style cleanup, incomplete CV

R-package/R/utils.R

@@ -81,20 +81,28 @@ xgb.predict <- function(booster, dmat, outputmargin = FALSE) {
 
 ## ----the following are low level iteratively function, not needed if
 ## you do not want to use them ---------------------------------------
-
+# get dmatrix from data, label
-# iteratively update booster with dtrain
+xgb.get.DMatrix <- function(data, label = NULL) {
-xgb.iter.update <- function(booster, dtrain, iter) {
+  inClass <- class(data)
-  if (class(booster) != "xgb.Booster") {
+  if (inClass == "dgCMatrix" || inClass == "matrix") {
-    stop("xgb.iter.update: first argument must be type xgb.Booster")
+    if (is.null(label)) {
+      stop("xgboost: need label when data is a matrix")
     }
-  if (class(dtrain) != "xgb.DMatrix") {
+    dtrain <- xgb.DMatrix(data, label = label)
-    stop("xgb.iter.update: second argument must be type xgb.DMatrix")
+  } else {
+    if (!is.null(label)) {
+      warning("xgboost: label will be ignored.")
     }
-  .Call("XGBoosterUpdateOneIter_R", booster, as.integer(iter), dtrain, 
+    if (inClass == "character") {
-        PACKAGE = "xgboost")
+      dtrain <- xgb.DMatrix(data)
-  return(TRUE)
+    } else if (inClass == "xgb.DMatrix") {
+      dtrain <- data
+    } else {
+      stop("xgboost: Invalid input of data")
+    }
+  }
+  return (dtrain)
 }
-
 # iteratively update booster with customized statistics
 xgb.iter.boost <- function(booster, dtrain, gpair) {
   if (class(booster) != "xgb.Booster") {
@@ -108,8 +116,28 @@ xgb.iter.boost <- function(booster, dtrain, gpair) {
   return(TRUE)
 }
 
+# iteratively update booster with dtrain
+xgb.iter.update <- function(booster, dtrain, iter, obj = NULL) {
+  if (class(booster) != "xgb.Booster") {
+    stop("xgb.iter.update: first argument must be type xgb.Booster")
+  }
+  if (class(dtrain) != "xgb.DMatrix") {
+    stop("xgb.iter.update: second argument must be type xgb.DMatrix")
+  }
+
+  if (is.null(obj)) {
+    .Call("XGBoosterUpdateOneIter_R", booster, as.integer(iter), dtrain, 
+          PACKAGE = "xgboost")
+  } else {
+    pred <- xgb.predict(bst, dtrain)
+    gpair <- obj(pred, dtrain)
+    succ <- xgb.iter.boost(bst, dtrain, gpair)
+  }
+  return(TRUE)
+}
+
 # iteratively evaluate one iteration
-xgb.iter.eval <- function(booster, watchlist, iter) {
+xgb.iter.eval <- function(booster, watchlist, iter, feval = NULL) {
   if (class(booster) != "xgb.Booster") {
     stop("xgb.eval: first argument must be type xgb.Booster")
   }
@@ -122,6 +150,7 @@ xgb.iter.eval <- function(booster, watchlist, iter) {
     }
   }
   if (length(watchlist) != 0) {
+    if (is.null(feval)) {
       evnames <- list()
       for (i in 1:length(watchlist)) {
         w <- watchlist[i]
@@ -132,8 +161,36 @@ xgb.iter.eval <- function(booster, watchlist, iter) {
       }
       msg <- .Call("XGBoosterEvalOneIter_R", booster, as.integer(iter), watchlist, 
                    evnames, PACKAGE = "xgboost")
+    } else {
+      msg <- paste("[", iter, "]", sep="")
+      for (j in 1:length(watchlist)) {
+        w <- watchlist[j]
+        if (length(names(w)) == 0) {
+          stop("xgb.eval: name tag must be presented for every elements in watchlist")
+        }
+        ret <- feval(xgb.predict(bst, w[[1]]), w[[1]])
+        msg <- paste(msg, "\t", names(w), "-", ret$metric, ":", ret$value, sep="")
+      }
+    }
   } else {
     msg <- ""
   }  
   return(msg)
 } 
+#------------------------------------------
+# helper functions for cross validation
+#
+xgb.cv.mknfold <- function(dall, nfold, param, metrics=list(), fpreproc = NULL) {  
+  randidx <- sample(1 : xgb.numrow(dall))
+  kstep <- length(randidx) / nfold
+  idset <- list()
+  for (i in 1:nfold) {
+    idset = append(idset, randidx[ ((i-1) * kstep + 1) : min(i * kstep, length(randidx)) ])
+  }
+  ret <- list()
+  for (k in 1:nfold) {
+    
+  }
+  
+}
+

