"rad.cov" <-
function (x1, x2, p = 1, with.log = TRUE, with.constant = TRUE, C = NULL) 
{
    if (is.null(C)) {
        if (!is.matrix(x1)) 
            x1 <- as.matrix(x1)
        if (!is.matrix(x2)) 
            x2 <- as.matrix(x2)
        d <- ncol(x1)
        n1 <- nrow(x1)
        n2 <- nrow(x2)
        m <- (d + p)/2
        par <- c(p/2, ifelse((d%%2 == 0) & (with.log), 1, 0))
        temp <- .Fortran("radbas", nd = as.integer(d), x1 = as.double(x1), 
            n1 = as.integer(n1), x2 = as.double(x2), n2 = as.integer(n2), 
            par = as.double(par), k = as.double(rep(0, n1 * n2)))
        if (with.constant) {
            Amd <- radbas.constant(m, d)
        }
        else {
            Amd <- 1
        }
        Amd * matrix(temp$k, ncol = n2, nrow = n1)
    }
    else {
        rad.covC(x1, x2, p = p, with.log = with.log, with.constant = with.constant, 
            C = C)
    }
}