diff options
Diffstat (limited to 'R/lod.R')
| -rw-r--r-- | R/lod.R | 23 |
1 files changed, 15 insertions, 8 deletions
@@ -10,18 +10,25 @@ lod.default <- function(object, ..., alpha = 0.05, beta = 0.05) lod.lm <- function(object, ..., alpha = 0.05, beta = 0.05) { - y0 <- predict(object, data.frame(x = 0), interval="prediction", - level = 1 - alpha) + xname <- names(object$model)[[2]] + newdata <- data.frame(0) + names(newdata) <- xname + y0 <- predict(object, newdata, interval="prediction", + level = 1 - 2 * alpha ) yc <- y0[[1,"upr"]] xc <- inverse.predict(object,yc)[["Prediction"]] f <- function(x) { - # Here I need the variance of y values as a function of x or - # y values - # Strangely, setting the confidence level to 0.5 does not result - # in a zero confidence or prediction interval + newdata <- data.frame(x) + names(newdata) <- xname + pi.y <- predict(object, newdata, interval = "prediction", + level = 1 - 2 * beta) + yd <- pi.y[[1,"lwr"]] + (yd - yc)^2 } - lod.x <- optimize(f,interval=c(0,max(object$model$x)))$minimum - lod.y <- predict(object, data.frame(x = lod.x)) + lod.x <- optimize(f,interval=c(0,max(object$model[[xname]])))$minimum + newdata <- data.frame(x = lod.x) + names(lod.x) <- xname + lod.y <- predict(object, data.frame(lod.x)) return(list(x = lod.x, y = lod.y)) } |