Cost Estimation for Divide-and-Conquer Programs

• A significant shortcoming of the approach to cost estimation presented in the last period is that the size of each argument in the body was treated as a function of the input sizes of the head, independent of the sizes of other arguments in the body.
• As a result, relationships between the sizes of different body arguments were lost.
• This, in turn, can cause a significant loss in precision, especially in divide-and-conquer programs in which the size of the ``divide'' predicates are dependent.
• As a pragmatic short-term solution, it may be possible to get a lot of mileage simply by identifying and treating divide-and-conquer programs specially.