9.11 Unit Test

The IO unit test is provided to test IO performance on various platforms with the different FLASH IO implementations and parallel libraries.

FLASH3 Transition: The IO unit test replaces the simulation setup io_benchmark in FLASH2.

The unitTest is setup like any other FLASH4 simulation. It can be run with any IO implementation as long as the correct Grid implementation is included. This unitTest writes a checkpoint file, a plotfile, and if particles are included, a particle file. Particles IO can be tested simply by including particles in the simulation. Variables needed for particles should be uncommented in the Config file.

Example setups:

 

#setup for PARAMESH Grid and serial HDF5 io
./setup unitTest/IO -auto


#setup for PARAMESH Grid with parallel HDF5 IO (see shortcuts docs for explanation)
./setup unitTest/IO -auto +parallelIO     (same as)
./setup unitTest/IO -auto -unit=IO/IOMain/hdf5/parallel/PM


#setup for Uniform Grid with serial HDF5 IO, 3d problem, increasing default number of zones
./setup unitTest/IO -3d -auto +ug -nxb=16 -nyb=16 -nzb=16  (same as)
./setup unitTest/IO -3d -auto -unit=Grid/GridMain/UG -nxb=16 -nyb=16 -nzb=16


#setup for PM3 and parallel netCDF, with particles
./setup unitTest/IO -auto -unit=Particles +pnetcdf


#setup for UG and parallel netCDF
./setup unitTest/IO -auto +pnetcdf +ug

Run the test like any other FLASH simulation:  

mpirun -np numProcs flash3

There are a few things to keep in mind when working with the IO unit test:

• The Config file in unitTest/IO declares some dummy grid scope variables which are stored in the unk array. If the user wants a more intensive IO test, more variables can be added. Variables are initialized to dummy values in Driver_evolveFlash.

• Variables will only be output to the plotfile if they are declared in the flash.par (see the example flash.par in the unit test).

• The only units besides the simulation unit included in this simulation are Grid, IO, Driver, Timers, Logfile, RuntimeParameters and PhysicalConstants.

• If the PARAMESH Grid implementation is being used, it is important to note that the grid will not refine on its own. The user should set lrefine_min to a value $>$ 1 to create more blocks. The user could also set the runtime parameters nblockx, nblocky, nblockz to make a bigger problem.

• Just like any other simulation, the user can change the number of zones in a simulation using -nxb=numZones on the setup line.