I'm trying grnn package, and reproduced the example ( http://cran.r-project.org/web/packages/grnn/grnn.pdf), I tried the example with another x input column in the dataset (see below): but I'm getting the following error "Error in Ya * patterns1 : non-conformable arrays", though I took care to pass an input of length 2 n <- 100 set.seed(1) x1 <- runif(n, -2, 2) x2 = x1^2 y0 <- x1 * x2 epsilon <- rnorm(n, 0, .1) y <- y0 + epsilon grnn <- learn(data.frame(y,x1, x2)) grnn <- smooth(grnn,sigma=0.1) guess(grnn, c(2,4)) *Error in Ya * patterns1 : non-conformable arrays* guess(grnn, data.frame(x1=c(2), x2=c(4))) *Error in (X - Xa) %*% t(X - Xa) : * * requires numeric/complex matrix/vector arguments* [[alternative HTML version deleted]]