High Performance Computing 1
Parallel MG
•On levels k >= i >= 1, this effect disappears, because each processor needs to communicate about as many words as it does floating point operations:
•
•Time at level i = O( 1 ) * f        ... number of flops, proportional
•                                                   to # of grid points per processor
•                          + O( 1 ) * alpha   ... send a constant number of
•                                                           messages to neighbors
•                          + O( 1 ) * beta      ... number of words sent