In logitr: Logit Models w/Preference & WTP Space Utility Parameterizations

\begin{equation} P_{jc} = \frac{ \mathrm{exp} \left[ \lambda\left(\betaVec' \xVec_{j} - p_{j}\right) \right] } { \sum\limits_{k \in \mathcal{J}c}\mathrm{exp} \left[ \lambda\left(\betaVec' \xVec{k} - p_{k}\right) \right] }, \quad\quad \forall c \in \left {1,2,3,\dots C \right }, \quad j \in \mathcal{J}_c, \label{eq:WTPlogitProbability} \end{equation}