For developers

All svn account holders need to familiarize themselves with the following rules.

Rules for contributing your code to be included in the SELFE package

Here are some rules for preparing your own code:

• Name all your parallel codes .F90;
• No spaces between “#” (pre-processor) and if/else/end;
• Try to use the I/O channel number directly, e.g., read(61, etc instead of assigning a number to a variable (e.g. read(ich,). This'd facilitate others searching for conflicts.

Sharing I/O channels in SELFE

You need to exercise caution when dealing with parallel I/O especially for writing. For writing outputs, you’d generally let only 1 process do the job, e.g.

if(myrank==0) write(10,*)…..

If you do need to have all processes write e.g. debug messages, you’d then use channel 12 (see below).

Below are all I/O channel numbers used in different sub-models of SELFE (bold numbers mean they have been used by other sub-models and you’d avoid using them). Please add your numbers as soon as you change the code so as to prevent others from using it. A good way to find out if a number is available is to issue the following cmd from src/:

grep "61" */*.F90 -->Looks for '61'

• Hydro/: Channels between 8 and 200 are used by various codes for I/O. In particular:
  • 12: this channel is initialized by different processes to point to files outputs/nonfatal_xxxx, where “xxxx” are the process IDs. Therefore it’s very useful for debugging purpose; you can use it anywhere
  • 101 to 100+noutput (inclusive of both): reserved for global outputs (including from tracers from sediment, EcoSim, ICM, as well as WWM);
  • 201-250: non-standard outputs (e.g. at sidecenters, prism centers);
  • 251 to 259: reserved for station outputs
  • 10, 31, 32: used for one-off I/O – can be used by other sub-models as long as you close them immediately after use in your part of the code
  • 16: this channel points to mirror.out (on rank 0), the main message output for info about the run. You should use it with if(myrank==0)
• WWM
  • 1100 to 1200: handles for inputs/outputs etc
• EcoSim
  • 600: outputting some messages
• ICM
  • 301 to 323: reading channels for non-point source inputs for ICM
• Sediment
  • 5 and 10 (both for temporary reading)
• Sed2D
  • 26

Custom timer

If you need to profile some parts of the code, you can use the custom timer: timer_ns(). Here are the steps to set up a new timer:

• In Core/elfe_glbl.F90: increase the dimension of timer_ns() for your number of timers needed;
• Insert the following segments around the portion of the code you want to profile:

#ifdef INCLUDE_TIMING

    cwtmp2=mpi_wtime() !start of timer

#endif ......

#ifdef INCLUDE_TIMING

     timer_ns(id)=timer_ns(id)+mpi_wtime()-cwtmp2 !end timing this section

#endif

('id' is the index of your timer)

• Compile with USE_TIMER turned on in Make.defs.<your env>
• The outputs can be found in: outputs/nonfatal_*; search for 'Custom timers in hours:'. You can sickle them together with:

grep "Custom timers in hours: <id>" outputs/nonfatal_* > mytimer.<id>

On many clusters, more sophisticated profilers exist. Check your local system.