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| author | Remko Tronçon <git@el-tramo.be> | 2012-04-23 13:32:24 (GMT) |
|---|---|---|
| committer | Remko Tronçon <git@el-tramo.be> | 2012-04-23 13:57:24 (GMT) |
| commit | 18f4f0ba13bbfe901dae44e95d869ba0425e93c7 (patch) | |
| tree | 51de477a7f2dc9aba3177e6ea50ed90dbff91f85 /Swiften/Base/BoostRandomGenerator.cpp | |
| parent | 2f64443e7a3e427a3a38665b5aafb77c9b128cc0 (diff) | |
| download | swift-18f4f0ba13bbfe901dae44e95d869ba0425e93c7.zip swift-18f4f0ba13bbfe901dae44e95d869ba0425e93c7.tar.bz2 | |
Select SRV randomly, taking weight into account.
Resolves: #1030
Diffstat (limited to 'Swiften/Base/BoostRandomGenerator.cpp')
| -rw-r--r-- | Swiften/Base/BoostRandomGenerator.cpp | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/Swiften/Base/BoostRandomGenerator.cpp b/Swiften/Base/BoostRandomGenerator.cpp new file mode 100644 index 0000000..b8c50d0 --- /dev/null +++ b/Swiften/Base/BoostRandomGenerator.cpp @@ -0,0 +1,27 @@ +/* + * Copyright (c) 2012 Remko Tronçon + * Licensed under the GNU General Public License v3. + * See Documentation/Licenses/GPLv3.txt for more information. + */ + +#include <Swiften/Base/BoostRandomGenerator.h> + +#include <numeric> +#include <boost/random/uniform_real.hpp> +#include <boost/random/variate_generator.hpp> + +namespace Swift { + +int BoostRandomGenerator::generateWeighedRandomNumber(std::vector<double>::const_iterator probabilities_begin, std::vector<double>::const_iterator probabilities_end) { + // Only works starting boost 1.47 + //boost::random::discrete_distribution<> distribution(weights.begin(), weights.end()); + //return distribution(generator); + + std::vector<double> cumulative; + std::partial_sum(probabilities_begin, probabilities_end, std::back_inserter(cumulative)); + boost::uniform_real<> dist(0, cumulative.back()); + boost::variate_generator<boost::mt19937&, boost::uniform_real<> > die(generator, dist); + return std::lower_bound(cumulative.begin(), cumulative.end(), die()) - cumulative.begin(); +} + +} |