr[tuple(seq)]` instead of `arr[seq]`. In the future this will be interpreted as an array index, `arr[np.array(seq)]`, which will result either in an error or a different result.
field_out[field_slice] += magns