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

35 lines
604 B
C++

/*
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