https://github.com/cran/fields
Tip revision: c71fb7f6ffa323303affebf0e35a0070faa9c24d authored by Doug Nychka on 10 May 2004, 00:00:00 UTC
version 1.7.2
version 1.7.2
Tip revision: c71fb7f
image.smooth.setup.r
"image.smooth.setup" <-
function (nrow = 64, ncol = 64, dx = 1, dy = 1, kernel.function = function(x){ exp(-abs(x))},
theta = 1, Mwidth = nrow, Nwidth = ncol, ...)
{
m <- nrow
n <- ncol
M2 <- round((m + Mwidth)/2)
N2 <- round((n + Nwidth)/2)
M <- 2 * M2
N <- 2 * N2
xi <- (1:M2) * dx
xi <- xi/theta
yi <- (1:N2) * dy
yi <- yi/theta
out <- kernel.function((matrix(xi, M2, N2)^2 + matrix(yi,
M2, N2, byrow = TRUE)^2), ...)/theta
out <- cbind(out, out[, N2:1])
out <- rbind(out, out[M2:1, ])
fft(out)/(M * N)
}