为什么在R中绘制高密度点曲线的output不平滑？

Question

This fact in basic R confuses me.

I am plotting a count histogram of my data and then overlaying the shape of the gamma distribution that I think underlies the data. The points on the gamma distribution are generated using dgamma and plotted using curve . No matter how many points I use to generate the curve, the output still looks pixellated. Does anyone know why and is it possible to obtain a smooth curve?

dt <- rgamma(100, shape = 2.59, scale = 0.16)

n <- 1000
x <- seq(min(dt), max(dt), length.out = n) 

hist(dt, freq = FALSE, ylim = c(0, 2.5), xlab = "D")
curve(dgamma(x, shape = 2.59, scale = 0.16), add = TRUE, lwd = 2, n = n)

Answer 1

curve has a n attribute that defaults to 101 you need to increase that. So note that not the datapoints you throw in determine your resolution.

curve(dgamma(x, shape = 2.59, scale = 0.16), add = TRUE, lwd = 2, n = n) # then it takes your defined n = 1000