Hi Alice,
tck2connectome currently outputs upper triangular matrices only; though I suspect I’ll have to add an option in there to output symmetric matrices, since some people seem to want them. Beware though: it may erroneously affect certain matrix operations…
In Matlab, the best way to make the matrix M symmetric (regardless of whether or not the diagonal is zeroed) is to do:
M = M + triu(M,1)';
That takes the upper triangular part of the matrix (excluding the diagonal), transposes it, then adds this to the original matrix. Voila, symmetric matrix!
Best regards
Rob