pres.cost: Examine the cost of lower level designs in forward assembly...
In YiFengEDMS/simPM: SIMulation-based power analysis for Planned Missing designs

pres.cost returns the cost of PM designs obtained in the process of forward assembly. For example, the users may want to know the cost of the designs with fewer number of missing data patterns than the one obtained using forward assembly.

1	pres.cost(opt.pattern, costmx, max.mk, pc, pd, n, k, Time, Time.complete)

`costmx`	A numeric vector containing the unit cost of each observed variable that is yet to be measured (post the funding cut). The cost is assumed to be constant across subjects, but it is allowed to vary across variables and across waves.
`pc`	Numeric. Proportion of completers: the proportion of subjects that will participate in all of the following waves of data collection and provide complete data. This must be greater than 0.
`pd`	Numeric. The proportion of subjects that will not participate in any of the following waves of data collection (i.e., people who will drop from the longitudinal study). This value can be 0.
`n`	The total sample size as initially planned.
`k`	Numeric. The number of observed variables collected at each wave.
`Time`	Numeric. The total number of time points (or total number of waves of data collection).
`Time.complete`	Numeric. Number of waves of data collection that have been completed before the funding cut occurs.