diff options
Diffstat (limited to 'libcxx')
| -rw-r--r-- | libcxx/include/random | 4 | ||||
| -rw-r--r-- | libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq_all_zero.pass.cpp | 81 |
2 files changed, 83 insertions, 2 deletions
diff --git a/libcxx/include/random b/libcxx/include/random index 89664a6ca33..724bd0fc215 100644 --- a/libcxx/include/random +++ b/libcxx/include/random @@ -2337,7 +2337,7 @@ mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, for (size_t __i = 1; __i < __n; ++__i) if (__x_[__i] != 0) return; - __x_[0] = _Max; + __x_[0] = result_type(1) << (__w - 1); } } @@ -2363,7 +2363,7 @@ mersenne_twister_engine<_UIntType, __w, __n, __m, __r, __a, __u, __d, __s, __b, for (size_t __i = 1; __i < __n; ++__i) if (__x_[__i] != 0) return; - __x_[0] = _Max; + __x_[0] = result_type(1) << (__w - 1); } } diff --git a/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq_all_zero.pass.cpp b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq_all_zero.pass.cpp new file mode 100644 index 00000000000..4599348f4a0 --- /dev/null +++ b/libcxx/test/std/numerics/rand/rand.eng/rand.eng.mers/ctor_sseq_all_zero.pass.cpp @@ -0,0 +1,81 @@ +//===----------------------------------------------------------------------===// +// +// The LLVM Compiler Infrastructure +// +// This file is dual licensed under the MIT and the University of Illinois Open +// Source Licenses. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +// <random> + +// template <class UIntType, size_t w, size_t n, size_t m, size_t r, +// UIntType a, size_t u, UIntType d, size_t s, +// UIntType b, size_t t, +// UIntType c, size_t l, UIntType f> +// class mersenne_twister_engine; + +// template <class Sseq> explicit mersenne_twister_engine(Sseq &q); +// +// [ ... ] Finally, if the most significant $w-r$ bits of $X_{-n}$ are zero, +// and if each of the other resulting $X_i$ is $0$, changes $X_{-n}$ to +// $ 2^{w-1} $. + +#include <random> + +#include <algorithm> +#include <cassert> +#include <cstddef> +#if TEST_STD_VER >= 11 +#include <initializer_list> +#endif + +struct all_zero_seed_seq { + typedef unsigned int result_type; + + all_zero_seed_seq() {} + + template <typename InputIterator> + all_zero_seed_seq(InputIterator, InputIterator) {} +#if TEST_STD_VER >= 11 + all_zero_seed_seq(std::initializer_list<result_type>) {} +#endif + + template <typename RandomAccessIterator> + void generate(RandomAccessIterator rb, RandomAccessIterator re) { + std::fill(rb, re, 0u); + } + + std::size_t size() const { return 0u; } + template <typename OutputIterator> void param(OutputIterator) const {} +}; + +template <typename result_type, std::size_t word_size> +void test(void) { + const std::size_t state_size = 1u; + const std::size_t shift_size = 1u; + const std::size_t tempering_l = word_size; + + all_zero_seed_seq q; + std::mersenne_twister_engine<result_type, word_size, state_size, + shift_size, + 0u, + 0x0, + 0u, 0x0, 0u, 0x0, 0u, 0x0, + tempering_l, + 0u> + e(q); + + const result_type Xneg1 = result_type(1) << (word_size - 1); + const result_type Y = Xneg1; + const result_type X0 = Xneg1 ^ (Y >> 1); + assert(e() == X0); +} + +int main() { + // Test for k == 1: word_size <= 32. + test<unsigned short, 3u>(); + + // Test for k == 2: (32 < word_size <= 64). + test<unsigned long long, 33u>(); +} |
