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construct/include/ircd/math/mean.h

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1.5 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2021 Jason Volk <jason@zemos.net>
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice is present in all copies. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_MATH_MEAN_H
namespace ircd::math
{
template<class T,
class R = T>
typename std::enable_if<!simd::is<T>(), R>::type
mean(const vector_view<const T>);
template<class T,
class R = T>
typename std::enable_if<simd::is<T>(), simd::lane_type<R>>::type
mean(const vector_view<const T>);
}
namespace ircd
{
using math::mean;
}
template<class T,
class R>
inline typename std::enable_if<ircd::simd::is<T>(), ircd::simd::lane_type<R>>::type
ircd::math::mean(const vector_view<const T> a)
{
R acc {0};
simd::for_each(a.data(), u64x2{0, a.size()}, [&acc]
(const auto block, const auto mask)
{
const R dp
(
simd::lane_cast<R>(block)
);
acc += dp;
});
auto num(acc[0]);
for(uint i(1); i < simd::lanes<T>(); ++i)
num += acc[i];
const auto den
{
a.size() * simd::lanes<T>()
};
num /= den;
return num;
}
template<class T,
class R>
inline typename std::enable_if<!ircd::simd::is<T>(), R>::type
ircd::math::mean(const vector_view<const T> a)
{
R ret{0};
size_t i{0};
while(i < a.size())
ret += a[i++];
ret /= i;
return ret;
}