Utilities

• Utilities are used to manipulate or analyse data, either during runtime or in the post-processing phase.
• Utilities are kept in utils/.
• Avoid editing the contents of the program/ directory; almost all modifications can be made via a utility, rather than altering the core code.
• Some of the utilities are non-specific to pipe flow, e.g. code for the GMRES algorithm.

Building

To build, in Makefile, set UTIL = utilname (omitting the .f90 extension), then type

> make
> make install
> make util
> mv utilname.out ...

The penultimate command creates utilname.out.

Record of parameters

• main.info is created in the install/ directory at compile time by 'make install'. Keep a copy of this file along side your executables.

Pre/post-processing

• ic.f90 - Pre/Post-processing template.
• prim2matlab.f90 - extract data and write in a netcdf format for easy loading into Matlab or VisIt.
• describe_state.f90 - check time/parameters; see also main.info.
• changeMp.f90 - change i_Mp value in a state file.
• change_Mp_alpha.f90 - make copies of a state, e.g. make a state 3x longer using 3 copies of a travelling wave, or insert 2 copies of an m=4 state in an m=2 domain.

Runtime processing

• analyse_runtime.f90 - Runtime processing template.
• newton.f90 - Newton-Krylov for pipe flow.

Non-problem-specific codes

• These are designed for integration with any pre-existing code.
• File:Arnoldi.f - Krylov-subspace method for calculating eigenvalues of a matrix.
• File:GMRESm.f90 - Krylov-subspace method for solving the linear system Ax=b for x.
• File:NewtonHook.f90 - Newton-hookstep method for finding nonlinear solutions x for F(x)=0.