SSharm: self start for a harmonic regression model

In nlraa: Nonlinear Regression for Agricultural Applications

self start for a harmonic regression model

Description

Self starter for a harmonic regression

Usage

harm1(x, b0, b1, cos1, sin1)

SSharm1(x, b0, b1, cos1, sin1)

Arguments

x	input vector
b0	intercept of the harmonic regression
b1	slope of the harmonic regression
cos1	coefficient associated with the cosine of the harmonic regression
sin1	coefficient associated with the sine of the harmonic regression

Details

Harmonic regression is actually a type of linear regression. Just adding it for convenience.

Value

a numeric vector of the same length as x containing parameter estimates for equation specified

harm1: vector of the same length as x using a harmonic regression

Examples

require(ggplot2)
set.seed(1234)
x <- seq(0, 3, length.out = 100)
y <- harm1(x, 0, 0, 0.05, 0) + rnorm(length(x), 0, 0.002)
dat <- data.frame(x = x, y = y)
fit <- nls(y ~ SSharm1(x, b0, b1, cos1, sin1), data = dat)
## plot
ggplot(data = dat, aes(x = x, y = y)) + 
  geom_point() + 
  geom_line(aes(y = fitted(fit)))

nlraa documentation built on May 29, 2024, 2:01 a.m.