predict.inclass: Predictions from an Inclass Object

In ipred: Improved Predictors

Predictions from an Inclass Object

Description

Predicts the class membership of new observations through indirect classification.

Usage

## S3 method for class 'inclass'
predict(object, newdata, ...)

Arguments

object	object of class inclass, see inclass.
newdata	data frame to be classified.
...	additional arguments corresponding to the predictive models specified in inclass.

Details

Predictions of class memberships are calculated. i.e. values of the intermediate variables are predicted and classified following cFUN, see inclass.

Value

The vector of predicted classes is returned.

References

David J. Hand, Hua Gui Li, Niall M. Adams (2001), Supervised classification with structured class definitions. Computational Statistics & Data Analysis 36, 209–225.

Andrea Peters, Berthold Lausen, Georg Michelson and Olaf Gefeller (2003), Diagnosis of glaucoma by indirect classifiers. Methods of Information in Medicine 1, 99-103.

See Also

inclass

Examples

## Not run: 
# Simulation model, classification rule following Hand et al. (2001)

theta90 <- varset(N = 1000, sigma = 0.1, theta = 90, threshold = 0)

dataset <- as.data.frame(cbind(theta90$explanatory, theta90$intermediate))
names(dataset) <- c(colnames(theta90$explanatory),
colnames(theta90$intermediate))

classify <- function(Y, threshold = 0) {
  Y <- Y[,c("y1", "y2")]
  z <- (Y > threshold)
  resp <- as.factor(ifelse((z[,1] + z[,2]) > 1, 1, 0))
  return(resp)
}

formula <- response~y1+y2~x1+x2

fit <- inclass(formula, data = dataset, pFUN = list(list(model = lm)), 
 cFUN = classify)

predict(object = fit, newdata = dataset)


data("Smoking", package = "ipred")

# explanatory variables are: TarY, NicY, COY, Sex, Age
# intermediate variables are: TVPS, BPNL, COHB
# reponse is defined by:

classify <- function(data){
  data <- data[,c("TVPS", "BPNL", "COHB")]
  res <- t(t(data) > c(4438, 232.5, 58))
  res <- as.factor(ifelse(apply(res, 1, sum) > 2, 1, 0))
  res
}

response <- classify(Smoking[ ,c("TVPS", "BPNL", "COHB")])
smoking <- cbind(Smoking, response)

formula <- response~TVPS+BPNL+COHB~TarY+NicY+COY+Sex+Age

fit <- inclass(formula, data = smoking, 
  pFUN = list(list(model = lm)), cFUN = classify)


predict(object = fit, newdata = smoking)

## End(Not run)

data("GlaucomaMVF", package = "ipred")
library("rpart")
glaucoma <- GlaucomaMVF[,(names(GlaucomaMVF) != "tension")]
# explanatory variables are derived by laser scanning image and intra occular pressure
# intermediate variables are: clv, cs, lora
# response is defined by

classify <- function (data) {
  attach(data) 
  res <- ifelse((!is.na(clv) & !is.na(lora) & clv >= 5.1 & lora >= 
        49.23372) | (!is.na(clv) & !is.na(lora) & !is.na(cs) & 
        clv < 5.1 & lora >= 58.55409 & cs < 1.405) | (is.na(clv) & 
        !is.na(lora) & !is.na(cs) & lora >= 58.55409 & cs < 1.405) | 
        (!is.na(clv) & is.na(lora) & cs < 1.405), 0, 1)
  detach(data)
  factor (res, labels = c("glaucoma", "normal"))
}

fit <- inclass(Class~clv+lora+cs~., data = glaucoma, 
             pFUN = list(list(model = rpart)), cFUN = classify)

data("GlaucomaM", package = "TH.data")
predict(object = fit, newdata = GlaucomaM)

ipred documentation built on July 18, 2024, 3 p.m.