D.5 Cray Parallelization Directives

Format

CMIC$ directive qualifiers : initial line

CMIC$& [more_qualifiers] : continuation line

Fixed format. Directive-indicator may be C (as shown here), c, *, or !. With f95 free-format, leading blanks can appear before !MIC$.

DOALL Directive

CMIC$ DOALL SHARED(list), PRIVATE(list) [, more_qualifiers]

Parallelize loop that follows. Qualifiers are: 

Scoping qualifiers are required (unless list is empty)—all variables in the loop must appear in a PRIVATE or SHARED clause:

PRIVATE(list) declare names on list PRIVATE

SHARED(list) declare names on list SHARED

AUTOSCOPE automatically determine scope of variables

The following are optional: 

MAXCPUS(n) use no more than n threads

SAVELAST save last value of all private variables. Only one scheduling qualifier may appear:

GUIDED equivalent to Sun-style GSS(64)

SINGLE equivalent to Sun-style SELF(1)

CHUNKSIZE(n) equivalent to Sun-style SELF(n)

NUMCHUNKS(m) equivalent to Sun-style SELF(n/m)

The default scheduling is Sun-style STATIC, for which there is no Cray-style equivalent. Interpretations of these scheduling qualifiers differ between Sun and Cray style. Check the Fortran Programming Guide for details.

TASKCOMMON Directive

CMIC$ TASKCOMMON block_name

Declares variables in the named common block as thread-private— private to a thread, but global within the thread. Declaring a common block TASKCOMMON requires that this directive appear immediately after every common declaration of that block.

DOSERIAL Directive

CMIC$ DOSERIAL

Disables parallelization of the loop that follows. 

DOSERIAL* Directive

CMIC$ DOSERIAL*

Disables parallelization of the loop nest that follows.