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Diffstat (limited to 'src/include/Distribution.h')
-rw-r--r-- | src/include/Distribution.h | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/src/include/Distribution.h b/src/include/Distribution.h new file mode 100644 index 00000000..e4f0b30b --- /dev/null +++ b/src/include/Distribution.h @@ -0,0 +1,73 @@ +// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- +// vim: ts=8 sw=2 smarttab +/* + * Ceph - scalable distributed file system + * + * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net> + * + * This is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License version 2.1, as published by the Free Software + * Foundation. See file COPYING. + * + */ + + +#ifndef CEPH_DISTRIBUTION_H +#define CEPH_DISTRIBUTION_H + +#include <vector> + +class Distribution { + vector<float> p; + vector<int> v; + + public: + //Distribution() { + //} + + unsigned get_width() { + return p.size(); + } + + void clear() { + p.clear(); + v.clear(); + } + void add(int val, float pr) { + p.push_back(pr); + v.push_back(val); + } + + void random() { + float sum = 0.0; + for (unsigned i=0; i<p.size(); i++) { + p[i] = (float)(rand() % 10000); + sum += p[i]; + } + for (unsigned i=0; i<p.size(); i++) + p[i] /= sum; + } + + int sample() { + float s = (float)(rand() % 10000) / 10000.0; + for (unsigned i=0; i<p.size(); i++) { + if (s < p[i]) return v[i]; + s -= p[i]; + } + ceph_abort(); + return v[p.size() - 1]; // hmm. :/ + } + + float normalize() { + float s = 0.0; + for (unsigned i=0; i<p.size(); i++) + s += p[i]; + for (unsigned i=0; i<p.size(); i++) + p[i] /= s; + return s; + } + +}; + +#endif |