PYRAMID is a software library used for the automatic adaptive refinement of large unstructured meshes on parallel computers and clusters. This software library can be easily used in a variety of unstructured parallel computational applications, including parallel finite element, parallel finite volume, parallel visualization applications using triangular or tetrahedral meshes, and quality controlled parallel mesh generation from initial coarse element models. The library contains a suite of well designed, and efficiently implemented, modules that perform operations in a typical parallel AMR process. Among these are:

• Mesh quality control during successive parallel adaptive refinement (typically guided by a local-error estimator).
  
  
• Parallel adaptive refinement.
  
  
• Parallel mesh migration and load balancing.
  
  
• Parallel mesh partitioning using ParMetis.
  
  
• Visualization (Tecplot format).
  
  

The Pyramid library is implemented in Fortran 90/95 with the Message-Passing Interface (MPI) and parallel partitioning library (ParMetis) supporting code efficiency, modularity, and portability. It is scalable to hundreds of processors and millions of elements. Visualization is supported using Tecplot.

Examples:
Click on each image to see full-scale.

Tetrahedral artery mesh (geometry from C. A. Taylor) where color shows processor assignments.

Tetrahedral earthquake fault mesh where color shows processor assignments.

Tetrahedral cylinder region mesh where color shows processor assignments.

Triangular mesh showing field from modeling of the magnetopause.