Adding R example with .r extension

samples/R/df.residual.r

@@ -0,0 +1,29 @@
+
+df.residual.mira <- function(object, ...) {
+    fit <- object$analyses[[1]]
+    return(df.residual(fit))
+}
+
+df.residual.lme <- function(object, ...) {
+    return(object$fixDF[["X"]][1])
+}
+
+df.residual.mer <- function(object, ...) {
+    return(sum(object@dims[2:4] * c(1, -1, -1)) + 1)
+}
+
+df.residual.default <- function(object, q = 1.3, ...) {
+    df <- object$df.residual
+    if (!is.null(df)) 
+        return(df)
+    
+    mk <- try(c <- coef(object), silent = TRUE)
+    mn <- try(f <- fitted(object), silent = TRUE)
+    if (inherits(mk, "try-error") | inherits(mn, "try-error")) 
+        return(NULL)
+    n <- ifelse(is.data.frame(f) | is.matrix(f), nrow(f), length(f))
+    k <- length(c)
+    if (k == 0 | n == 0) 
+        return(NULL)
+    return(max(1, n - q * k))
+}