IPMpack (version 2.1)

growth: Estimates growth probabilities.

Description

Generic function to predict the pdf (probability density function) of continuous (e.g. size) stage at t+1 given stage at t and a growth object.

Usage

growth(size, sizeNext, cov, growthObj)

Arguments

size

vector of current sizes.

sizeNext

vector of sizes in the next time-step.

cov

a data-frame with one row containing all covariates for this time-step.

growthObj

a growth object.

Value

a vector of length sizeNext giving the pdf (probability density function) of each value of sizeNext.

Details

Models defining continuous (size) stage at t+1, or growth increment, or log growth increment are defined; with various underlying statistical models allowing decreasing variance in size, etc.

References

Easterling, Ellner & Dixon. 2000. Size-specific sensitivity: a new structured population model. Ecology 81, p694-708.

See Also

surv, growSurv

Examples

dff <- generateData()
gr1 <- makeGrowthObj(dff)
sizeRange <- c(1:20)
sizeInit <- 1
growth(sizeInit, sizeRange, data.frame(cov=1), gr1)
plot(growth(sizeInit, sizeRange, data.frame(cov=1), gr1), type="l", 
	col = "dark gray", xlab = "Continuous (e.g. size) stage at time t+1", 
	ylab = paste("Probability of growth to a specific size in t+1 from size ", 
			sizeInit, " at time t"))