Example: Parallel Region in FORTRAN

• Compiler directives are enabled with the -mp switch or -apo switch. With -apo automatic parallelization is requested.

• • In this example all loops can be made parallel automatically (-apo)

SUBROUTINE MXM(A,B,C,LM,M,N,N1)

DIMENSION A(M,L), B(N1,M), C(N1,L)

DO 100 K=1,L

DO 100 I=1,N

C(I,K) = 0.0

100 CONTINUE

C$OMP PARALLEL DO

DO 110 K=1,L

DO 110 I=1,N

DO 110 J=1,M

C(I,K) = C(I,K) + B(I,J)*A(J,K)

110 CONTINUE

END

Will be run serially, unless

-apo is specified

Default variable type association rules:

all variables shared (I.e. A,B,C are shared)

Induction variables I,J,K will be found

automatically and assigned private scope

Previous slide

Next slide

Back to first slide

View graphic version