1) In mdgxs.py, DecayRate, get_xs(). There is no need to reverse the order
since there isn't an energy group filter anymore. Also, the new_shape
addition formats the cross section like all the others. I updated
mgxs_library_hdf5 test results accordingly.
2) In material.cpp. If you use a macroscopic dnesity other than 1.0,
the code still pushed back '1.0'. My change fixes that. Using a macro
density other than 1.0 wasn't tested anywhere, so I modifed mg_convert
to take a density of 1.1. The default macro density of 1.0 is used in
many other tests.
3) tally_scoring.cpp. Notice that the score is accumulated, then sent
to the function score_fission_delayed_dg where the tally is accumulated.
This amounts to "double accumulation". It makes sense to accumulate the score
over the delayed groups if there is no delayed group filter, but in this
case, when delayed group filter is not None, the score needs to reset
each time.
In other parts of SCORE_DECAY_RATE, I think the distinction between
accumulating and resetting the score is correct. The only place I wasn't
sure was line 1057 (and its equivalent in multi-group, line 1962).
It's too bad the decay-rate isn't tested very thoroughly. Although I
don't have time to do it myself, I think adding a DelayedGroups filter
to the mg_tallies test would be a good start.
