# Documentation

## Overture mailing list.

You can join the**Overture mailing list**by going to http://www.freelists.org/list/overture. Then post mail to

*overture@freelists.org*. Use this forum to ask questions about Overture.

The searchable list archive of previous posts to the overture mailing list is found at http://www.freelists.org/archives/overture (you don't need to join the mailing list to view the archive).

The

*old*Overture mailing list (until September 2007) was at http://www.topica.com/lists/overture. You can go here if you want to see old posts and old questions/answers.

## Overture demo and short course.

Here are some demo and short course documents for Overture.- "Overture Demo Introduction", K. Chand and W. Henshaw
- "Hands-on Demo of Overture and the CG Solvers", K. Chand and W. Henshaw
- "Short Course: Solving PDE's on Overlapping Grids with the Overture Framework", W. Henshaw

## Source code documentation.

- "Overture source code documentation" in Doxygen format.

- "CG source code documentation" in Doxygen format.

## Overture documentation.

### The Overture Graphics Interface.

If you run Overture or CG solvers you will want to learn about the interactive graphics interface and the graphics post-processor*plotStuff*.

- "The Overture Graphics Interface", by W. Henshaw and A. Petersson describes the Overture graphics interface (e.g. mouse-buttons, command window, saving hard copies, making movies) and associated classes (PlotIt, GL_GraphicsInterface, GraphicsParameters) and also how to plot grids and grid functions (contours, streamlines) etc. from within you Overture code.
- "The plotStuff graphics post-processor", by W. Henshaw
describes how to plot results from Overture programs that have been saved in
*show files*. It also discusses how to create user defined*derived types*for plotting.

### Grid Generation.

If you are using Overture to generate grids for use with the CG solvers or your own solver then here are documents that describe grid generation.- "Ogen: an overlapping grid generator", by W. Henshaw. Ogen is the program that is used to generate an overlapping grid (i.e. hole-cutting and computing interpolation points) from a collection of overlapping component grids.
- "Mappings for Overture", by W. Henshaw. This document describes the Mapping classes that are used to define geometry such as spheres, cylinders, splines, NURBS, bodies of revolution, elliptic and hyperbolic grid generation etc. These Mappings are turned into component grids.
- "Hyperbolic Grid Generator", W. Henshaw. The hyperbolic grid generator is a power tool for building grids by marching off curves and surfaces.
- "Ugen hybrid grid generator", by K. Chand, describes the Ugen unstructured grid generator that can be used to build hybrid grids (part structured and part unstructured). Note that most Overture codes do not work with hybrid grids but some of the operators do.
- "Smesh grid generator", by K. Chand, describes the smesh mesh generator, that can be used to simply generate 2D unstructured meshes.
- "An Overture Tool for CAD Cleanup and Modification", by W.D. Henshaw, K. Chand, and N.A. Petersson describes the class that can be used to build geometry, read edit, and repair CAD geometry, and build meshes on CAD geometry and triangluated surfaces.

### Writing Overture programs.

If you are writing programs in Overture here are documents that describe capabilities of the important classes.- "A Primer for Overture", by W. Henshaw. This document presents
a series of C++ programs that use the classes in Overture to solve PDEs.
**This is a good place to start if you want to write programs with Overture.**. - "Overture Operators and Boundary Conditions", by W. Henshaw. This document describes the conservative and non-conservative difference approximations to differential operators and a large collection of elementary boundary conditions.
- "Other Stuff", by W. Henshaw. This document describes various
supporting classes. These include the OgFunction classes for
*twilight-zone solutions*(i.e. manufactured solutions), the DataBase classes for saving data to HDF files, the Integrate class for integrating functions on overlapping grids, and the Tridiangonal classes for solving systems of tridiagonal and pentadiagonal equations. - "Overture Sparse Equation Solver", by P. Fast and W. Henshaw. This class acts as an interface from Overture coefficient matrices to various solvers for sparse matrices (e.g. PETSc).
- "Ogshow and ShowFileReader", by W. Henshaw describes the Ogshow and
ShowFileReader classes that can
be used to save and read solutions to a
*show files*from an Overture program. - "Time Step Determination for PDEs with Applications to Programs Written with Overture", by W. Henshaw, shows one how to compute the time step for a PDE discretized on a curvilinear grid with Overture operators.

### A++/P++ documentation (Serial/Parallel C++ Array Class).

A++/P++ serial/parallel arrays are used throughout Overture. These are multidimensional arrays that can be used in C++. These array classes have not changed very much in the past years and so the documentation is old but still mainly valid.- " A++/P++ Quick Reference Manual", tells you almost everything you need know to get started.
- "A++/P++ Manual", provides more details.
- "A++/P++ Tutorial Guide".
- "A++/P++ Reference Examples".

### Overture classes for the expert.

Here are documents that go into more detail about various Overture classes.- "Overture Grid Classes User Guide", by G. Chesshire and W. Henshaw, describe the MappedGrid, GridCollection and CompositeGrid classes.
- "Overture Grid Classes Reference Manual", by G. Chesshire and W. Henshaw, is the reference manual for the MappedGrid, GridCollection and CompositeGrid classes.
- "Overture Grid Functions", by W. Henshaw, describes the grid function classes (realMappedGridFunction, realGridCollectionFunction, realCompositeGridFunction) that are used to hold solutions (fields) such as density, velocity, pressure etc.
- "Adaptive Mesh Refinement Routines for Overture", by D. Brown and W. Henshaw describes the AMR classes in Overture.
- "Overture Data Base Classes", by W. Henshaw describes the DataBase class that acts an interface to scientific data-bases and an implementation based on HDF.
- "User Guide for Ogmg", by W. Henshaw is the user guide for the overlapping grid multigrid solver.
- "Overture Developers Guide", by W. Henshaw gives some useful info for those writing software with Overture. This is mainly intended for developers on the Overture team.

## CG documentation (Composite Grid PDE Solvers).

Here are documents that describe the different CG PDE solvers. The documentation for Cgsm, Cgcns, and Cgmp is still under development.- "Cgins User Guide", user guide for the Cgins incompressible flow solver.
- "Cgins Reference Manual", reference manual for the Cgins incompressible flow solver. This manual has a section with a large collection of sample simulations that show the capabilties of Cgins.
- "Cgmx Users Guide", user guide for the Cgmx electromagnetics solver.
- "Cgcns (OverBlown) Users Guide". The Cgcns user guide is still under development. For now use the older OverBlown user guide.
- "Cgcns (OverBlown) Reference Manual". The Cgcns reference manual guide is still under development. For now use the older OverBlown reference manual.
- "Cgad Users Guide", for the advection diffusion solver with possibly moving and deforming interfaces.
- "Moving Bodies with Overture and the CG Solvers", a description of how moving bodies can be used with the CG solvers.