Browsing by Subject "Hypercube topology"

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Open Access
Parallel maze routing algorithms on a hypercube multicomputer
(1991) Kurç, Tahsin Mertefe
Global routing phase is a time consuming task in VLSI layout. In global routing phase of the layout problem, the overall objective is to realize all the net interconnections using shortest paths. Efficient heuristics are used for the global routing phase. However, clue to the assumptions and constraints they impose, heuristics may fail to find a path for a net even if one exists. Re-routing is required for such nets. This re-routing phase requires the exhaustive search of the wiring area. Lee’s maze routing algorithm and Lee type maze routing algorithms are exhaustive search algorithms used in re-routing phase. These algorithms are computationally expensive algorithms and consume large amounts of computer time for large grid sizes. Hence, these algorithms are good candidates for parallelization. Also, these algorithms require large memory space to hold the wiring grid. Therefore, the effective parallelization of these algorithms require the partitioning of the computations and the grid among the processors. Hence, these algorithms can be parallelized on distributed-memory message passing multiprocessors (multicomputers). In this work, efficient parallel Lee type maze routing algorithms are developed for hypercube-connected multi computers. These algorithms are implemented on an Intel’s iPSC/2 hypercube multicomputer.
Open Access
Spatial subdivision for parallel ray casting/tracing
(1995) İşler, Veysi
Ray casting/tracing has been extensively studied for a long time, since it is an elegant way of producing realistic images. However, it is a computationally intensive algorithm. In this study, a taxonomy of parallel ray casting/tracing algorithms is presented cind the primary parallel ray casting/tracing systems are discussed and criticized. This work mainly focuses on the utilization of spatial subdivision technique for ray casting/tracing on a distributed-memory MIMD parallel computer. In this research, the reason for the use of parallel computers is not only the processing power but also the large memory space provided by them. The spatial subdivision technique has been adapted to parallel ray casting/tracing to decompose a three-dimensional complex scene that may not fit into the local memory of a single processor. The decomposition method achieves an even distribution of scene objects while allowing to exploit graphical coherence. Additionally, the decomposition method produces three-dimensional volumes which are mapped inexpensively to the processors so that the objects within adjacent volumes are stored in the local memories of close processors to decrease interprocessor communication cost. Then, the developed decomposition and mapping methods have been parallelized efficiently to reduce the preprocessing overhead. Finally, a splitting plane concept (called “jaggy splitting plane”) has been proposed to accomplish full utilization of the memory space of processors. Jaggy splitting plane avoids the shared objects which are the major sources of inefficient utilization of both memory and processing power. The proposed parallel algorithms have been implemented on the Intel iPSC/2 hypercube multicomputer (distributed-memory MIMD).