Prepare for CRAN (#4)

* Update

* Update

* Refix

.Rbuildignore

@@ -1,3 +1,6 @@
-^cran-comments\.md$
 ^.*\.Rproj$
 ^\.Rproj\.user$
+^README\.Rmd$
+^\.travis\.yml$
+^cran-comments\.md$
+^docs$

DESCRIPTION

@@ -1,13 +1,13 @@
 Package: frequentdirections
 Type: Package
-Title: Implementation of Frequent-Directions algorithm for efficient matrix sketching [E. Liberty, SIGKDD2013]
+Title: Implementation of Frequent-Directions Algorithm for Efficient Matrix Sketching
 Version: 0.1.0
 Authors@R: c(
   person("Shinichi", "Takayanagi", , "shinichi.takayanagi@gmail.com", role = c("aut", "cre")),
   person("Nagi", "Teramo", , "teramonagi@gmail.com", role = c("aut"))
   )
-Description: Implementation of Frequent-Directions algorithm 
-  for efficient matrix sketching [E. Liberty, SIGKDD2013]
+Description: Implement frequent-directions algorithm for efficient matrix sketching. 
+  (Edo Liberty (2013) <doi:10.1145/2487575.2487623>).
 URL: https://github.com/shinichi-takayanagi/frequentdirections
 BugReports: https://github.com/shinichi-takayanagi/frequentdirections/issues
 License: MIT + file LICENSE

R/frequentdirections.R

@@ -9,6 +9,7 @@ all_zero_row_index <- function(x, eps){
 #' @param a Original matrix to be sketched (n x m)
 #' @param l The number of rows in sketched matrix (l x m)
 #' @param eps If a value is smaller than eps, that is considered as equal to zero. The default value is 10^(-8)
+#' @example inst/examples/example.R
 #' @export
 sketching <- function(a, l, eps=10^(-8)){
   m <- ncol(a)
@@ -44,6 +45,7 @@ sketching <- function(a, l, eps=10^(-8)){
 #' @param a Original matrix to be sketched (n x m)
 #' @param label Group index for each a's row. These values are used for group and color.
 #' @param b A sketched matrix (l x m)
+#' @example inst/examples/example.R
 #' @export
 plot_svd <- function(a, label = NULL, b = a){
   v <- svd(b)$v
@@ -53,7 +55,7 @@ plot_svd <- function(a, label = NULL, b = a){
   # Projection matrix(x_p = XV = UΣ) and plot
   x <- a %*% v[,1:2]
   df <- data.frame(x = x[,1], y = x[,2])
-  ggobj <- ggplot2::ggplot(df, ggplot2::aes(x=x, y=y)) +
+  ggobj <- ggplot2::ggplot(df, ggplot2::aes_string(x="x", y="y")) +
     ggplot2::labs(x = "The first singular vector", y = "The second singular vector")
   ggobj + if(!is.null(label)){
     label <- as.character(label)

inst/examples/example.R

@@ -0,0 +1,16 @@
+# Dummy data
+size_col <- 50
+size_row <- 10^3
+x <- matrix(
+  c(rnorm(size_row * size_col), rnorm(size_row * size_col, mean=1)),
+  ncol = size_col, byrow = TRUE
+)
+x <- scale(x)
+y <- rep(1:2, each=size_row)
+# Show 2D plot using SVD
+frequentdirections::plot_svd(x, y)
+# Matrix Skethinc(l=6)
+b <- frequentdirections::sketching(x, 6, 10^(-8))
+# Show 2D plot using sketched matrix and show similar result with the above
+# That means that 6 dim is enough to express the original data matrix (x)
+frequentdirections::plot_svd(x, y, b)