Matrix symmetry might depend on numerical precision issues. The older version of JAGS had a bug related to this issue for multivariate normal nodes. This simple function can fix the issue, but new JAGS versions do not require such intervention.
A square matrix.
The function takes the average as
(x[i, j] + x[j, i]) / 2
for each off diagonal cells.
A symmetric square matrix.
The function works for any matrix, even for those not intended to be symmetric.
Peter Solymos, email@example.com
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