r177:b685e12e08c0
Thu, 19 Jun 2008 10:59:22
[Not Reviewed]
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@@ -57,28 +57,38 @@ |
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* Any feedback is very welcome. |
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* http://www.math.sci.hiroshima-u.ac.jp/~m-mat/MT/emt.html |
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* email: m-mat @ math.sci.hiroshima-u.ac.jp (remove space) |
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*/ |
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|
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#ifndef LEMON_RANDOM_H |
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#define LEMON_RANDOM_H |
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#include <algorithm> |
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#include <iterator> |
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#include <vector> |
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#include <limits> |
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#include <fstream> |
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#include <lemon/math.h> |
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#include <lemon/dim2.h> |
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#ifndef WIN32 |
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#include <sys/time.h> |
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#include <ctime> |
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#include <sys/types.h> |
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#include <unistd.h> |
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#else |
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#include <windows.h> |
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#endif |
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///\ingroup misc |
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///\file |
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///\brief Mersenne Twister random number generator |
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|
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namespace lemon {
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namespace _random_bits {
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template <typename _Word, int _bits = std::numeric_limits<_Word>::digits> |
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struct RandomTraits {};
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template <typename _Word> |
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@@ -517,24 +527,28 @@ |
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class Random {
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private: |
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// Architecture word |
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typedef unsigned long Word; |
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_random_bits::RandomCore<Word> core; |
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_random_bits::BoolProducer<Word> bool_producer; |
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public: |
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///\name Initialization |
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/// |
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/// @{
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/// \brief Default constructor |
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/// |
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/// Constructor with constant seeding. |
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Random() { core.initState(); }
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/// \brief Constructor with seed |
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/// |
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/// Constructor with seed. The current number type will be converted |
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/// to the architecture word type. |
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template <typename Number> |
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Random(Number seed) {
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_random_bits::Initializer<Number, Word>::init(core, seed); |
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@@ -585,24 +599,91 @@ |
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/// \brief Seeding random sequence |
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/// |
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/// Seeding the random sequence. The given range should contain |
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/// any number type and the numbers will be converted to the |
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/// architecture word type. |
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template <typename Iterator> |
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void seed(Iterator begin, Iterator end) {
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typedef typename std::iterator_traits<Iterator>::value_type Number; |
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_random_bits::Initializer<Number, Word>::init(core, begin, end); |
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} |
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/// \brief Seeding from file or from process id and time |
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/// |
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/// By default, this function calls the \c seedFromFile() member |
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/// function with the <tt>/dev/urandom</tt> file. If it is not success, |
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/// it uses the \c seedFromTime(). |
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/// \return Currently always true. |
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bool seed() {
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#ifndef WIN32 |
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if (seedFromFile("/dev/urandom", 0)) return true;
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#endif |
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if (seedFromTime()) return true; |
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return false; |
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} |
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|
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/// \brief Seeding from file |
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/// |
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/// Seeding the random sequence from file. The linux kernel has two |
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/// devices, <tt>/dev/random</tt> and <tt>/dev/urandom</tt> which |
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/// could give good seed values for pseudo random generators (The |
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/// difference between two devices is that the <tt>random</tt> may |
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/// block the reading operation while the kernel can give good |
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/// source of randomness, while the <tt>urandom</tt> does not |
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/// block the input, but it could give back bytes with worse |
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/// entropy). |
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/// \param file The source file |
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/// \param offset The offset, from the file read. |
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/// \return True when the seeding is success. |
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#ifndef WIN32 |
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bool seedFromFile(const std::string& file = "/dev/urandom", int offset = 0) |
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#else |
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bool seedFromFile(const std::string& file = "", int offset = 0) |
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#endif |
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{
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std::ifstream rs(file.c_str()); |
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const int size = 4; |
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Word buf[size]; |
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if (offset != 0 && !rs.seekg(offset)) return false; |
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if (!rs.read(reinterpret_cast<char*>(buf), sizeof(buf))) return false; |
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seed(buf, buf + size); |
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return true; |
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} |
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/// \brief Seding from process id and time |
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/// |
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/// Seding from process id and time. This function uses the |
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/// current process id and the current time for initialize the |
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/// random sequence. |
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/// \return Currently always true. |
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bool seedFromTime() {
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#ifndef WIN32 |
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timeval tv; |
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gettimeofday(&tv, 0); |
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seed(getpid() + tv.tv_sec + tv.tv_usec); |
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#else |
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FILETIME time; |
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GetSystemTimeAsFileTime(&time); |
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seed(GetCurrentProcessId() + time.dwHighDateTime + time.dwLowDateTime); |
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#endif |
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return true; |
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} |
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/// @} |
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///\name Uniform distributions |
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/// |
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/// @{
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/// \brief Returns a random real number from the range [0, 1) |
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/// |
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/// It returns a random real number from the range [0, 1). The |
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/// default Number type is \c double. |
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template <typename Number> |
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Number real() {
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return _random_bits::RealConversion<Number, Word>::convert(core); |
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} |
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double real() {
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return real<double>(); |
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} |
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@@ -700,24 +781,26 @@ |
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return integer<int>(); |
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} |
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/// \brief Returns a random bool |
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/// |
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/// It returns a random bool. The generator holds a buffer for |
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/// random bits. Every time when it become empty the generator makes |
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/// a new random word and fill the buffer up. |
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bool boolean() {
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return bool_producer.convert(core); |
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} |
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/// @} |
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///\name Non-uniform distributions |
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/// |
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///@{
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/// \brief Returns a random bool |
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/// |
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/// It returns a random bool with given probability of true result. |
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bool boolean(double p) {
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return operator()() < p; |
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} |
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