pattern_lookup()

MAYAFLUX_API double MayaFlux::Kinesis::Discrete::pattern_lookup ( std::span< const double >  window, std::span< const double >  coefs  )

noexcept

Table indexed by the recent shape of the window.

coefs: [levels, count, lo, hi, table...]. The newest count values are each quantised to one of levels cells over [lo, hi] (Lattice1D), combined into an index with the newest value as the lowest digit, and the table of levels^count entries is read there. Values outside [lo, hi] fall in the edge cells and missing values count as zero. A table too small for the index range, or hi not above lo, gives zero.

Definition at line 341 of file Kernels.cpp.

{
    if (coefs.size() < 5 || !(coefs[3] > coefs[2]))
        return 0.0;
 
    const auto levels = static_cast<uint32_t>(std::max(coefs[0], 1.0));
    const auto count = static_cast<size_t>(std::max(coefs[1], 1.0));
    const auto table = coefs.subspan(4);
 
    size_t total = 1;
    for (size_t i = 0; i < count; ++i) {
        if (total > table.size() / levels)
            return 0.0;
        total *= levels;
    }
 
    const Lattice1D lattice { .resolution = levels, .bounds = { .min = coefs[2], .max = coefs[3] } };
 
    size_t index = 0;
    size_t stride = 1;
    for (size_t i = 0; i < count; ++i) {
        const double value = i < window.size() ? window[i] : 0.0;
        index += static_cast<size_t>(lattice.cell_at(value)) * stride;
        stride *= levels;
    }
    return table[index];
}

References count, index, MayaFlux::Kinesis::Lattice1D::resolution, total, value, and window.