Design space heuristic

The design space is explored using either an exact or a heuristic search of the assignments, using cost criteria that include area, interconnection, and delay. 

Before describing the design space exploration strategy, we introduce first the concept of concurrency factor to measure of the degree of parallelism among subsets of shareable operations Q Q V. This concept is used extensively in resource allocation and heuristic exploration of the design space. 

Using the conflict-free allocation as guideline, a set of resource allocations ai,...,afc is specified either by the user manually or by the system automatically. Hebe supports both exact and heuristic strategies to explore the design space they are summarized below. 

Pruning ensures that pruned allocations or bindings always violate the required timing constraints. However, many bindings may still result even after pruning. This leads to the heuristic design space exploration strategy, described in the next section. 

For some designs, exact exploration of the design space may be prohibitive due to its size. Hebe also supports heuristic strategies to explore the design space, where the resulting implementation is no longer guaranteed to be optimal. 

Figure 5.11 Block diagram of subspace generation strategy for heuristic design space exploration.

Figure 5.12 Heuristic design space generation for 6 operations to 2 resources 3 disjoint groups are formed, resulting in three bindings.

Figure 5.13 Block diagram of the design space ranking strategy in heuristic design space exploration.

The heuristic design space exploration and conflict resolution strategy was... 

The set of candidate solutions considered by a search procedure is often called the search space of the problem. For molecular design problems, there are several possible search spaces, the most common being sequence space, the space of all molecules being considered [4,37-39], The concept of a sequence space is important because it provides a framework for formal theory and it has heuristic value in developing intuition for searches and communicating ideas. Sequence spaces are discrete, though search spaces in general may be discrete, continuous, or discrete on some axes and continuous on others. 

The separation in space principle needs to be used when dealing with requirements and constraints related to the spatial aspects of design. For example, an inventor is working on a concept for a snowmobile to be used behind the Arctic Circle to transport frozen seafood. The traditional thinking about designing commercial vehicles for the Arctic Circle is simple Insulate the entire vehicle as much as possible. In our case, this heuristic is simply inadequate and we need to use the separation in space principle. 

A top-level design is illustrated in Fig. 3. Note that local search is applied to many steps including constmction heuristics, crossover, mutation, and selection. This is to prevent any unexploited space missed in each of the global search heuristic steps. 

---