Returns the accumulated "error rate" of node under the tests previously performed with test. This is the fraction of times the Net predicted or diagnosed states incorrectly for node, out of all the cases which provided a value for node.

For each case, the "prediction" is formed by reading the values of the "observed nodes" of that case in the file, using them to update beliefs in the net, and then picking the state of node which has the highest resultant belief (posterior probability) to be the prediction. The set of "observed nodes" is specified when creating the tester_bn.

A result of 0.0 means no prediction errors, whereas a result of 1.0 means all predictions were in error.

node is required to have been in the test_nodes list originally passed to NewNetTester_bn.