creating a triangular matrix

Question

There must an elegant way to do this but I can\'t figure out so:

Columns are probabilities from 1 to 0 going right

Rows are probabilities from 0 to 1 going d

Answer 1

require(matlab)
x=matrix(seq(0,1,.1),1)
X=x[rep(1,c(11)),]
X[upper.tri(X)]=NA
X=t(X)
for(a in 1:11){
  X[1:a,a]=rev(X[1:a,a])
}
X=flipud(X)
colnames(X) <- seq(1,0,by=-.1)
rownames(X) <- seq(0,1,by=.1)