self start for an exponential-plateau function
Self starter for an exponential-plateau function
expfp(x, a, c, xs) SSexpfp(x, a, c, xs)
x |
input vector (x) |
a |
represents the value at x = 0 |
c |
represents the exponential rate |
xs |
represents the breakpoint at which the plateau starts |
This is the exponential-plateua function, where ‘xs’ is the break-point
(x < xs) * a * exp(c * x) + (x >= xs) * (a * exp(c * xs))
For more details see: Archontoulis and Miguez (2015) - (doi:10.2134/agronj2012.0506).
a numeric vector of the same length as x containing parameter estimates for equation specified
expfp: vector of the same length as x using the expfp function
require(ggplot2) set.seed(12345) x <- 1:30 y <- expfp(x, 10, 0.1, 15) + rnorm(30, 0, 1.5) dat <- data.frame(x = x, y = y) fit <- nls(y ~ SSexpfp(x, a, c, xs), data = dat) ## plot ggplot(data = dat, aes(x = x, y = y)) + geom_point() + geom_line(aes(y = fitted(fit)))
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