Diag.fractional_distance_photon_may_travel
==========================================
The distance photon may travel in a cell is limited to prevent a photon
from moving such a long path that the velocity may change non-linearly.
This problem arises primarily when the photon is travelling azimuthally
in the grid.  This changes the default for the fraction of the maximum
distance in a cell.

Type
  Double

Values
  0 to 1

File
  `diag.c <https://github.com/sirocco-rt/sirocco/blob/master/source/diag.c>`_


Parent(s)
  * :ref:`Diag.use_standard_care_factors`: ``False``