n_features: Extract the number of features used in a Maxent model

In johnbaums/rmaxent: Tools for working with Maxent in R

Extract the number of features used in a Maxent model

Description

Calculate the number of non-zero features used in a Maxent model.

Usage

n_features(lambdas)

Arguments

lambdas

A vector of one or more file paths to Maxent .lambdas files, or a list of one or more MaxEnt fitted model objects.

Value

An vector with one element for each element of lambdas.

Examples

# Below we use the dismo::maxent example to fit a Maxent model:
if (require(dismo) && require(rJava) && 
    file.exists(system.file('java/maxent.jar', package='dismo'))) {
  fnames <- list.files(system.file('ex', package='dismo'), '\\.grd$', 
                       full.names=TRUE )
  predictors <- stack(fnames)
  occurrence <- system.file('ex/bradypus.csv', package='dismo')
  occ <- read.table(occurrence, header=TRUE, sep=',')[,-1]
  me <- maxent(predictors, occ, args=c('hinge=false', 'threshold=false'),
               path=file.path(tempdir(), 'ex1'))
  n_features(me)
  
  # comparing multiple models
  me2 <- maxent(predictors, occ, args=c('betamultiplier=3'), 
                path=file.path(tempdir(), 'ex2'))
  n_features(list(me, me2))
  
  # or use lambdas files
  ff <- file.path(tempdir(), c('ex1', 'ex2'), 'species.lambdas')
  ff
  n_features(ff)
}

johnbaums/rmaxent documentation built on Oct. 11, 2024, 11:14 a.m.