R-package/R/xgb.cv.R

@@ -0,0 +1,57 @@
+#' eXtreme Gradient Boosting Training
+#' 
+#' The training function of xgboost
+#'
+#' @param params the list of parameters. Commonly used ones are:
+#' \itemize{
+#'   \item \code{objective} objective function, common ones are
+#'   \itemize{
+#'     \item \code{reg:linear} linear regression
+#'     \item \code{binary:logistic} logistic regression for classification
+#'   }
+#'   \item \code{eta} step size of each boosting step
+#'   \item \code{max_depth} maximum depth of the tree
+#'   \item \code{nthread} number of thread used in training, if not set, all threads are used
+#' }
+#'
+#'   See \url{https://github.com/tqchen/xgboost/wiki/Parameters} for 
+#'   further details. See also inst/examples/demo.R for walkthrough example in R.
+#' @param data takes an \code{xgb.DMatrix} as the input.
+#' @param nrounds the max number of iterations
+#' @param metrics, list of evaluation metrics to be used in corss validation,
+#'   when it is not specified, the evaluation metric is chosen according to objective function.
+#'   Possible options are:
+#' \itemize{
+#'   \item \code{error} binary classification error rate
+#'   \item \code{rmse} Rooted mean square error
+#'   \item \code{logloss} negative log-likelihood function
+#'   \item \code{auc} Area under curve
+#'   \item \code{merror} Exact matching error, used to evaluate multi-class classification
+#' }
+#'
+#' @param obj customized objective function. Returns gradient and second order 
+#'   gradient with given prediction and dtrain, 
+#' @param feval custimized evaluation function. Returns 
+#'   \code{list(metric='metric-name', value='metric-value')} with given 
+#'   prediction and dtrain,
+#' @param ... other parameters to pass to \code{params}.
+#' 
+#' @details 
+#' This is the cross validation function for xgboost
+#'
+#' Parallelization is automatically enabled if OpenMP is present.
+#' Number of threads can also be manually specified via "nthread" parameter.
+#' 
+#' This function only accepts an \code{xgb.DMatrix} object as the input.
+#'
+#' @export
+#'
+xgb.cv <- function(params=list(), data, nrounds, metrics=list(), label = NULL,
+                   obj = NULL, feval = NULL, ...) {
+  if (typeof(params) != "list") {
+    stop("xgb.cv: first argument params must be list")
+  }
+  dtrain <- xgb.get.DMatrix(data, label)
+  params = append(params, list(...))
+  
+}

R-package/R/xgb.train.R

@@ -16,7 +16,7 @@
 #'
 #'   See \url{https://github.com/tqchen/xgboost/wiki/Parameters} for 
 #'   further details. See also inst/examples/demo.R for walkthrough example in R.
-#' @param dtrain takes an \code{xgb.DMatrix} as the input.
+#' @param data takes an \code{xgb.DMatrix} as the input.
 #' @param nrounds the max number of iterations
 #' @param watchlist what information should be printed when \code{verbose=1} or
 #'   \code{verbose=2}. Watchlist is used to specify validation set monitoring
@@ -64,8 +64,9 @@
 #' bst <- xgb.train(param, dtrain, nround = 2, watchlist, logregobj, evalerror)
 #' @export
 #' 
-xgb.train <- function(params=list(), dtrain, nrounds, watchlist = list(), 
+xgb.train <- function(params=list(), data, nrounds, watchlist = list(), 
                       obj = NULL, feval = NULL, ...) {
+  dtrain <- data
   if (typeof(params) != "list") {
     stop("xgb.train: first argument params must be list")
   }
@@ -75,37 +76,10 @@ xgb.train <- function(params=list(), dtrain, nrounds, watchlist = list(),
   params = append(params, list(...))
   bst <- xgb.Booster(params, append(watchlist, dtrain))
   for (i in 1:nrounds) {
-    if (is.null(obj)) {
+    succ <- xgb.iter.update(bst, dtrain, i - 1, obj)
-      succ <- xgb.iter.update(bst, dtrain, i - 1)
-    } else {
-      pred <- xgb.predict(bst, dtrain)
-      gpair <- obj(pred, dtrain)
-      succ <- xgb.iter.boost(bst, dtrain, gpair)
-    }
     if (length(watchlist) != 0) {
-      if (is.null(feval)) {
+      msg <- xgb.iter.eval(bst, watchlist, i - 1, feval)
-        msg <- xgb.iter.eval(bst, watchlist, i - 1)
+      cat(paste(msg, "\n", sep=""))
-        cat(msg)
-        cat("\n")
-      } else {
-        cat("[")
-        cat(i)
-        cat("]")
-        for (j in 1:length(watchlist)) {
-          w <- watchlist[j]
-          if (length(names(w)) == 0) {
-            stop("xgb.eval: name tag must be presented for every elements in watchlist")
-          }
-          ret <- feval(xgb.predict(bst, w[[1]]), w[[1]])
-          cat("\t")
-          cat(names(w))
-          cat("-")
-          cat(ret$metric)
-          cat(":")
-          cat(ret$value)
-        }
-        cat("\n")
-      }
     }
   }
   return(bst)

R-package/R/xgboost.R

@@ -40,19 +40,7 @@
 #' 
 xgboost <- function(data = NULL, label = NULL, params = list(), nrounds, 
                     verbose = 1, ...) {
-  inClass <- class(data)
+  dtrain <- xgb.get.DMatrix(data, label)
-  if (inClass == "dgCMatrix" || inClass == "matrix") {
-    if (is.null(label)) 
-      stop("xgboost: need label when data is a matrix")
-    dtrain <- xgb.DMatrix(data, label = label)
-  } else {
-    if (!is.null(label)) 
-      warning("xgboost: label will be ignored.")
-    if (inClass == "character") 
-      dtrain <- xgb.DMatrix(data) else if (inClass == "xgb.DMatrix") 
-      dtrain <- data else stop("xgboost: Invalid input of data")
-  }
-  
   if (verbose > 1) {
     silent <- 0 
   } else {
@@ -62,8 +50,11 @@ xgboost <- function(data = NULL, label = NULL, params = list(), nrounds,
   params <- append(params, list(silent = silent))
   params <- append(params, list(...))
   
-  if (verbose > 0) 
+  if (verbose > 0) {
-    watchlist <- list(train = dtrain) else watchlist <- list()
+    watchlist <- list(train = dtrain)
+  } else {
+    watchlist <- list()
+  }
   
   bst <- xgb.train(params, dtrain, nrounds, watchlist)