*
* See http://www.boost.org for most recent version including documentation.
*
- * $Id: inversive_congruential.hpp 60755 2010-03-22 00:45:06Z steven_watanabe $
+ * $Id: inversive_congruential.hpp 71018 2011-04-05 21:27:52Z steven_watanabe $
*
* Revision history
* 2001-02-18 moved to individual header files
#ifndef BOOST_RANDOM_INVERSIVE_CONGRUENTIAL_HPP
#define BOOST_RANDOM_INVERSIVE_CONGRUENTIAL_HPP
-#include <iostream>
-#include <cassert>
+#include <iosfwd>
#include <stdexcept>
+#include <boost/assert.hpp>
#include <boost/config.hpp>
-#include <boost/static_assert.hpp>
+#include <boost/cstdint.hpp>
+#include <boost/integer/static_log2.hpp>
#include <boost/random/detail/config.hpp>
#include <boost/random/detail/const_mod.hpp>
+#include <boost/random/detail/seed.hpp>
+#include <boost/random/detail/operators.hpp>
+#include <boost/random/detail/seed_impl.hpp>
+
+#include <boost/random/detail/disable_warnings.hpp>
namespace boost {
namespace random {
// Eichenauer and Lehn 1986
/**
- * Instantiations of class template @c inversive_congruential model a
+ * Instantiations of class template @c inversive_congruential_engine model a
* \pseudo_random_number_generator. It uses the inversive congruential
* algorithm (ICG) described in
*
* not optimal for calculating the multiplicative inverse.
* @endxmlnote
*/
-template<class IntType, IntType a, IntType b, IntType p, IntType val>
-class inversive_congruential
+template<class IntType, IntType a, IntType b, IntType p>
+class inversive_congruential_engine
{
public:
- typedef IntType result_type;
-#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
- static const bool has_fixed_range = true;
- static const result_type min_value = (b == 0 ? 1 : 0);
- static const result_type max_value = p-1;
-#else
- BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
-#endif
- BOOST_STATIC_CONSTANT(result_type, multiplier = a);
- BOOST_STATIC_CONSTANT(result_type, increment = b);
- BOOST_STATIC_CONSTANT(result_type, modulus = p);
-
- result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () const { return b == 0 ? 1 : 0; }
- result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () const { return p-1; }
-
- /**
- * Constructs an inversive_congruential generator with
- * @c y0 as the initial state.
- */
- explicit inversive_congruential(IntType y0 = 1) : value(y0)
- {
- BOOST_STATIC_ASSERT(b >= 0);
- BOOST_STATIC_ASSERT(p > 1);
- BOOST_STATIC_ASSERT(a >= 1);
- if(b == 0)
- assert(y0 > 0);
- }
- template<class It> inversive_congruential(It& first, It last)
- { seed(first, last); }
-
- /** Changes the current state to y0. */
- void seed(IntType y0 = 1) { value = y0; if(b == 0) assert(y0 > 0); }
- template<class It> void seed(It& first, It last)
- {
- if(first == last)
- throw std::invalid_argument("inversive_congruential::seed");
- value = *first++;
- }
- IntType operator()()
- {
- typedef const_mod<IntType, p> do_mod;
- value = do_mod::mult_add(a, do_mod::invert(value), b);
- return value;
- }
-
- static bool validation(result_type x) { return val == x; }
-
-#ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
-
-#ifndef BOOST_RANDOM_NO_STREAM_OPERATORS
- template<class CharT, class Traits>
- friend std::basic_ostream<CharT,Traits>&
- operator<<(std::basic_ostream<CharT,Traits>& os, inversive_congruential x)
- { os << x.value; return os; }
-
- template<class CharT, class Traits>
- friend std::basic_istream<CharT,Traits>&
- operator>>(std::basic_istream<CharT,Traits>& is, inversive_congruential& x)
- { is >> x.value; return is; }
-#endif
+ typedef IntType result_type;
+ BOOST_STATIC_CONSTANT(bool, has_fixed_range = false);
+
+ BOOST_STATIC_CONSTANT(result_type, multiplier = a);
+ BOOST_STATIC_CONSTANT(result_type, increment = b);
+ BOOST_STATIC_CONSTANT(result_type, modulus = p);
+ BOOST_STATIC_CONSTANT(IntType, default_seed = 1);
+
+ static result_type min BOOST_PREVENT_MACRO_SUBSTITUTION () { return b == 0 ? 1 : 0; }
+ static result_type max BOOST_PREVENT_MACRO_SUBSTITUTION () { return p-1; }
+
+ /**
+ * Constructs an @c inversive_congruential_engine, seeding it with
+ * the default seed.
