A call to the ScaLAPACK TOOLS routine SL_INIT initializes
the process grid. This routine initializes a
(denoted
in the source code)
process grid by using a row-major ordering of the processes, and obtains
a default system context .
For more information on contexts, refer to section 4.1.2
or [54].
The user can then query the process grid to identify each process's coordinates (MYROW,MYCOL) ) via a call to BLACS_GRIDINFO .
A typical code fragment (as obtained from the example program in section 2.3) to accomplish this task would be the following:
CALL SL_INIT( ICTXT, NPROW, NPCOL ) CALL BLACS_GRIDINFO( ICTXT, NPROW, NPCOL, MYROW, MYCOL )
where details of the calling sequence for SL_INIT are provided below. Detailed descriptions of calling sequences for each BLACS routine can be found in [54] and Appendix D.3. Note that underlined arguments in the calling sequence denote output arguments.
For a description of these variables names, please refer to the example program notation in section 2.3 and [54].