self start for linear-plateau function
Self starter for linear-plateau function with parameters a (intercept), b (slope), xs (break-point)
linp(x, a, b, xs) SSlinp(x, a, b, xs)
x |
input vector |
a |
the intercept |
b |
the slope |
xs |
break-point of transition between linear and plateau |
This function is linear when x < xs: (a + b * x) and flat (asymptote = a + b * xs) when x >= xs.
a numeric vector of the same length as x containing parameter estimates for equation specified
linp: vector of the same length as x using the linear-plateau function
package segmented.
require(ggplot2) set.seed(123) x <- 1:30 y <- linp(x, 0, 1, 20) + rnorm(30, 0, 0.5) dat <- data.frame(x = x, y = y) fit <- nls(y ~ SSlinp(x, a, b, xs), data = dat) ## plot ggplot(data = dat, aes(x = x, y = y)) + geom_point() + geom_line(aes(y = fitted(fit))) ## Confidence intervals confint(fit)
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