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  • 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.


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.


  • ic.f90 - Pre/Post-processing template.
  • prim2ascii.f90 - extract state data and write an ascii file.
  • 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

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.