Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ParticLS: Object-oriented software for discrete element methods and
  peridynamics   ParticLS (\emph{Partic}le \emph{L}evel \emph{S}ets) is a software library
that implements the discrete element method (DEM) and meshfree methods.
ParticLS tracks the interaction between individual particles whose geometries
are defined by level sets capable of capturing complex shapes. These particles
either represent rigid bodies or material points within a continuum.
Particle-particle interactions using various contact laws numerically
approximate solutions to energy and mass conservation equations, simulating
rigid body dynamics or deformation/fracture. By leveraging multiple contact
laws, ParticLS can simulate interacting bodies that deform, fracture, and are
composed of many particles. In the continuum setting, we numerically solve the
peridynamic equations -- integro-differential equations capable of modeling
objects with discontinuous displacement fields and complex fracture dynamics.
We show that the discretized peridynamic equations can be solved using the same
software infrastructure that implements the DEM. Therefore, we design a unique
software library where users can easily add particles with arbitrary geometries
and new contact laws that model either rigid-body interaction or peridynamic
constitutive relationships. We demonstrate ParticLS' versatility on test
problems meant to showcase features applicable to a broad selection of fields
such as tectonics, granular media, multiscale simulations, glacier calving, and
sea ice.

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The categories of this paper are: alg-geom
2
The categories of this paper are: math
22
The categories of this paper are: chao-dyn
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The categories of this paper are: funct-an
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The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
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The categories of this paper are: mtrl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: chem-ph
3
The categories of this paper are: physics
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph