How to plot PDF which is in the form of orthogonal polynomial
Have you considered "cumsum(exp(-polynomial))"?
Consider for example the following:
library(polynom)
b. <- polynomial(1:5)
x <- seq(-2, 2, length=101)
b.p <- predict(b., x)
plot(x, b.p)
plot(x, exp(-b.p))
cdf <- cumsum(exp(-b.p))
plot(cdf/cdf[101])
hope this helps. spencer graves
Yong Wang wrote:
Dear all using the orthogonal polymial on a set of data, I get an approximate density which basically is in the form: exp(-polynomial), as you know, the parameters are the converged coeeficients. obviously, It is hard, if not impossible, to use the inverse CDF method to get a sample and then plot density. then how can I plot the approximated density in order to have a graphical comparision with the real data's histogram. any hint is appreciated thanks
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