Intel® oneAPI Math Kernel Library Developer Reference - C
Sets values that BLACS use for internal defaults.
call blacs_set( icontxt, what, val )
icontxt |
INTEGER. For values of what that are tied to a particular context, this parameter is the integer handle indicating the context. Otherwise, ignored. |
what |
INTEGER. Indicates what BLACS internal(s) should be set. Present values are:
|
val |
INTEGER. Array of dimension (*). Indicates the value(s) the internals should be set to. The specific meanings depend on what values. |
This routine sets the BLACS internal defaults depending on what values:
Setting the BLACS message ID range.
If you wish to mix the BLACS with other message-passing packages, restrict the BLACS to a certain message ID range not to be used by the non-BLACS routines. The message ID range must be set before the first call to blacs_gridinit or blacs_gridmap. Subsequent calls will have no effect. Because the message ID range is not tied to a particular context, the parameter icontxt is ignored, and val is defined as:
VAL (input) INTEGER array of dimension (2)
VAL(1) : The smallest message ID (also called message type or message tag) the BLACS should use.
VAL(2) : The largest message ID (also called message type or message tag) the BLACS should use.
Set number of rings for TOP = 'M' (multiring broadcast).This quantity is tied to a context, so icontxt is used, and val is defined as:
VAL (input) INTEGER array of dimension (1)
VAL(1) : The number of rings for multiring topology to use.
Set number of branches for TOP = 'T' (general tree broadcast). This quantity is tied to a context, so icontxt is used, and val is defined as:
VAL (input) INTEGER array of dimension (1)
VAL(1) : The number of branches for general tree topology to use.
Set number of rings for TOP = 'M' (multiring combine).This quantity is tied to a context, so icontxt is used, and val is defined as:
VAL (input) INTEGER array of dimension (1)
VAL(1) : The number of rings for multiring topology to use.
Set number of branches for TOP = 'T' (general tree gather). This quantity is tied to a context, so icontxt is used, and val is defined as:
VAL (input) INTEGER array of dimension (1)
VAL(1) : The number of branches for general tree topology to use.
Force topologies to be repeatable or not (see Repeatability and Coherence for more information about repeatability).
VAL (input) INTEGER array of dimension (1)
VAL(1) = 0 (default) |
Topologies are not required to be repeatable. |
VAL(1) ≠ 0 |
All used topologies are required to be repeatable, which might degrade performance. |
Force topologies to be heterogenous coherent or not (see Repeatability and Coherence for more information about coherence).
VAL (input) INTEGER array of dimension (1)
VAL(1) = 0 (default) |
Topologies are not required to be heterogenous coherent. |
VAL(1) ≠ 0 |
All used topologies are required to be heterogenous coherent, which might degrade performance. |