ARANEA, a program for generating unstructured triangular meshes with a JAVA Graphics User Interface. R. Marchand, M. Charbonneau-Lefort, M. Dumberry, B. Pronovost.

PROGRAM SUMMARY
Title of program: Aranea
Catalogue identifier: ADOG
Ref. in CPC: 139(2001)172
Distribution format: gzip file
Operating system: Windows 95/98/2000/NT, Tru64 V4.0f, SGI Irix
High speed store required: 6.5MK words
Number of lines in distributed program, including test data, etc: 168822
Keywords: General purpose, Utility, Unstructured mesh generation, Triangular mesh, User Interface Graphics.
Programming language used: Java
Computer: PC , Alpha workstation , SGI Origin 2000 , Solaris 7 SPARC , Solaris 8x86 , PowerMac G4/350 MHz , iMac G3/400 MHz .

Nature of problem:
Several physical problems can be described in terms of coupled partial equations in two dimensions. This is the case, for example, with plasma particle and energy transport in axisymmetric tokamaks, or with the evolution of vorticity in non neutral electron cylinders. At the basis of solution of such equations is a discretisation of the governing equations on a given mesh. Aranea is a code that automatically generates unstructured triangular meshes in two dimensional plane geometry, with arbitrary boundary shapes and connectivity. The resulting meshes are well suited for solutions with the finite element discretization.

Method of solution:
The construction of a mesh in Aranea is made according to a parametrization of boundaries, a definition of boundary properties, and a definition of the metric. The parametrization of the boundaries defines the shape and connectivity of the various boundaries that determine the simulation domain. Boundary properties refer to the ability of various boundaries to specify boundary conditions or not. They also refer to the fact that some boundaries are used to delimit the simulation domain, while other boundaries may be used for the sole purpose of aligning the mesh in certain regions of the simulation domain. Finally, the metric specifies the desired size of the elements that will make the mesh. The grid is then constructed by adding mesh points at desired locations and defining the connectivity with neighbouring points with the Bowyer-Watson algorithm.

Restrictions:
The meshes generated by Aranea must be in plane geometry.

Typical running time:
The running time may vary considerably, depending on the problem being considered. The test cases presented were run on a 450 MHz pentium II processor with 128 MB of RAM, under Windows 98. The execution time varied from one to four seconds.

Unusual features:
None.