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2. Filtered databases:

If we only consider execution times, the filtered databases have similar results, though not presented here, as the sampled databases. But since the constraint systems are of larger sizes, we expect to have a different picture concerning the exceptions.

In fact, 6_tab:PerfectClub_satisfiability_64_32_exception_filter shows that $C^3$ Simplex 64-bit has reduced from $92$ exceptions to $2$ exceptions compared to its version 32-bit. The Double Description method 32-bit raises $50$ overflow exceptions among which $36$ timeout exceptions, i.e. $407 - 371$, are expected using its 64-bit version.


Table 14: PerfectClub: Numbers of exceptions in filtered database
  PerfectClub
timeout = 2 minutes #overflows #timeouts #operations
$C^3$ JANUS 64-bit 0 0 1310
$C^3$ JANUS 32-bit 0 0 1310
$C^3$ Simplex 64-bit 2 0 1310
$C^3$ Simplex 32-bit 92 0 1310
$C^3$ Fourier-Motzkin 64-bit 0 0 1310
$C^3$ Fourier-Motzkin 32-bit 0 0 1310
$C^3$ Double Description 64-bit 0 407 1310
$C^3$ Double Description 32-bit 50 371 1310


6_tab:SPEC95_satisfiability_64_32_exception_filter shows that using 32-bit instead of 64-bit results in many more overflow exceptions. The Double Description method has the biggest difference: $939$ to $22$.


Table 15: SPEC95: Numbers of exceptions in filtered database
  SPEC95
timeout = 2 minutes #overflows #timeouts #operations
$C^3$ JANUS 64-bit 3050 0 4676
$C^3$ JANUS 32-bit 3109 0 4676
$C^3$ Simplex 64-bit 3174 0 4676
$C^3$ Simplex 32-bit 3972 0 4676
$C^3$ Fourier-Motzkin 64-bit 8 625 4676
$C^3$ Fourier-Motzkin 32-bit 181 495 4676
$C^3$ Double Description 64-bit 22 0 4676
$C^3$ Double Description 32-bit 939 0 4676



previous_group previous up next next_group
Previous: 1. Sampled databases: Up: 6. Arithmetic Precision: 64-bit Next: 7. Conclusion
Nguyen Que Duong
2006-09-16