6 Preparing Input Files

The Multiblock framework reads its description of the problem domain from input "block" files, which are in a Multiblock-specific format. The files are named with the pattern prefixnumber.ext, where prefix is a arbitrary string prefix you choose; number is the number of this block (virtual processor); and ext is either ``mblk'', which contains binary data with the block coordinates, or ``bblk'', which contains ASCII data with the block's boundary conditions.

You generate these Multiblock input files using a tool called makemblock, which can be found in charm/version/pgms/charm++/makemblock. makemblock can read a description of the problem domain generated by the structured meshing program Gridgen (from Pointwise) in .grd and .inp format; or read a binary .msh format. makemblock divides this input domain into the number of blocks you specify, then writes out .mblk and .bblk files.

For example, to divide the single binary mesh ``in1.msh'' into 20 pieces ``out00001.[mb]blk''..``out00020.[mb]blk'', you'd use

	makemblock in1.msh 20 out

You would then run this mesh using 20 virtual processors.