Hi, Please also include R-help in your replies - I can't provide one-on-one tutorials.
Without knowing where you got your sample code, it's hard to help. But what are you trying to do? It doesn't have to be that complicated: x <- 1:10 y <- c(0.00, 0.00,0.0033,0.0009,0.0025,0.0653,0.1142,0.2872,0,1 ) plot(x, y, pch=20) # basic straight line of fit fit <- glm(y~x) abline(fit, col="blue", lwd=2) exp.lm <- lm(y ~ exp(x)) lines(1:10, predict(exp.lm, newdata=data.frame(x=1:10))) On Tue, Nov 27, 2018 at 9:34 AM Tolulope Adeagbo <tolulopeadea...@gmail.com> wrote: > > Hello, > > So I found this example online but there seems to be an issue with the > "Start" points. the result is giving somewhat a straight line > > # get underlying plot > x <- 1:10 > y <- c(0.00, 0.00,0.0033,0.0009,0.0025,0.0653,0.1142,0.2872,0,1 ) > plot(x, y, pch=20) > > # basic straight line of fit > fit <- glm(y~x) > co <- coef(fit) > abline(fit, col="blue", lwd=2) > > # exponential > f <- function(x,a,b) {a * exp(b * x)} > fit <- nls(y ~ f(x,a,b), start = c(a=1 , b=c(0,1))) > co <- coef(fit) > curve(f(x, a=co[1], b=co[2]), add = TRUE, col="green", lwd=2) > > > # exponential > f <- function(x,a,b) {a * exp(b * x)} > fit <- nls(y ~ f(x,a,b), start = c(a=1, b=1)) > co <- coef(fit) > curve(f(x, a=co[1], b=co[2]), add = TRUE, col="green", lwd=2) > # logarithmic > f <- function(x,a,b) {a * log(x) + b} > fit <- nls(y ~ f(x,a,b), start = c(a=1, b=1)) > co <- coef(fit) > curve(f(x, a=co[1], b=co[2]), add = TRUE, col="orange", lwd=2) > > # polynomial > f <- function(x,a,b,d) {(a*x^2) + (b*x) + d} > fit <- nls(y ~ f(x,a,b,d), start = c(a=1, b=1, d=1)) > co <- coef(fit) > curve(f(x, a=co[1], b=co[2], d=co[3]), add = TRUE, col="pink", lwd=2) > > On Tue, Nov 27, 2018 at 12:28 PM Sarah Goslee <sarah.gos...@gmail.com> wrote: >> >> Hi, >> >> Using rseek.org to search for exponential regression turns up lots of >> information, as does using Google. >> >> Which tutorials have you worked thru already, and what else are you looking >> for? >> >> Sarah >> >> On Tue, Nov 27, 2018 at 5:44 AM Tolulope Adeagbo <tolulopeadea...@gmail.com> >> wrote: >>> >>> Good day, >>> Please i nee useful materials to understand how to use R for exponential >>> regression. >>> Many thanks. >> -- Sarah Goslee (she/her) http://www.numberwright.com ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.