Name

maximizeSustainableYield — This method implements a binary-search sustainable harvest level calculator, written by Greg Paradis.

Overview

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.

Syntax

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

Description

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.

Syntax

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

Description

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.