Figure 2.

An example demonstrating that k-shortest path cannot be used to find paths with minimal-switching. The nodes represent reactions and are annotated with species in which the reaction exist. The path on the left requires species p1 and the path on the right requires speices p3. Reaction nodes 3 and 4 are shared between the two paths. The path on the left incurrs a switch and the path on the right incurrs no switch. The switching requirement cannot be captured using edge weights assigned to the edge 3,4. Instead, the score of each paths should be computed separately.