3. Arithmetic Precision: 64-bit versus 32-bit

Previous: 2. Overflow and Timeout Up: 6. Results for Dual Next: 4. Conclusion

3. Arithmetic Precision: 64-bit versus 32-bit

6_fig:PerfectClub_dual_conversion_dimension_C3DD64_C3DD32_100 illustrates the comparisons between C3DD64 and C3DD32 for PerfectClub convex hull sampled database. C3DD32 is faster than C3DD64 for all tests with two times faster for total run time.

**Figure 33:** PerfectClub: Dimension C3DD64-bit vs C3DD32-bit in sampled database
$\begin{figure} \centering\epsfig {file=POLYBENCH_evaluations/PerfectClub_C3DD64_... ...ABASE_100/dimension_C3DD64_C3DD32_crite.eps,height=5.9cm,width=14cm}\end{figure}$

As for the CDD implementation, we only have a little difference between CDD64 and CDD32, as demonstrated by 6_fig:PerfectClub_dual_conversion_dimension_CDD64_CDD32_100, for PerfectClub convex hull sampled database. There are cases where CDD64 is faster, but we do not know why.

**Figure 34:** PerfectClub: Dimension CDD64-bit vs CDD32-bit in sampled database
$\begin{figure} \centering\epsfig {file=POLYBENCH_evaluations/PerfectClub_CDD64_C... ...ATABASE_100/dimension_CDD64_CDD32_crite.eps,height=5.9cm,width=14cm}\end{figure}$

6_tab:PerfectClub_dual_conversion_64_32_exception_100 shows that the C3DD and CDD implementations yield no exceptions with PerfectClub convex hull sampled database. There are as well no exceptions for tests in SPEC95 convex hull database.

Table 21: PerfectClub: Numbers of exceptions in sampled database

	PerfectClub
timeout = 2 minutes	#overflows	#timeouts	#operations
C3DD64-bit	0	0	393
C3DD32-bit	0	0	393
CDD64-bit	0	0	393
CDD32-bit	0	0	393

Previous: 2. Overflow and Timeout Up: 6. Results for Dual Next: 4. Conclusion

Nguyen Que Duong
2006-09-16