optimize
Hi Muhammad, On Mon, Jan 3, 2011 at 6:52 AM, Muhammad Rahiz
<muhammad.rahiz at ouce.ox.ac.uk> wrote:
Hi all, I'm trying to get the value of y when x=203 by using the intersect of three curves. The horizontal curve does not meet with the other two. How can I rectify the code below?
What is your code supposed to do? This is one way to get three intersecting curves, but I am not sure it is doing what you were hoping to do with the sample code you sent. ts <- seq(200, 209, 1) dd <- c(NA,NA,NA,NA,1.87,1.83,1.86,NA,1.95,1.96) xy <- lm(dd ~ ts) plot(x = ts, y = dd, ylim = c(1.5,2)) abline(xy, col = "blue", lty = 2) abline(v = 203, h = predict(xy, data.frame(ts = 203)), col = "blue", lty = 2) Best regards, Josh
Thanks Muhammad ?ts <- 1:10 ?dd <- 10:1 ?ts <- seq(200,209,1) ?dd <- c(NA,NA,NA,NA,1.87,1.83,1.86,NA,1.95,1.96) ?plot(ts,dd,ylim=c(1.5,2)) ?abline(lm(dd~ts),col="blue",lty=2) ?abline(v=203,col="blue",lty=2) ?xy <- lm(dd~ts) ?fc <- function(x) coef(xy)[1] + x*coef(xy)[2] ?val <- optimize(f=function(x) abs(fc(x)-203),c(1.5,2)) ?abline(h=val,col="blue",lty=2)
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Joshua Wiley Ph.D. Student, Health Psychology University of California, Los Angeles http://www.joshuawiley.com/