Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Cartesian Coordinate, Oblique Boundary, Finite Differences and
  Interpolation   A numerical scheme is described for accurately accommodating oblique,
non-aligned, boundaries, on a three-dimensional cartesian grid. The scheme
gives second-order accuracy in the solution for potential of Poisson's equation
using compact difference stencils involving only nearest neighbors.
Implementation for general "Robin" boundary conditions and for boundaries
between media of different dielectric constant for arbitrary-shaped regions is
described in detail. The scheme also provides for the interpolation of field
(potential gradient) which, despite first-order peak errors immediately
adjacent to the boundaries, has overall second order accuracy, and thus
provides with good accuracy what is required in particle-in-cell codes: the
force. Numerical tests on the implementation confirm the scalings and the
accuracy.

20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph