Configuring Trilinos for an external build of Sundance

Here we explain how to configure Trilinos for Sundance. The hard part is knowing the appropriate arguments for configure. If you are running on Linux, the easiest solution is to copy one of my Canned Scripts that call configure.

Do I need PyTrilinos?

PyTrilinos is not required by PySundance. There is probably no harm in building PyTrilinos, but it is not used by PySundance.

Optimized vs Debug Configurations

Most compilers let you control the level of compile-time optimization used and whether to produce annotations required by debuggers. Other compilation options you might want to set control the level of warning and diagnostic output to be produced during compile time. Such options can be passed to the compiler by using the CXXFLAGS argument to configure.

One optional Trilinos configuration flag significantly impacts the behavior of Sundance:

--enable-teuchos-abc turns on array bounds checking in Teuchos, which will check every access to Teuchos Array objects for bounds errors. This is nice for debugging, but results in a serious slowdown of the resulting code and so should probably be disabled in production builds.

Typically, I find that Sundance simulators compiled with optimization are about 3-5 times faster in matrix assembly than those compiled with debugging and array bounds checking.

It is possible to turn on debugging and optimization simultaneously, but (a) compilation will be very slow and very memory-intensive, and (b) the resulting debugging information might be useless because optimizations can change sometimes the effective ordering of source lines.

Canned Scripts

In the directory Sundance/trilinos-scripts there are several scripts for configuring Trilinos for Sundance on Linux using the Gnu compilers. You should be able to use these as a starting point for configuring on other platforms.

Trilinos packages to enable

If you are writing your own configuration script for Trilinos, you should always enable the following packages:

Teuchos (utilities)

--enable-teuchos 
--enable-teuchos-extended 
--enable-teuchos-complex 
--enable-teuchos-expat

Thyra (abstract interfaces for linear algebra)

--enable-thyra
--enable-epetra-thyra
--enable-amesos-thyra
--enable-ifpack-thyra
--enable-aztecoo-thyra
--enable-ml-thyra

Epetra (core distributed sparse linear algebra objects)
```
--enable-epetra
```
Epetraext (various sparse matrix utilities)
```
--enable-epetraext
```
IFPack (incomplete factorization preconditioners)
```
--enable-ifpack
```
ML (algebraic multilevel preconditioners)
```
--enable-ml
```
AztecOO (iterative solvers)
```
--enable-aztecoo
```
NOX (nonlinear solvers)
```
--enable-nox
```

Amesos (direct solvers)

--enable-amesos 
--enable-amesos-umfpack