##################################################################
## R code (R Code Development Team 2004 - www.r-project.org) to
## calculate Information Criterion (IC) weights from text outputs
## derived from 'Interactive Individual Identification Software'
## (I3S),formerly known as 'Individual Raggie Identification
## System' (IRIS). Available from www.reijns.com/i3s.
##################################################################

#################################################
## Code developed by CJA Bradshaw & CW Speed ©
## Charles Darwin Universtiy, Darwin, Australia
## Email: corey.bradshaw@cdu.edu.au
## September 2006
#################################################

############################################################################
## This code accompanies the manuscript entitled:
## Spot the match – wildlife photo-identification using information theory
## by CW Speed, MG Meekan, CJA Bradshaw
## Frontiers in Zoology
############################################################################


## Establish target folder containing I3S text outputs (e.g.)
folder <- "C:/"

## Establish I3S text output of scores
file <- "file.name"

## Calculate Information Criteria and weights
target.file <- paste(folder,file,sep="")

## Import data
dat <- read.table(target.file,header=F) 	
colnames(dat) <- c("image","spots","score")

## Information Criterion
IC <- 2+((100*(1/dat$spots))*log((dat$score*dat$spots^2)/(100*(1/dat$spots))))
IC <- IC[-1]

## delta IC
dIC <- IC - min(IC)

## IC weight
wIC <- (exp(-0.5*dIC))/sum(exp(-0.5*dIC))

## Best matching image IC weight
best.ICw <- wIC[1]

## Best matching image information-theoretic evidence ratio (ER)
best.ER <- wIC[1]/wIC[2]

## Best imate statistics
print(paste("best image file name =",dat$image[1]))
print(paste("IC weight =",best.ICw))
print(paste("IC evidence ratio =",best.ER))