1 files changed, 25 insertions, 0 deletions
diff --git a/R/lod.R b/R/lod.R
new file mode 100644
index 0000000..9f90d48
--- /dev/null
+++ b/R/lod.R
@@ -0,0 +1,25 @@
+lod <- function(object, ..., alpha = 0.05, k = 1, n = 1, w = "auto")
+{
+  UseMethod("lod")
+}
+
+loq <- function(object, ..., alpha = 0.05, k = 3, n = 1, w = "auto")
+{
+  lod(object = object, alpha = alpha, k = k, n = n, w = w)
+}
+
+lod.default <- function(object, ..., alpha = 0.05, k = 1, n = 1, w = "auto")
+{
+  stop("lod is only implemented for univariate lm objects.")
+}
+
+lod.lm <- function(object, ..., alpha = 0.05, k = 1, n = 1, w = "auto")
+{
+  f <- function(x) {
+    y <- predict(object, data.frame(x = x))
+    p <- inverse.predict(object, rep(y, n), ws = w, alpha = alpha)
+    (p[["Prediction"]] - k * p[["Confidence"]])^2
+  }
+  tmp <- optimize(f,interval=c(0,max(object$model$x)))
+  return(tmp$minimum)
+}