Utilities

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

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.

It is good practice to do a 'make install' to generate a main.info file to keep alongside the executable.

main.info - Record of settings at compiletime
ic.f90 - Pre/Post-processing template.
describe_state.f90 - check time/parameters; see also main.info for outputs.
changeMp.f90 - change i_Mp value in a state file.
change_Mp_alpha.f90 - make copies of a state, or extract modes, dependent on changes in length or azimuthal symmetry.
prim2matlab.f90 - extract data and write in a netcdf format for easy loading into Matlab or VisIt.

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

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