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26 <div class="titlepage"><div><div><h3 class="title">
27 <a name="boost_multiprecision.perf.int_real_world"></a><a class="link" href="int_real_world.html" title="Integer Real World Tests">Integer Real
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31 The first set of <a href="../../../../performance/voronoi_performance.cpp" target="_top">tests</a>
32 measure the times taken to execute the multiprecision part of the Voronoi-diagram
33 builder from Boost.Polygon. The tests mainly create a large number of temporaries
34 "just in case" multiprecision arithmetic is required, for comparison,
35 also included in the tests is Boost.Polygon's own partial-multiprecision
36 integer type which was custom written for this specific task:
38 <div class="informaltable"><table class="table">
51 Relative Performance (Actual time in parenthesis)
59 polygon::detail::extended_int
179 Note how for this use case, any dynamic allocation is a performance killer.
182 The next <a href="../../../../performance/miller_rabin_performance.cpp" target="_top">tests</a>
183 measure the time taken to generate 1000 128-bit random numbers and test for
184 primality using the Miller Rabin test. This is primarily a test of modular-exponentiation
185 since that is the rate limiting step:
187 <div class="informaltable"><table class="table">
200 Relative Performance (Actual time in parenthesis)
220 cpp_int (no Expression templates)
232 cpp_int (128-bit cache)
244 cpp_int (256-bit cache)
256 cpp_int (512-bit cache)
268 cpp_int (1024-bit cache)
316 mpz_int (no Expression templates)
340 tom_int (no Expression templates)
352 It's interesting to note that expression templates have little effect here
353 - perhaps because the actual expressions involved are relatively trivial
354 in this case - so the time taken for multiplication and division tends to
355 dominate. Also note how increasing the internal cache size used by <code class="computeroutput"><span class="identifier">cpp_int</span></code> is quite effective in this case
356 in cutting out memory allocations altogether - cutting about a third off
357 the total runtime. Finally the much quicker times from GMP and tommath are
358 down to their much better modular-exponentiation algorithms (GMP's is about
359 5x faster). That's an issue which needs to be addressed in a future release
360 for <a class="link" href="../tut/ints/cpp_int.html" title="cpp_int">cpp_int</a>.
363 Test code was compiled with Microsoft Visual Studio 2010 with all optimisations
364 turned on (/Ox), and used MPIR-2.3.0 and <a href="http://www.mpfr.org" target="_top">MPFR</a>-3.0.0.
365 The tests were run on 32-bit Windows Vista machine.
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370 <td align="right"><div class="copyright-footer">Copyright © 2002-2013 John Maddock and Christopher Kormanyos<p>
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