Bennett5 {NISTnls}

Magentization modelling

Description

The Bennett5 data frame has 154 rows and 2 columns of data from a magnetism study

Format

This data frame contains the following columns:

y

A numeric vector of magnetism values.

x

A numeric vector of log(time).

Details

These data are the result of a NIST study involving superconductivity magnetization modeling. The response variable is magnetism, and the predictor variable is the log of time in minutes.

Source

Bennett, L., L. Swartzendruber, and H. Brown, NIST (1994). Superconductivity Magnetization Modeling.

Examples

Try <- function(expr) if (!inherits(val <- try(expr), "try-error")) val
plot(y ~ x, data = Bennett5)
Try(fm1 <- nls(y ~ b1*(b2+x)**(-1/b3), data = Bennett5,
           start = c(b1 = -2000, b2 = 50, b3 = 0.8), trace = TRUE))
Try(fm1a <- nls(y ~ b1*(b2+x)**(-1/b3), data = Bennett5,
            start = c(b1 = -2000, b2 = 50, b3 = 0.8),
            trace = TRUE, alg = "port"))
Try(fm2 <- nls(y ~ b1*(b2+x)**(-1/b3), data = Bennett5,
           start = c(b1 = -1500, b2 = 45, b3 = 0.85), trace = TRUE))
Try(fm2a <- nls(y ~ b1*(b2+x)**(-1/b3), data = Bennett5,
            start = c(b1 = -1500, b2 = 45, b3 = 0.85),
            trace = TRUE, alg = "port"))
Try(fm3 <- nls(y ~ (b2+x)**(-1/b3), data = Bennett5, alg = "plinear",
           start = c( b2 = 50, b3 = 0.8), trace = TRUE))
Try(fm4 <- nls(y ~ (b2+x)**(-1/b3), data = Bennett5, alg = "plinear",
           start = c( b2 = 45, b3 = 0.8), trace = TRUE))