Eckerle4 {NISTnls}R Documentation

Circular interference data

Description

The Eckerle4 data frame has 35 rows and 2 columns giving transmittance as a function of wavelength.

Arguments

y A numeric vector of transmittance values.
x A numeric vector of wavelengths.

Format

This data frame contains the following columns:

Details

These data are the result of a NIST study involving circular interference transmittance. The response variable is transmittance, and the predictor variable is wavelength.

Source

Eckerle, K., NIST (197?). Circular Interference Transmittance Study.

Examples

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")