refinement of R package

R-package/R/xgb.DMatrix.save.R

@@ -0,0 +1,12 @@
+# save model or DMatrix to file 
+xgb.DMatrix.save <- function(handle, fname) {
+    if (typeof(fname) != "character") {
+        stop("xgb.save: fname must be character")
+    }
+    if (class(handle) == "xgb.DMatrix") {
+        .Call("XGDMatrixSaveBinary_R", handle, fname, as.integer(FALSE), PACKAGE="xgboost")
+        return(TRUE)
+    }
+    stop("xgb.save: the input must be either xgb.DMatrix or xgb.Booster")
+    return(FALSE)
+}