[R3.3] Maxent 패키지를 활용한 다항식 로지스틱 회귀 분류

/*******************************************************************************************************************
-- Title : [R3.3] Maxent 패키지를 활용한 다항식 로지스틱 회귀 분류
-- Reference : https://cran.r-project.org/web/packages
-- Key word : maxent package 패키지 로지스틱 logistic regression maximum entropy classifier read.csv 
*******************************************************************************************************************/

-- Chart

-- R

# -- LOAD LIBRARY
install.packages('maxent')
library(maxent)
 
# -- READ THE DATA, PREPARE THE CORPUS, and CREATE THE MATRIX
data <- read.csv(system.file("data/NYTimes.csv.gz",package="maxent"))
View(data)
View(data$Title[1:150])
View(VectorSource(data$Title[1:150]))
 
corpus <- Corpus(VectorSource(data$Title[1:150]))
corpus
 
matrix <- DocumentTermMatrix(corpus)
matrix
 
# -- TRAIN USING SPARSEM REPRESENTATION
sparse <- as.compressed.matrix(matrix)
model <- maxent(sparse[1:100,],as.factor(data$Topic.Code)[1:100])
 
# -- A DIFFERENT EXAMPLE (taken from package e10711)
# -- CREATE DATA
x <- seq(0.1, 5, by = 0.05)
y <- log(x) + rnorm(x, sd = 0.2)
 
# -- ESTIMATE MODEL AND PREDICT INPUT VALUES
m <- maxent(x, y)
new <- predict(m, x)
 
# -- VISUALIZE
plot(x, y)
points(x, log(x), col = 2)
points(x, new[,1], col = 4)

-- PDF

maxent.pdf