There are no other sources of overhead. . This algorithm partitions all the computation but introduces an additional cost of 100. . This algorithm also partitions all the computation but introduces an additional cost of . However, they behave differently in other situations, as illustrated in Figure 3.1 . Notice the use of logarithmic scales.
Asymptotic analysis reveals that the algorithm requires time on processors.
While this information is interesting, it is often not directly relevant to the task of developing an efficient parallel program. Because it deals with large N and P , it ignores lower-order terms that may be significant for problem sizes and processor counts of practical interest. A second deficiency of asymptotic analysis is that it says nothing about absolute cost. N is superior to an algorithm with cost . For example, they may assume the PRAM model, in which communication costs are assumed to be nil.