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std::subtra...carry_engine(3) C++ Standard Libarystd::subtra...carry_engine(3) NAME std::subtract_with_carry_engine - std::subtract_with_carry_engine Synopsis Defined in header <random> template< class UIntType, (since C++11) std::size_t w, std::size_t s, std::size_t r > class subtract_with_carry_engine; Is a random number engine that uses subtract with carry algorithm. The state of a subtract_with_carry_engine consists of a sequence \(\small{\{ X_i\}(0 \le i <r)}\){X i} (0 i <r), every \(\small{X_i}\)X i is in interval \(\small{[0, 2^w)}\)[0, 2w ). Let all subscripts applied to sequence be taken modulo r, c be the carry value which is either 0 or 1. The state transition is performed as follows: * let \(\small{Y=X_{i-s}-X_{i-r}-c}\)Y=X i-s-X i-r-c, * set \(\small{X_i}\)X i to \(\small{Y \mod 2^w}\)Y mod 2w , * set c to 1, if \(\small{Y<0}\)Y<0, to 0 otherwise. The following typedefs define the random number engine with two com- monly used parameter sets: Defined in header <random> Type Definition ranlux24_base(C++11) std::subtract_with_carry_en- gine<std::uint_fast32_t, 24, 10, 24> ranlux48_base(C++11) std::subtract_with_carry_en- gine<std::uint_fast64_t, 48, 5, 12> Template parameters The result type generated by the generator. The effect is undefined if UIntType - this is not one of unsigned short, unsigned int, unsigned long, or unsigned long long. w - The word size, in bits, of the state sequence, 10 < w <= std::numeric_limits<UIntType>::digits. s - The short lag. r - The long lag, where 0 < s < r. Member types Member type Definition result_type (C++11) The integral type generated by the engine. Re- sults are undefined if this is not an unsigned integral type. Member functions Construction and Seeding constructor constructs the engine (C++11) (public member function) seed sets the current state of the engine (C++11) (public member function) Generation operator() advances the engine's state and returns the gener- ated value (C++11) (public member function) discard advances the engine's state by a specified amount (C++11) (public member function) Characteristics min gets the smallest possible value in the output range [static] (C++11) (public static member function) max gets the largest possible value in the output range [static] (C++11) (public static member function) Non-member functions operator== compares the internal states of two pseudo-random number operator!= engines (C++11) (function) (C++11)(removed in C++20) operator<< performs stream input and output on pseudo-random number operator>> engine (C++11) (function template) Member constants constexpr size_t word_size template parameter w, the word size [static] (C++11) (public static member constant) constexpr size_t short_lag template parameter s, the short lag [static] (C++11) (public static member constant) constexpr size_t long_lag template parameter r, the long lag [static] (C++11) (public static member constant) constexpr UIntType default_seed constant value 19780503u [static] (C++11) (public static member constant) http://cppreference.com 2022.07.31 std::subtra...carry_engine(3)
NAME | Synopsis | Template parameters | Member types | Member functions | Construction and Seeding | Generation | Characteristics | Non-member functions | Member constants
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