of a two-column matrix of counts, sometimes referred to as grouped data. We discuss this in more detail in Section 4.2.The Newton algorithm is not guaranteed to converge without step-size optimization [in Lee et al., 2006]. Our code does not implement any checks for divergence; this would slow it down, and when used as recommended we do not feel it is necessary.. We have a closed form expression for the starting solutions, and each subsequent solution is warm-started from the previous close-by solution, which generally makes the quadratic approximations very accurate. We have not encountered any divergence problems so far.
