logistic_exponential: logistic-exponential function logistic-exponential...

In nikolaifish/bamExtras: Functions and Data in Support of Stock Assessments with the Beaufort Assessment Model (BAM)

logistic-exponential function logistic-exponential selectivity function. The function has 4 parameters. When fitting in bam, one of the parameters should be fixed. Note that if the minimim value of ages is equal to the value of joint, then A50 and slope have no effect on the result.

Description

logistic-exponential function logistic-exponential selectivity function. The function has 4 parameters. When fitting in bam, one of the parameters should be fixed. Note that if the minimim value of ages is equal to the value of joint, then A50 and slope have no effect on the result.

Usage

logistic_exponential(ages, A50, slope, sigma, joint)

Arguments

ages	vector of ages
A50	age at 50% selection (ascending limb)
slope	rate of increase
sigma	controls rate of descent (descending limb)
joint	age to join curves

Author(s)

Erik Williams, Kyle Shertzer, and Nikolai Klibansky

Examples

rdat <- rdat_GrayTriggerfish
fp <- rdat$parm.cons[8,grepl("rHB\\.D$",names(rdat$parm.cons))]
logistic_exponential(ages=rdat$a.series$age,
A50 = fp$selpar.L50.rHB.D,
slope = fp$selpar.slope.rHB.D,
sigma = fp$selpar.sigma.rHB.D,
joint = fp$selpar.afull.rHB.D)

nikolaifish/bamExtras documentation built on April 17, 2025, 9:44 p.m.