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sdrangel/plugins/channelrx/demoddatv/ldpctool/exclusive_reduce.h

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2.0 KiB
C++

///////////////////////////////////////////////////////////////////////////////////////
// Copyright (C) 2021 Edouard Griffiths, F4EXB <f4exb06@gmail.com> //
// //
// This program is free software; you can redistribute it and/or modify //
// it under the terms of the GNU General Public License as published by //
// the Free Software Foundation as version 3 of the License, or //
// (at your option) any later version. //
// //
// This program is distributed in the hope that it will be useful, //
// but WITHOUT ANY WARRANTY; without even the implied warranty of //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the //
// GNU General Public License V3 for more details. //
// //
// You should have received a copy of the GNU General Public License //
// along with this program. If not, see <http://www.gnu.org/licenses/>. //
///////////////////////////////////////////////////////////////////////////////////////
/*
Reduce N times while excluding ith input element
Copyright 2018 Ahmet Inan <inan@aicodix.de>
*/
#ifndef EXCLUSIVE_REDUCE_HH
#define EXCLUSIVE_REDUCE_HH
namespace ldpctool {
namespace CODE {
template <typename TYPE, typename OPERATOR>
void exclusive_reduce(const TYPE *in, TYPE *out, int N, OPERATOR op)
{
TYPE pre = in[0];
for (int i = 1; i < N-1; ++i) {
out[i] = pre;
pre = op(pre, in[i]);
}
out[N-1] = pre;
TYPE suf = in[N-1];
for (int i = N-2; i > 0; --i) {
out[i] = op(out[i], suf);
suf = op(suf, in[i]);
}
out[0] = suf;
}
} // namespace CODE
} // namespace ldpctool
#endif