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JCL v. GPS

      JCL and GPS are two heuristic algorithms. GPS source code (i.e., 582.for) is a public domain software. Both JCL and GPS are in Fortran. The following is a comparison of JCL and GPS on the examples in "Algorithms for reducing the bandwidth and profile of a sparse matrix", published in computers & structures, vol. 44, no. 3, 1992. The OPTPRO option of GPS is set to False which means bandwidth reduction has a higher priority.

Example Bandwidth
Figure n JCL GPS Winner
4 25 5 5
5 36 7 8 JCL
6 48 8 8
7 72 6 6
8 145 12 13 JCL
9 34 8 8
10 108 7 10 JCL
11 131 8 8
12 49 10 12 JCL
13 62 4 5 JCL
14 66 8 13 JCL
15 37 6 7 JCL


Example Profile
Figure n JCL GPS Winner
4 25 88 88
5 36 130 136 JCL
6 48 253 219 GPS
7 72 267 282 JCL
8 145 1024 1024
9 34 160 166 JCL
10 108 441 491 JCL
11 131 746 750 JCL
12 49 331 322 GPS
13 62 135 149 JCL
14 66 270 309 JCL
15 37 117 111 GPS

      From the above comparison, it can be seen that JCL completely beats GPS in bandwidth reduction. In profile reduction, JCL wins 7, and GPS has 3. Even JCL is bandwidth-reduction based, JCL is still better than GPS in profile reduction.

      JCL is a reliable heuristic algorithm. Even JCL outperforms GPS, GPS has been wide-applied in scientific and engineering computing. There are some research papers comparing "average bandwidth" to GPS's bandwidth reduction. This site believes it is not a fair comparison. GPS's concept is to stretch a level structure to a maximal depth. A maximal-depth level structure is for a minimal bandwidth, not a minimal "average bandwidth". "Average bandwidth" belongs to the scope of profile reduction. It is inappropriate to compare a profile reduction algorithm to a bandwidth reduction algorithm. This site compares JCL with GPS, both of which are bandwidth reduction algorithm.