https://www.tensorflow.org/probability/api_docs/python/tfp/substrates/numpy/distributions/JointDistributionNamed
tfp.substrates.numpy.distributions.JointDistributionNamed | TensorFlow Probability
Joint distribution parameterized by named distribution-making functions.
tfpsubstratesnumpydistributionstensorflow
https://groups.google.com/a/tensorflow.org/g/tfprobability/c/afy3uf8CKPg
target_log_prob_fn for JointDistributionNamed
targetlogprobfn