# software

- TREECODE3D_YUKAWA

TREECODE3D_YUKAWA

**is a Fortran90 subroutine for approximating the screened Coulomb (Yukawa) electrostatic energy potential and force of N mutually interacting charged particles in three dimensions using an adaptive treecode.**

Code is available in a zipped tar-file here: TREECODE3D_YUKAWA.tar.gz.

Included in the tar-file is the following README_YUKAWA file.

References:

Code is available in a zipped tar-file here: TREECODE3D_YUKAWA.tar.gz.

Included in the tar-file is the following README_YUKAWA file.

References:

**P. Li, H. Johnston, and R. Krasny, A Cartesian treecode for screened Coulomb interactions, J. Comput. Phys., 228 (2009), 3858-3868.****K. Lindsay, R. Krasny, A particle method and adaptive treecode for vortex sheet motion in 3-D flow, J. Comput. Phys., 172 (2001), 879-907.****Z.-H. Duan, R. Krasny, An adaptive treecode for computing nonbonded potential energy in classical molecular systems, J. Comput. Chem., 22 (2001), 184-195.****K. Lindsay, A three-dimensional Cartesian tree-code and applications to vortex sheet roll-up, Ph.D. Thesis, University of Michigan (1997).**

- DirectSolver2D

DirectSolver2D is a FreeFEM subroutine for simulating the two-dimensional scattering problems of a plane wave by an inhomogeneous medium using the finite element method (FEM).

This program can be used to solve the following two-dimensional scattering problems:

Waves: acoustic waves; elastic waves;

Problem geometry: periodic surfaces; impenetrable obstacles; penetrable media.

The methods are based on:

Methods of domain truncation: perfectly matched layer (PML); Dirichlet-to-Neumann map (DtN);

FEM meshes: uniform meshes; adaptive meshes.

**Code is available in a zipped rar-file here: DirectSolver2D.rar
**Here is the ReadMe file.

References:

- P. Li and X. Yuan, Convergence of an adaptive finite element DtN method for the elastic wave scattering by periodic structures, arXiv:1905.04143.
**P. Li and X. Yuan, Convergence of an adaptive finite element DtN method for the elastic wave scattering proble, arXiv:1903.03606.**- X. Jiang, P. Li, J. Lv, and W. Zheng, An adaptive finite element method for the wave scattering with transparent boundary condition, J. Sci. Comput., 72 (2017), 936-956.
- Z. Wang, G. Bao, J. Li, P. Li, and H. Wu, An adaptive finite element method for the diffraction grating problemwith transparent boundary condition, SIAM J. Numer. Anal., 53 (2015), 1585-1607.