Description Format Details Source Examples
The Eckerle4
data frame has 35 rows and 2 columns giving
transmittance as a function of wavelength.
This data frame contains the following columns:
A numeric vector of transmittance values.
A numeric vector of wavelengths.
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.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21  Try < function(expr) if (!inherits(val < try(expr), "tryerror")) val
plot(y ~ x, data = Eckerle4)
## should fail  ridiculous starting value for b3
Try(fm1 < nls(y ~ (b1/b2) * exp(0.5*((xb3)/b2)**2), Eckerle4,
trace = TRUE,
start = c(b1 = 1, b2 = 10, b3 = 500)))
Try(fm1a < nls(y ~ (b1/b2) * exp(0.5*((xb3)/b2)**2), Eckerle4,
trace = TRUE, alg = "port",
start = c(b1 = 1, b2 = 10, b3 = 500)))
Try(fm2 < nls(y ~ (b1/b2) * exp(0.5*((xb3)/b2)**2),
Eckerle4, trace = TRUE,
start = c(b1 = 1.5, b2 = 5, b3 = 450)))
Try(fm2a < nls(y ~ (b1/b2) * exp(0.5*((xb3)/b2)**2),
Eckerle4, trace = TRUE, alg = "port",
start = c(b1 = 1.5, b2 = 5, b3 = 450)))
## should fail  ridiculous starting value for b3
Try(fm3 < nls(y ~ (1/b2) * exp(0.5*((xb3)/b2)**2),
Eckerle4, trace = TRUE,
start = c(b2 = 10, b3 = 500), algorithm = "plinear"))
Try(fm4 < nls(y ~ (1/b2) * exp(0.5*((xb3)/b2)**2), Eckerle4, trace = TRUE,
start = c(b2 = 5, b3 = 450), algorithm = "plinear"))

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