The most straightforward use of the warm start class is to restart the solver after modifying problem parameters. To start the computation from a given warm start when the problem data has not been modified, the tree manager simply traverses the tree and adds those nodes marked as candidates for processing to the node queue. Once the queue has been reformed, the algorithm is then able to pick up exactly where it left off. Code for using the resolve command was shown in Figure 3.2. The situation is more challenging if the user modifies problem data in between calls to the solver. We address this situation next.