This page describes the options you can set to control the behaviour of the speed
package, especially technical options in the speed() function controlling the
behaviour of the optimisation algorithm.
Details
speed.swap_countNumber of treatment swaps per iteration (default: 1).
speed.swap_all_blocksLogical; if
TRUE, performs swaps in all blocks at each iteration (default:FALSE).speed.adaptive_swapsLogical; if
TRUE, adjusts swap parameters based on temperature (default:FALSE).speed.start_tempStarting temperature for simulated annealing (default: 100). A higher start temperature allows the algorithm to accept worse solutions early on, encouraging exploration of the solution space and helping to avoid local optima. Lower values make the algorithm greedier from the start, which can speed up convergence but increases the risk of getting stuck in a poor solution. A good starting temperature allows moderately worse solutions to be accepted with a probability of 70–90% at the beginning of the optimisation.
speed.cooling_rateRate at which temperature decreases for simulated annealing (default: 0.99). This controls how quickly the algorithm shifts from exploration to exploitation. The temperature is updated at each iteration by multiplying it by this rate:
T_i = start_temp * cooling_rate^i. A higher cooling rate (e.g. 0.995–0.999) results in slower cooling and a longer exploration phase, which is generally better for complex or noisy optimisation landscapes. Lower values (e.g. 0.95–0.98) cool quickly, leading to faster convergence but greater risk of premature convergence to a suboptimal design.speed.random_initialisationLogical; if TRUE, randomly shuffle items within
swap_within(default: FALSE)speed.adj_weightWeight for adjacency score (default: 0).
speed.bal_weightWeight for balance score (default: 1).
Setting options
You can set these options using base::options(), either at the start of a session
or within your code:
options(speed.swap_count = 5, speed.swap_all_blocks = TRUE)