Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Efficient Monte Carlo Algorithm for a Restricted Class of Scattering
  Problems in Radiation Transfer   We describe an efficient Monte Carlo algorithm for a restricted class of
scattering problems in radiation transfer. This class includes many
astrophysically interesting problems, including the scattering of ultraviolet
and visible light by grains. The algorithm correctly accounts for
multiply-scattered light. We describe the algorithm, present a number of
important optimizations, and explicity show how the algorithm can be used to
estimate quantities such as the emergent and mean intensity. We present two
test cases, examine the importance of the optimizations, and show that this
algorithm can be usefully applied to optically-thin problems, a regime
sometimes considered limited to explicit single-scattering plus attenuation
approximations.

5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
14
The categories of this paper are: math-ph
2
The categories of this paper are: math
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg