Added function to mean-center the data

2 files changed, 71 insertions, 1 deletions

diff --git a/R/demean.R b/R/demean.R
new file mode 100644
index 0000000..9f1f436
--- /dev/null
+++ b/R/demean.R
@@ -0,0 +1,70 @@
+#' Mean-Center the data
+#' 
+#' Mean Centers the input and output matrices. 
+#' 
+#' @param data an object of class \code{idframe}
+#' 
+#' @return 
+#' A list containing the following elements
+#' 
+#' \tabular{ll}{
+#'    \code{fitted.values} \tab \code{idframe} object with mean-centered variables \cr
+#'    \code{output.mean} \tab \code{vector} containing means for each output variable \cr
+#'    \code{input.mean} \tab \code{vector} containing trend fits for each input variable
+#'  }
+#' 
+#' @examples
+#' data(cstr)
+#' fit <- detrend.idframe(cstr)
+#' cstr_detrend <- predict(fit) 
+#' 
+#' @seealso \code{\link{predict.demean}}, \code{\link[stats]{colMeans}}
+#' @export
+demean <- function(data){
+  
+  data_demean <- data 
+  output.mean <- colMeans(data$output)
+  input.mean <- colMeans(data$input)
+  
+  
+  data_demean$output <- data$output - output.mean
+  data_demean$input <- data$input - input
+  
+  est <- list(fitted.values=data_detrend,output.mean = output.mean,
+              input.mean = input.mean)
+  
+  class(est) <- "demean"
+  return(est)
+}
+
+#' Predict the centered values
+#' 
+#' Center an \code{idframe} object based on the training center means
+#' 
+#' @param object an object of class \code{idframe}
+#' @param newdata An optional idframe object in whic to look for variables with which
+#' to predict. If ommited, the original detrended idframe object is used
+#' 
+#' @return an \code{idframe} object
+#' 
+#' @examples
+#' ## Examples for train and test sets
+#' data(cstr)
+#' splitList <- dataPartition(cstr,p=0.6)
+#' train <- splitList$estimation # training set 
+#' test <- splitList$validation # testing set
+#' fit <- detrend.idframe(train)
+#' train_detrend <- predict(fit)
+#' test_detrend <- predict(fit,newdata=test)  
+#' @export
+predict.demean <- function(object,newdata=NULL,...){
+  
+  if(is.null(newdata)){
+    data <- fitted(object)
+  } else{
+    data <- newdata
+    data$output <- data$output - object$output.mean
+    data$input <- data$input - object$input.mean
+  }
+  return(data)
+}
diff --git a/R/detrend.R b/R/detrend.R
index 7f03753..5c646a2 100644
--- a/R/detrend.R
+++ b/R/detrend.R
@@ -1,6 +1,6 @@
 #' Remove linear trends
 #' 
-#' Removes the linear function from the input and output matrices. 
+#' Removes the linear trends in the input and output matrices. 
 #' 
 #' @param data an object of class \code{idframe}
 #'