[yt-dev] Issue #1189: error in volume rendering if north_vector is aligned with normal_vector (yt_analysis/yt)

Michael Zingale issues-reply at bitbucket.org
Sun Mar 20 17:09:18 PDT 2016


New issue 1189: error in volume rendering if north_vector is aligned with normal_vector
https://bitbucket.org/yt_analysis/yt/issues/1189/error-in-volume-rendering-if-north_vector

Michael  Zingale:

If the normal_vector is aligned with the north_vector, the volume rendering fails:

```
  File "/home/zingale/development/yt-mz/yt/visualization/volume_rendering/camera.py", line 320, in switch_orientation
    self._setup_normalized_vectors(normal_vector, north_vector)
  File "/home/zingale/development/yt-mz/yt/utilities/orientation.py", line 92, in _setup_normalized_vectors
    self.inv_mat = np.linalg.pinv(self.unit_vectors)
  File "/usr/lib64/python2.7/site-packages/numpy/linalg/linalg.py", line 1585, in pinv
    u, s, vt = svd(a, 0)
  File "/usr/lib64/python2.7/site-packages/numpy/linalg/linalg.py", line 1327, in svd
    u, s, vt = gufunc(a, signature=signature, extobj=extobj)
  File "/usr/lib64/python2.7/site-packages/numpy/linalg/linalg.py", line 99, in _raise_linalgerror_svd_nonconvergence
    raise LinAlgError("SVD did not converge")
numpy.linalg.linalg.LinAlgError: SVD did not converge
```

If I offset it even just a little bit, then it works.  But if I want to do a rendering looking down at "north", we get this message.  If this is a limitation of the VR, we should do a check and issue a warning.





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