refraction bug

[astraw]

I just hit this:

Exception in thread CoordinateProcessor:
Traceback (most recent call last):
File "/usr/lib/python2.7/threading.py", line 551, in __bootstrap_inner
self.run()
File "/usr/lib/python2.7/dist-packages/flydra/main_brain/coordinate_receiver.py", line 418, in run
self.process_data( incoming_2d_data )
File "/usr/lib/python2.7/dist-packages/flydra/main_brain/coordinate_receiver.py", line 555, in process_data
deferred_2d_data,
File "/usr/lib/python2.7/dist-packages/flydra/main_brain/coordinate_receiver.py", line 706, in _process_parsed_data
debug2=self.debug_level.isSet())
File "/usr/lib/python2.7/dist-packages/flydra/kalman/flydra_tracker.py", line 117, in calculate_a_posteriori_estimates
debug1=debug2) for tro in self.live_tracked_objects ]
File "_flydra_tracked_object.pyx", line 365, in _flydra_tracked_object.TrackedObject.calculate_a_posteriori_estimate (src/_flydra_tracked_object.c:5965)
File "_flydra_tracked_object.pyx", line 472, in _flydra_tracked_object.TrackedObject._filter_data (src/_flydra_tracked_object.c:10111)
File "_flydra_tracked_object.pyx", line 515, in _flydra_tracked_object.TrackedObject._filter_data (src/_flydra_tracked_object.c:8011)
File "/usr/lib/python2.7/dist-packages/flydra/reconstruct.py", line 1646, in find2d
distorted=distorted )
File "/usr/lib/python2.7/dist-packages/flydra/water.py", line 48, in view_points_in_water
height, r[i], depth[i]))
File "_refraction.pyx", line 41, in _refraction.find_fastest_path_fermat (src/_refraction.c:746)
File "_refraction.pyx", line 63, in _refraction.find_fastest_path_fermat (src/_refraction.c:618)
File "_Roots3And4.pyx", line 24, in _Roots3And4.real_root_less_than (src/_Roots3And4.c:651)
ValueError: more than one valid root found