Consider here the case where, in some parametric inference problem, parameter is a point in the Simplex, For instance, consider some regression, on compositional data, > library(compositions) > data(DiagnosticProb) > Y=DiagnosticProb[,"type"]-1 > X=DiagnosticProb[,c("A","B","C")] > model = glm(Y~ilr(X),family=binomial) > b = ilrInv(coef(model)[-1],orig=X) > as.numeric(b) [1] 0.3447106 0.2374977 0.4177917 We can visualize that estimator on the simplex, using > tripoint=function(s){ + p=s/sum(s) + abc2xy(matrix(p,1,3)) + } > lab=LETTERS[1:3] > xl=c(-.1,1.25) > yl=c(-.1,1.15) >…

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