+ */
+ inversive_congruential_engine() { seed(); }
+
+ /**
+ * Constructs an @c inversive_congruential_engine, seeding it with @c x0.
+ */
+ BOOST_RANDOM_DETAIL_ARITHMETIC_CONSTRUCTOR(inversive_congruential_engine,
+ IntType, x0)
+ { seed(x0); }
+
+ /**
+ * Constructs an @c inversive_congruential_engine, seeding it with values
+ * produced by a call to @c seq.generate().
+ */
+ BOOST_RANDOM_DETAIL_SEED_SEQ_CONSTRUCTOR(inversive_congruential_engine,
+ SeedSeq, seq)
+ { seed(seq); }
+
+ /**
+ * Constructs an @c inversive_congruential_engine, seeds it
+ * with values taken from the itrator range [first, last),
+ * and adjusts first to point to the element after the last one
+ * used. If there are not enough elements, throws @c std::invalid_argument.
+ *
+ * first and last must be input iterators.
+ */
+ template<class It> inversive_congruential_engine(It& first, It last)
+ { seed(first, last); }
+
+ /**
+ * Calls seed(default_seed)
+ */
+ void seed() { seed(default_seed); }
+
+ /**
+ * If c mod m is zero and x0 mod m is zero, changes the current value of
+ * the generator to 1. Otherwise, changes it to x0 mod m. If c is zero,
+ * distinct seeds in the range [1,m) will leave the generator in distinct
+ * states. If c is not zero, the range is [0,m).
+ */
+ BOOST_RANDOM_DETAIL_ARITHMETIC_SEED(inversive_congruential_engine, IntType, x0)
+ {
+ // wrap _x if it doesn't fit in the destination
+ if(modulus == 0) {
+ _value = x0;
+ } else {
+ _value = x0 % modulus;
+ }
+ // handle negative seeds
+ if(_value <= 0 && _value != 0) {
+ _value += modulus;
+ }
+ // adjust to the correct range
+ if(increment == 0 && _value == 0) {
+ _value = 1;
+ }
+ BOOST_ASSERT(_value >= (min)());
+ BOOST_ASSERT(_value <= (max)());
+ }
+
+ /**
+ * Seeds an @c inversive_congruential_engine using values from a SeedSeq.
+ */
+ BOOST_RANDOM_DETAIL_SEED_SEQ_SEED(inversive_congruential_engine, SeedSeq, seq)
+ { seed(detail::seed_one_int<IntType, modulus>(seq)); }
+
+ /**
+ * seeds an @c inversive_congruential_engine with values taken
+ * from the itrator range [first, last) and adjusts @c first to
+ * point to the element after the last one used. If there are
+ * not enough elements, throws @c std::invalid_argument.
+ *
+ * @c first and @c last must be input iterators.
+ */
+ template<class It> void seed(It& first, It last)
+ { seed(detail::get_one_int<IntType, modulus>(first, last)); }
+
+ /** Returns the next output of the generator. */
+ IntType operator()()
+ {
+ typedef const_mod<IntType, p> do_mod;
+ _value = do_mod::mult_add(a, do_mod::invert(_value), b);
+ return _value;
+ }
+
+ /** Fills a range with random values */
+ template<class Iter>
+ void generate(Iter first, Iter last)
+ { detail::generate_from_int(*this, first, last); }
+
+ /** Advances the state of the generator by @c z. */
+ void discard(boost::uintmax_t z)
+ {
+ for(boost::uintmax_t j = 0; j < z; ++j) {
+ (*this)();
+ }
+ }
+
+ /**
+ * Writes the textual representation of the generator to a @c std::ostream.
+ */
+ BOOST_RANDOM_DETAIL_OSTREAM_OPERATOR(os, inversive_congruential_engine, x)
+ {
+ os << x._value;
+ return os;
+ }
+
+ /**
+ * Reads the textual representation of the generator from a @c std::istream.
+ */
+ BOOST_RANDOM_DETAIL_ISTREAM_OPERATOR(is, inversive_congruential_engine, x)
+ {
+ is >> x._value;
+ return is;
+ }
+
+ /**
+ * Returns true if the two generators will produce identical
+ * sequences of outputs.
