Misclassification Cost Matrix
The Misclassification Cost for each class can be placed into a matrix of size $C \times C$ where $C$ is the number of classes. In this matrix, a point $(a,b)$ has the value of $\lambda_{a,b}$. This means that the diagonal values in the matrix are always $0$.
$$ \begin{bmatrix} \lambda_{1,1} & \lambda_{1,2} \\\\lambda_{2,1} & \lambda_{2,2} \end{bmatrix} $$