inline Float miWeight(Float pdfA, Float pdfB) const {
    pdfA *= pdfA;
    pdfB *= pdfB;
    return pdfA / (pdfA + pdfB);
}

static inline float powerHeuristic(float pdf0, float pdf1)
{
    return (pdf0*pdf0)/(pdf0*pdf0 + pdf1*pdf1);
}