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C $Header: /u/gcmpack/models/MITgcmUV/eesupp/src/global_sum.F,v 1.2 1998/04/23 20:37:30 cnh Exp $ |
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|
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C-- File global_sum.F: Routines that perform global sum on an array |
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C of thread values. |
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C Contents |
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C o global_sum_r4 |
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C o global_sum_r8 |
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#include "CPP_EEOPTIONS.h" |
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|
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CStartOfInterface |
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SUBROUTINE GLOBAL_SUM_R4( |
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I phi, |
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O sumPhi, |
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I myThid ) |
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C /==========================================================\ |
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C | SUBROUTINE GLOBAL_SUM_R4 | |
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C | o Handle sum for real*4 data. | |
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C |==========================================================| |
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C | Perform sum an array of one value per thread and then | |
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C | sum result of all the processes. | |
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C | Notes | |
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C | ===== | |
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C | Within a process only one thread does the sum, each | |
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C | thread is assumed to have already summed its local data. | |
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C | The same thread also does the inter-process sum for | |
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C | example with MPI and then writes the result into a shared| |
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C | location. All threads wait until the sum is avaiailable. | |
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C \==========================================================/ |
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|
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C == Global data == |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "EESUPPORT.h" |
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|
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C == Routine arguments == |
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C phi - Array to be summed. |
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C sumPhi - Result of sum. |
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C myThid - My thread id. |
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Real*4 phi(lShare4,MAX_NO_THREADS) |
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Real*4 sumPhi |
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INTEGER myThid |
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CEndOfInterface |
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|
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C == Local variables == |
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C I - Loop counters |
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C mpiRC - MPI return code |
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INTEGER I |
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Real*4 tmp |
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#ifdef ALLOW_USE_MPI |
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INTEGER mpiRC |
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#endif /* ALLOW_USE_MPI */ |
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|
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C-- Can't start until everyone is ready |
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_BARRIER |
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|
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C-- Sum within the process first |
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_BEGIN_MASTER( myThid ) |
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tmp = 0. |
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DO I=1,nThreads |
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tmp = tmp + phi(1,I) |
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ENDDO |
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sumPhi = tmp |
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#ifdef ALLOW_USE_MPI |
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#ifndef ALWAYS_USE_MPI |
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IF ( usingMPI ) THEN |
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#endif |
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CALL MPI_Allreduce(tmp,sumPhi,1,MPI_REAL,MPI_SUM, |
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& MPI_COMM_WORLD,mpiRC) |
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#ifndef ALWAYS_USE_MPI |
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ENDIF |
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#endif |
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#endif /* ALLOW_USE_MPI */ |
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phi(1,1) = sumPhi |
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_END_MASTER( myThid ) |
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C-- |
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_BARRIER |
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C |
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RETURN |
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END |
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|
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|
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CStartOfInterface |
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SUBROUTINE GLOBAL_SUM_R8( |
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I phi, |
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O sumPhi, |
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I myThid ) |
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C /==========================================================\ |
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C | SUBROUTINE GLOBAL_SUM_R8 | |
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C | o Handle sum for real*8 data. | |
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C |==========================================================| |
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C | Perform sum an array of one value per thread and then | |
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C | sum result of all the processes. | |
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C | Notes | |
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C | ===== | |
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C | Within a process only one thread does the sum, each | |
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C | thread is assumed to have already summed its local data. | |
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C | The same thread also does the inter-process sum for | |
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C | example with MPI and then writes the result into a shared| |
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C | location. All threads wait until the sum is avaiailable. | |
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C \==========================================================/ |
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|
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C === Global data === |
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#include "SIZE.h" |
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#include "EEPARAMS.h" |
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#include "EESUPPORT.h" |
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|
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C === Routine arguments === |
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C phi - Array to be summed. |
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C sumPhi - Result of sum. |
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C myThid - My thread id. |
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Real*8 phi(lShare8,MAX_NO_THREADS) |
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Real*8 sumPhi |
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INTEGER myThid |
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CEndOfInterface |
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|
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C === Local variables === |
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C I - Loop counters |
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C mpiRC - MPI return code |
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INTEGER I |
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Real*8 tmp |
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#ifdef ALLOW_USE_MPI |
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INTEGER mpiRC |
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#endif /* ALLOW_USE_MPI */ |
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|
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C-- Can't start until everyone is ready |
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_BARRIER |
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|
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C-- Sum within the process first |
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_BEGIN_MASTER( myThid ) |
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tmp = 0. _d 0 |
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DO I=1,nThreads |
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tmp = tmp + phi(1,I) |
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ENDDO |
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sumPhi = tmp |
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#ifdef ALLOW_USE_MPI |
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#ifndef ALWAYS_USE_MPI |
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IF ( usingMPI ) THEN |
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#endif |
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CALL MPI_Allreduce(tmp,sumPhi,1,MPI_DOUBLE_PRECISION,MPI_SUM, |
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& MPI_COMM_WORLD,mpiRC) |
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#ifndef ALWAYS_USE_MPI |
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ENDIF |
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#endif |
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#endif /* ALLOW_USE_MPI */ |
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C-- Write solution to place where all threads can see it |
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phi(1,1) = sumPhi |
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_END_MASTER( myThid ) |
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|
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C-- Don't leave until we are sure that the sum is done |
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_BARRIER |
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C |
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RETURN |
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END |
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