Screen Output

As your Cactus executable runs, standard output and standard error are usually written to the screen. Standard output provides you with information about the run, and standard error reports warnings and errors from the flesh and thorns.

As the program runs, the normal output provides the following information:

Active thorns

A report is made as each of the thorns in the ActiveThorns parameters from the parameter file (see Section A3.2) is attempted to be activated. This report shows whether the thorn activation was successful, and if successful, gives the thorn's implementation. For example,

Activating thorn idscalarwave...Success -> active implementation idscalarwave

Failed parameters

If any of the parameters in the parameter file does not belong to any of the active thorns, or if the parameter value is not in the allowed range (see Section B5.1), an error is registered. For example, if the parameter is not recognised,

Unknown parameter time::ddtfac

or if the parameter value is not in the allowed range,

Unable to set keyword CartGrid3D::type - ByMouth not in any active range

Scheduling information

The scheduled routines (see Section B6) are listed in the order that they will be executed. For example,

----------------------------------------------------------------------
  Startup routines
    Cactus: Register banner for Cactus
    CartGrid3D: Register GH Extension for GridSymmetry
    CartGrid3D: Register coordinates for the Cartesian grid
    IOASCII: Startup routine
    IOBasic: Startup routine
    IOUtil: IOUtil startup routine
    PUGH: Startup routine
    WaveToyC: Register banner

  Parameter checking routines
    CartGrid3D: Check coordinates for CartGrid3D
    IDScalarWave: Check parameters

  Initialisation
    CartGrid3D: Set up spatial 3D Cartesian coordinates on the GH
    PUGH: Report on PUGH set up
    Time: Set timestep based on speed one Courant condition
    WaveToyC: Schedule symmetries
    IDScalarWave: Initial data for 3D wave equation

  do loop over timesteps
    WaveToyC: Evolution of 3D wave equation
    t = t+dt
    if (analysis)
    endif
  enddo
----------------------------------------------------------------------

Thorn banners

Usually a thorn registers a short piece of text as a banner. The banner of each thorn is displayed in the standard output when the thorn is initialised.