| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // <random> |
| |
| // template <class UIntType, UIntType a, UIntType c, UIntType m> |
| // class linear_congruential_engine; |
| |
| // result_type operator()(); |
| |
| #include <random> |
| #include <cassert> |
| |
| #include "test_macros.h" |
| |
| int main(int, char**) |
| { |
| typedef unsigned long long T; |
| |
| // m might overflow, but the overflow is OK so it shouldn't use schrage's algorithm |
| typedef std::linear_congruential_engine<T, 25214903917ull, 1, (1ull<<48)> E1; |
| E1 e1; |
| // make sure the right algorithm was used |
| assert(e1() == 25214903918); |
| assert(e1() == 205774354444503); |
| assert(e1() == 158051849450892); |
| // make sure result is in bounds |
| assert(e1() < (1ull<<48)); |
| assert(e1() < (1ull<<48)); |
| assert(e1() < (1ull<<48)); |
| assert(e1() < (1ull<<48)); |
| assert(e1() < (1ull<<48)); |
| |
| // m might overflow. The overflow is not OK and result will be in bounds |
| // so we should use shrage's algorithm |
| typedef std::linear_congruential_engine<T, (1ull<<2), 0, (1ull<<63) + 1> E2; |
| E2 e2; |
| // make sure shrage's algorithm is used (it would be 0s otherwise) |
| assert(e2() == 4); |
| assert(e2() == 16); |
| assert(e2() == 64); |
| // make sure result is in bounds |
| assert(e2() < (1ull<<48) + 1); |
| assert(e2() < (1ull<<48) + 1); |
| assert(e2() < (1ull<<48) + 1); |
| assert(e2() < (1ull<<48) + 1); |
| assert(e2() < (1ull<<48) + 1); |
| |
| // m will not overflow so we should not use shrage's algorithm |
| typedef std::linear_congruential_engine<T, 1ull, 1, (1ull<<48)> E3; |
| E3 e3; |
| // make sure the correct algorithm was used |
| assert(e3() == 2); |
| assert(e3() == 3); |
| assert(e3() == 4); |
| // make sure result is in bounds |
| assert(e3() < (1ull<<48)); |
| assert(e3() < (1ull<<48)); |
| assert(e3() < (1ull<<48)); |
| assert(e3() < (1ull<<48)); |
| assert(e2() < (1ull<<48)); |
| |
| return 0; |
| } |