> axp <- par("xaxp") #-> powers of 10 inside 'usr' > axp[3] <- 1 # such that only 10^. are labeled > aX <- axTicks(1, axp = axp) > xu <- 10 ^ par("usr")[1:2] > e10 <- c(-1,1) + round(log10(axp[1:2])) ## exponents of 10 outside 'usr' > v <- c(outer(1:9, e10[1]:e10[2], function(x,E) x * 10 ^ E)) > v <- v[xu[1] <= v & v <= xu[2]]