rm(list=ls())
graphics.off()
# Here, I set the seed each time so that the results are comparable.
# This is useful as it means that anyone that runs your code, *should*
# get the same results as you, although random number generators change
# from time to time.
set.seed(1)
library("tidyverse")
library("SIBER")
# ******************************************************************************
# change this location per your local setup
load("data/demo.siber.data.2.rda")
# ******************************************************************************
siber.example <- createSiberObject(demo.siber.data.2)
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## A plot of the data
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palette(viridis::viridis(sum(siber.example$n.groups[2,])))
# Create lists of plotting arguments to be passed onwards to each
# of the three plotting functions.
community.hulls.args <- list(col = 1, lty = 1, lwd = 1)
group.ellipses.args <- list(n = 100, p.interval = 0.95, lty = 1, lwd = 2)
group.hull.args <- list(lty = 2, col = "grey20")
par(mfrow=c(1,1))
plotSiberObject(siber.example,
ax.pad = 2,
hulls = F, community.hulls.args,
ellipses = T, group.ellipses.args,
group.hulls = T, group.hull.args,
bty = "L",
iso.order = c(1,2),
xlab = expression({delta}^13*C~'permille'),
ylab = expression({delta}^15*N~'permille')
)
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## Summaries
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# Calculate summary statistics for each group: TA, SEA and SEAc
group.ML <- groupMetricsML(siber.example)
print(group.ML)
# Calculate the various Layman metrics on each of the communities.
community.ML <- communityMetricsML(siber.example)
print(community.ML)
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## Bayesian ellipses
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# options for running jags
parms <- list()
parms$n.iter <- 2 * 10^4 # number of iterations to run the model for
parms$n.burnin <- 1 * 10^3 # discard the first set of values
parms$n.thin <- 10 # thin the posterior by this many
parms$n.chains <- 2 # run this many chains
# define the priors
priors <- list()
priors$R <- 1 * diag(2)
priors$k <- 2
priors$tau.mu <- 1.0E-3
# fit the ellipses which uses an Inverse Wishart prior
# on the covariance matrix Sigma, and a vague normal prior on the
# means. Fitting is via the JAGS method.
ellipses.posterior <- siberMVN(siber.example, parms, priors)
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## check outputs from siberMVN for correct labelling
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# check the contents of ellipses.posterior as output by siberMVN and restrict
# it to the means of the isotopes for easy comparison to the raw data
t(as.data.frame(lapply(ellipses.posterior, colMeans))[5:6,])
# compare the means with those calculated from the raw data
demo.siber.data.2 %>% group_by(community, group) %>%
summarise(mu1 = mean(iso1), mu2 = mean(iso2))
# the orders are different, but the values of the means are correct
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## check SEA.B and SEAc estimates
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# The posterior estimates of the ellipses for each group can be used to
# calculate the SEA.B for each group.
SEA.B <- siberEllipses(ellipses.posterior)
# as per the introduction-to-siber vignette under the plotting, these columns
# are labelled in the same order as contained in the group.ML object
colnames(SEA.B) <- colnames(group.ML)
# we can calculate the mean SEA.B for each
colMeans(SEA.B)
# which seem to match the SEAc estimates close enough as they should
# certainly the order seems to be right!
group.ML[3,]
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