Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A modified Ehrenfest formalism for efficient large-scale ab initio
  molecular dynamics
24
The categories of this paper are: dg-ga
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph