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:
label
Name of account account to evaluate sustainable yield
initialValue
Initial value for minimum yield target level (first search iteration) (double expected sustainable yield level)
stepFactor
Relative amount by which to increment/decrement target level
tolerance1
tolerance for sustainability evaluation (maximum value of maximum deviation)
tolerance2
tolerance for sustainability evaluation (maximum value of mean deviation)
startPeriod
first period in sustainablility interval
endPeriod
last period in sustainability interval
searchIters
number of scheduler iterations to wait between stability samples
testIters
number of stability samples to store
stabilityThreshhold
controls sensitivity to solution improvement for for stability calculations (smaller threshhold = more sensitive = longer convergence times)
initDeltaFactor
controls target level for second search iteration (eg. 0.5 = 1.5 * mean account value)
deltaFactorFactor
controls change in target level for third and subsequent search iterations
levelFactor
controls 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:
searchIters
1000
testIters
10
stabilityThreshhold
0.01f
initDeltaFactor
0.5f
deltaFactorFactor
0.5f
levelFactor
0.01f
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.