Method get_trellis

src/Module/Encoder/Conv/Encoder_conv.cpp:162–200

template<typename B>
std::vector<std::vector<int>>
Encoder_conv<B>::get_trellis()
{
    std::vector<std::vector<int>> trellis(10, std::vector<int>(n_states));

    // Fill trellis[0..5] for BCJR compatibility (same convention as RSC encoder)
    std::vector<bool> occurrence(n_states, false);

    for (int i = 0; i < n_states; i++)
    {
        // input = 0
        int next0 = next_state_table[2 * i + 0];
        int out0 = output_table[2 * i + 0];

        trellis[0 + (occurrence[next0] ? 3 : 0)][next0] = i;    // initial state
        trellis[1 + (occurrence[next0] ? 3 : 0)][next0] = +1;   // gamma coeff
        trellis[2 + (occurrence[next0] ? 3 : 0)][next0] = out0; // gamma (packed output)

        trellis[6][i] = next0; // next state, input = 0
        trellis[7][i] = out0;  // packed output, input = 0

        occurrence[next0] = true;

        // input = 1
        int next1 = next_state_table[2 * i + 1];
        int out1 = output_table[2 * i + 1];

        trellis[0 + (occurrence[next1] ? 3 : 0)][next1] = i;    // initial state
        trellis[1 + (occurrence[next1] ? 3 : 0)][next1] = -1;   // gamma coeff
        trellis[2 + (occurrence[next1] ? 3 : 0)][next1] = out1; // gamma (packed output)

        trellis[8][i] = next1; // next state, input = 1
        trellis[9][i] = out1;  // packed output, input = 1

        occurrence[next1] = true;
    }

    return trellis;
}

// ==================================================================================== explicit template instantiation
#include "Tools/types.h"