When FUSE generates a structure, either randomly or through one of the actions listed below, it will "error check" the proposed new structure for the co-ordination chemistry of all of the cationanion environments. If greater than 25% of the cations are found to have an incorrect coordination, FUSE will not accept the random structure and will repeat the process starting from the action selection. Note: this error checking procedure can then often result in the actual percentage of each action (see below) selected when running the MC search deviating away from that set in the input file by any fixed policy making it difficult to ensure a uniform probability distribution among actions.