DET (version 2.0.2)

detc: DET Curve calculation

Description

From a dataframe of responses and predictors, the function calculates and plots the DET curves for each pair (response,predictor). In addition, ROC curves can be displayed by activating a boolean argument.

Usage

detc(responses, predictors, names = c(""), positive = "", title = "",
  legend = "topright", file, plotROC = FALSE, xlim = c(0.05, 50),
  ylim = c(0.05, 50), col = c("black", "blue", "red", "green",
  "yellow"))

Arguments

responses

A dataframe of factor, numeric or character vector of responses, typically encoded with 0 (non-target) and 1 (target). By default, the first two values of levels(as.factor(response)) are taken. If only one response is passed, it will be used for calculating all the curves.

predictors

A dataframe of numeric vector of the same length than response, containing the predicted value of each observation. An ordered factor is coerced to a numeric.

names

Array of strings, containing the name of each pair (response,predictor) that will appear in the legend of the graph.

positive

string with the name of the 'positive' class. Default: negative class will be the first string of response levels and positive class the second string.

title

Main tile for the graph

legend

the location of the leyend in the graph. Could be a single keyword from the list "bottomright", "bottom", "bottomleft", "left", "topleft", "top", "topright", "right", "center" and NULL. Default: "topright".

file

The name of the file where the plot will be saved. If Empty, the DET and ROC curves are plotted by the graphic output.

plotROC

Boolean specifying ploting or not the ROC Curve

xlim

numeric vector of length 2, giving the x coordinates range.

ylim

numeric vector of length 2, giving the y coordinates range.

col

Array indicating a specification for the plotting color for DET curve of each classifier.

Value

A list of dataframe, one per classifier. Each dataframe contains the name of the classifier, and the parameters of the DET curve (FPR, FNR and the thresholds used), along with the Equal Error Rate.

Examples

# NOT RUN {
n <- 5000
set.seed(12345)
#Predictors with normal distribution
set.seed(1235)
scoreNegative <- rnorm(n, mean = 0.25,sd = 0.125) 
set.seed(11452)
scorePositive1 <- rnorm(n, mean = 0.55,sd = 0.125)
set.seed(54321)
scorePositive2 <- rnorm(n, mean = 0.65,sd = 0.125)
set.seed(65987)
scorePositive3 <- rnorm(n, mean = 0.75,sd = 0.125) 
response = c(rep(c("target"), times = n),rep(c("nontarget"), times = n))
predictor1 = c(scoreNegative,scorePositive1)
predictor2 = c(scoreNegative,scorePositive2)
predictor3 = c(scoreNegative,scorePositive3)
responses <- data.frame(
  response = response
)
predictors <- data.frame(
  DET1 = predictor1,
  DET2 = predictor2,
  DET3 = predictor3
)
#We can also plot the ROC curves activating logical attribute 'plotROC'
detcurve <- detc(responses,predictors,
                names = names(predictors),
                positive="target",
                title="Example",
                plotROC = TRUE)
                
#If you want to plot the EER and its CI on the curves:
for (name in names(detcurve)){
    points(qnorm(detcurve[[name]]$EER),qnorm(detcurve[[name]]$EER),
           pch=19,col = detcurve[[name]]$color,lwd=3)
}
     

# }