Convert back to lower triangular matrix

Given a vector;> ab = seq(0.5,1, by=0.1)> ab[1] 0.5 0.6 0.7 0.8 0.9 1.0
The euclidean distance between the vector elements is given by the lower triangular matrix?> dd1 = dist(ab,"euclidean")> dd1? ? 1 ? 2 ? 3 ? 4 ? 52 0.1 ? ? ? ? ? ? ? ?3 0.2 0.1 ? ? ? ? ? ?4 0.3 0.2 0.1 ? ? ? ?5 0.4 0.3 0.2 0.1 ? ?6 0.5 0.4 0.3 0.2 0.1
Convert the lower triangular matrix to a full matrix> ddm = as.matrix(dd1)> ddm? ? 1 ? 2 ? 3 ? 4 ? 5 ? 61 0.0 0.1 0.2 0.3 0.4 0.52 0.1 0.0 0.1 0.2 0.3 0.43 0.2 0.1 0.0 0.1 0.2 0.34 0.3 0.2 0.1 0.0 0.1 0.25 0.4 0.3 0.2 0.1 0.0 0.16 0.5 0.4 0.3 0.2 0.1 0.0
I would be grateful if someone could provide me with a code to convert ddm to the lower triangular matrix as before i.e. dd1
?above.