Eckerle4 {NISTnls} | R Documentation |
The Eckerle4
data frame has 35 rows and 2 columns giving
transmittance as a function of wavelength.
y |
A numeric vector of transmittance values. |
x |
A numeric vector of wavelengths. |
This data frame contains the following columns:
These data are the result of a NIST study involving circular interference transmittance. The response variable is transmittance, and the predictor variable is wavelength.
Eckerle, K., NIST (197?). Circular Interference Transmittance Study.
library(NISTnls) data(Eckerle4) plot(y ~ x, data = Eckerle4) ## should fail - ridiculous starting value for b3 fm1 <- nls(y ~ (b1/b2) * exp(-0.5*((x-b3)/b2)**2), data = Eckerle4, trace = TRUE, start = c(b1 = 1, b2 = 10, b3 = 500)) fm2 <- nls(y ~ (b1/b2) * exp(-0.5*((x-b3)/b2)**2), data = Eckerle4, trace = TRUE, start = c(b1 = 1.5, b2 = 5, b3 = 450)) ## should fail - ridiculous starting value for b3 fm3 <- nls(y ~ (1/b2) * exp(-0.5*((x-b3)/b2)**2), data = Eckerle4, trace = TRUE, start = c(b2 = 10, b3 = 500), algorithm = "plinear") fm4 <- nls(y ~ (1/b2) * exp(-0.5*((x-b3)/b2)**2), data = Eckerle4, trace = TRUE, start = c(b2 = 5, b3 = 450), algorithm = "plinear")