pub fn skye() -> Result<DataFrame, PolarsError>Expand description
§AFM Compositions of Aphyric Skye Lavas
§Description:
The ‘Skye’ data frame has 23 rows and 3 columns.
§Usage:
Skye
§Format:
This data frame contains the following columns:
- ‘A’ Percentage of sodium and potassium oxides.
- ‘F’ Percentage of iron oxide.
- ‘M’ Percentage of magnesium oxide.
§Source:
R. N. Thompson, J. Esson and A. C. Duncan (1972) Major element chemical variation in the Eocene lavas of the Isle of Skye. J. Petrology, 13, 219-253.
§References:
J. Aitchison (1986) The Statistical Analysis of Compositional Data. Chapman and Hall, p.360.
Venables, W. N. and Ripley, B. D. (2002) Modern Applied Statistics with S. Fourth edition. Springer.
§Examples:
# ternary() is from the on-line answers.
ternary <- function(X, pch = par("pch"), lcex = 1,
add = FALSE, ord = 1:3, ...)
{
X <- as.matrix(X)
if(any(X < 0)) stop("X must be non-negative")
s <- drop(X %*% rep(1, ncol(X)))
if(any(s<=0)) stop("each row of X must have a positive sum")
if(max(abs(s-1)) > 1e-6) {
warning("row(s) of X will be rescaled")
X <- X / s
}
X <- X[, ord]
s3 <- sqrt(1/3)
if(!add)
{
oldpty <- par("pty")
on.exit(par(pty=oldpty))
par(pty="s")
plot(c(-s3, s3), c(0.5-s3, 0.5+s3), type="n", axes=FALSE,
xlab="", ylab="")
polygon(c(0, -s3, s3), c(1, 0, 0), density=0)
lab <- NULL
if(!is.null(dn <- dimnames(X))) lab <- dn[[2]]
if(length(lab) < 3) lab <- as.character(1:3)
eps <- 0.05 * lcex
text(c(0, s3+eps*0.7, -s3-eps*0.7),
c(1+eps, -0.1*eps, -0.1*eps), lab, cex=lcex)
}
points((X[,2] - X[,3])*s3, X[,1], ...)
}
ternary(Skye/100, ord=c(1,3,2))