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/*
* Copyright 2008-2013 NVIDIA Corporation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <thrust/detail/config.h>
#if defined(_CCCL_IMPLICIT_SYSTEM_HEADER_GCC)
# pragma GCC system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_CLANG)
# pragma clang system_header
#elif defined(_CCCL_IMPLICIT_SYSTEM_HEADER_MSVC)
# pragma system_header
#endif // no system header
THRUST_NAMESPACE_BEGIN
namespace random
{
namespace detail
{
template<typename T, T a, T c, T m, bool = (m == 0)>
struct static_mod
{
static const T q = m / a;
static const T r = m % a;
__host__ __device__
T operator()(T x) const
{
THRUST_IF_CONSTEXPR(a == 1)
{
x %= m;
}
else
{
T t1 = a * (x % q);
T t2 = r * (x / q);
if(t1 >= t2)
{
x = t1 - t2;
}
else
{
x = m - t2 + t1;
}
}
THRUST_IF_CONSTEXPR(c != 0)
{
const T d = m - x;
if(d > c)
{
x += c;
}
else
{
x = c - d;
}
}
return x;
}
}; // end static_mod
// Rely on machine overflow handling
template<typename T, T a, T c, T m>
struct static_mod<T,a,c,m,true>
{
__host__ __device__
T operator()(T x) const
{
return a * x + c;
}
}; // end static_mod
template<typename T, T a, T c, T m>
__host__ __device__
T mod(T x)
{
static_mod<T,a,c,m> f;
return f(x);
} // end static_mod
} // end detail
} // end random
THRUST_NAMESPACE_END
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