template<class ArrayT>
| static void Impala::Core::Array::Pattern::PxScatterArrayMPI | ( | ArrayT * | glob, | |
| ArrayT * | loc, | |||
| int | root, | |||
| int | bdata = true | |||
| ) | [inline, static] |
Definition at line 753 of file PxDistribution.h.
References _myCPU, _nrCPUs, ArrayBD(), ArrayBH(), ArrayBW(), ArrayD(), ArrayH(), ArrayPB(), ArrayW(), PxLclDepth(), PxLclHeight(), and PxLclWidth().
Referenced by PxScatterArray().
00754 { 00755 /*** MPI-Scatter. May be faster than OFT/SBT scatter provided ***/ 00756 /*** above as specific communication subsystem capabilities may ***/ 00757 /*** be incorporated in the implementation. ***/ 00758 /*** ***/ 00759 /*** NOTE: This function can only be used if: ***/ 00760 /*** ***/ 00761 /*** Borders must be sent as well OR all border sizes are 0 AND ***/ 00762 /*** xcpus>=1 AND ArrayH(glob)=1 AND ArrayD(glob)=1, OR ***/ 00763 /*** xcpus=1 AND ycpus>=1 AND ArrayD(glob)=1, OR ***/ 00764 /*** xcpus=1 AND ycpus=1 AND zcpus>=1. ***/ 00765 /*** ***/ 00766 /*** This is due to the lack of possibility to define an array ***/ 00767 /*** of derived datatypes at the root. In principle, we could ***/ 00768 /*** temporarily re-arrange the layout of the array to still be ***/ 00769 /*** able to use the standard MPI functionality. However, this ***/ 00770 /*** requires a costly copy operation which is not implemented. ***/ 00771 00772 int *counts, *disps; 00773 00774 /*** Determine size and position of each local array ***/ 00775 00776 if (_myCPU == root) { 00777 counts = new int[_nrCPUs]; 00778 disps = new int[_nrCPUs]; 00779 int slice = 2*((ArrayW(glob)*ArrayH(glob)*ArrayBD(glob)) + 00780 (ArrayW(glob)*ArrayBH(glob))); 00781 for (int i=0; i<_nrCPUs; i++) { 00782 counts[i] = (PxLclWidth(i) + 2*ArrayBW(glob)) * 00783 (PxLclHeight(i) + 2*ArrayBH(glob)) * 00784 (PxLclDepth(i) + 2*ArrayBD(glob)); 00785 disps[i] = (i==0) ? 0 : disps[i-1] + counts[i-1] - slice; 00786 } 00787 } 00788 00789 /*** Scatter array data ***/ 00790 00791 int sSize = ArrayT::ElemSize()*sizeof(typename ArrayT::StorType); 00792 MPI_Datatype elem; 00793 MPI_Type_contiguous(sSize, MPI_BYTE, &elem); 00794 MPI_Type_commit(&elem); 00795 MPI_Scatterv(ArrayPB(glob), counts, disps, elem, ArrayPB(loc), 00796 ArrayW(loc)*ArrayH(loc)*ArrayD(loc), elem, root, 00797 MPI_COMM_WORLD); 00798 MPI_Type_free(&elem); 00799 00800 if (_myCPU == root) { 00801 delete counts; 00802 delete disps; 00803 } 00804 }
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