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authorRemko Tronçon <git@el-tramo.be>2012-04-23 13:32:24 (GMT)
committerRemko Tronçon <git@el-tramo.be>2012-04-23 13:57:24 (GMT)
commit18f4f0ba13bbfe901dae44e95d869ba0425e93c7 (patch)
tree51de477a7f2dc9aba3177e6ea50ed90dbff91f85 /Swiften/Base/BoostRandomGenerator.cpp
parent2f64443e7a3e427a3a38665b5aafb77c9b128cc0 (diff)
downloadswift-contrib-18f4f0ba13bbfe901dae44e95d869ba0425e93c7.zip
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Select SRV randomly, taking weight into account.
Resolves: #1030
Diffstat (limited to 'Swiften/Base/BoostRandomGenerator.cpp')
-rw-r--r--Swiften/Base/BoostRandomGenerator.cpp27
1 files changed, 27 insertions, 0 deletions
diff --git a/Swiften/Base/BoostRandomGenerator.cpp b/Swiften/Base/BoostRandomGenerator.cpp
new file mode 100644
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+++ b/Swiften/Base/BoostRandomGenerator.cpp
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+/*
+ * 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();
+}
+
+}