maximizeSustainableYield — This method implements a binary-search sustainable harvest level calculator, written by Greg Paradis.
This method implements a binary-search sustainable harvest level calculator, written by Greg Paradis. The calculator works by iteratively adjusting targets and running the simulator until convergence is reached on the parameters.
void maximizeSustainableYield ( String label , int initialValue , float tolerance1 , float tolerance2 , int startPeriod , int endPeriod , int searchIters , int testIters , float stabilityThreshhold , float initDeltaFactor , float deltaFactorFactor , float levelFactor )
The command has the following arguments:
labelName of account account to evaluate sustainable yield
initialValueInitial value for minimum yield target level (first search iteration) (double expected sustainable yield level)
stepFactorRelative amount by which to increment/decrement target level
tolerance1tolerance for sustainability evaluation (maximum value of maximum deviation)
tolerance2tolerance for sustainability evaluation (maximum value of mean deviation)
startPeriodfirst period in sustainablility interval
endPeriodlast period in sustainability interval
searchItersnumber of scheduler iterations to wait between stability samples
testItersnumber of stability samples to store
stabilityThreshholdcontrols sensitivity to solution improvement for for stability calculations (smaller threshhold = more sensitive = longer convergence times)
initDeltaFactorcontrols target level for second search iteration (eg. 0.5 = 1.5 * mean account value)
deltaFactorFactorcontrols change in target level for third and subsequent search iterations
levelFactorcontrols size of gap between minimum and maximum target levels
Maximize sustainable harvest level. Starts by running scheduler with minimum yield target set to value specified in initialValue parameter till solution stabilizes and stops scheduler. Minimum yield target is then set to mean harvest level, and scheduler is restarted and solution is allowed to stabilize. If minimum yield target is sustainable (use tolerance parameter to evaluate sustainability), increment minimum yield target level by relative amount specified in step parameter, else decrement minimum yield target level by relative amount specified in step parameter. Repeat till maximum sustainable yield found. Stop scheduler and save scenario.
void maximizeSustainableYield ( String label , int initialValue , int tolerance1 , int tolerance2 , int startPeriod , int endPeriod )
The command has the following arguments:
searchIters1000
testIters10
stabilityThreshhold0.01f
initDeltaFactor0.5f
deltaFactorFactor0.5f
levelFactor0.01f
Invoke the maximiseSustainableYield method with standard search parameters. See the documentation of the previous method for a parameter description. The following only describes the default settings that are used.