+ */
+ BOOST_RANDOM_DETAIL_EQUALITY_OPERATOR(inversive_congruential_engine, x, y)
+ { return x._value == y._value; }
+
+ /**
+ * Returns true if the two generators will produce different
+ * sequences of outputs.
+ */
+ BOOST_RANDOM_DETAIL_INEQUALITY_OPERATOR(inversive_congruential_engine)
- friend bool operator==(inversive_congruential x, inversive_congruential y)
- { return x.value == y.value; }
- friend bool operator!=(inversive_congruential x, inversive_congruential y)
- { return !(x == y); }
-#else
- // Use a member function; Streamable concept not supported.
- bool operator==(inversive_congruential rhs) const
- { return value == rhs.value; }
- bool operator!=(inversive_congruential rhs) const
- { return !(*this == rhs); }
-#endif
private:
- IntType value;
+ IntType _value;
};
#ifndef BOOST_NO_INCLASS_MEMBER_INITIALIZATION
// A definition is required even for integral static constants
-template<class IntType, IntType a, IntType b, IntType p, IntType val>
-const bool inversive_congruential<IntType, a, b, p, val>::has_fixed_range;
-template<class IntType, IntType a, IntType b, IntType p, IntType val>
-const typename inversive_congruential<IntType, a, b, p, val>::result_type inversive_congruential<IntType, a, b, p, val>::min_value;
-template<class IntType, IntType a, IntType b, IntType p, IntType val>
-const typename inversive_congruential<IntType, a, b, p, val>::result_type inversive_congruential<IntType, a, b, p, val>::max_value;
-template<class IntType, IntType a, IntType b, IntType p, IntType val>
-const typename inversive_congruential<IntType, a, b, p, val>::result_type inversive_congruential<IntType, a, b, p, val>::multiplier;
-template<class IntType, IntType a, IntType b, IntType p, IntType val>
-const typename inversive_congruential<IntType, a, b, p, val>::result_type inversive_congruential<IntType, a, b, p, val>::increment;
-template<class IntType, IntType a, IntType b, IntType p, IntType val>
-const typename inversive_congruential<IntType, a, b, p, val>::result_type inversive_congruential<IntType, a, b, p, val>::modulus;
+template<class IntType, IntType a, IntType b, IntType p>
+const bool inversive_congruential_engine<IntType, a, b, p>::has_fixed_range;
+template<class IntType, IntType a, IntType b, IntType p>
+const typename inversive_congruential_engine<IntType, a, b, p>::result_type inversive_congruential_engine<IntType, a, b, p>::multiplier;
+template<class IntType, IntType a, IntType b, IntType p>
+const typename inversive_congruential_engine<IntType, a, b, p>::result_type inversive_congruential_engine<IntType, a, b, p>::increment;
+template<class IntType, IntType a, IntType b, IntType p>
+const typename inversive_congruential_engine<IntType, a, b, p>::result_type inversive_congruential_engine<IntType, a, b, p>::modulus;
+template<class IntType, IntType a, IntType b, IntType p>
+const typename inversive_congruential_engine<IntType, a, b, p>::result_type inversive_congruential_engine<IntType, a, b, p>::default_seed;
#endif
-} // namespace random
+/// \cond show_deprecated
+
+// provided for backwards compatibility
+template<class IntType, IntType a, IntType b, IntType p, IntType val = 0>
+class inversive_congruential : public inversive_congruential_engine<IntType, a, b, p>
+{
+ typedef inversive_congruential_engine<IntType, a, b, p> base_type;
+public:
+ inversive_congruential(IntType x0 = 1) : base_type(x0) {}
+ template<class It>
+ inversive_congruential(It& first, It last) : base_type(first, last) {}
+};
+
+/// \endcond
/**
* The specialization hellekalek1995 was suggested in
* (editors), 1995, pp. 255-262. ftp://random.mat.sbg.ac.at/pub/data/wsc95.ps
* @endblockquote
*/
-typedef random::inversive_congruential<int32_t, 9102, 2147483647-36884165,
- 2147483647, 0> hellekalek1995;
+typedef inversive_congruential_engine<uint32_t, 9102, 2147483647-36884165,
+ 2147483647> hellekalek1995;
+
+} // namespace random
+
+using random::hellekalek1995;
} // namespace boost
+#include <boost/random/detail/enable_warnings.hpp>
+
#endif // BOOST_RANDOM_INVERSIVE_CONGRUENTIAL_HPP
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