AIMA.Probability.ProbabilityModel.posterior C# (CSharp) Метод

        protected abstract double posterior(IProposition phi, params IProposition[] evidence);

        // AIMA3e pg. 496
        protected void test_MeningitisStiffNeckModel(ProbabilityModel model)
        {

            Assert.IsTrue(model.isValid());

            AssignmentProposition ameningitis = new AssignmentProposition(
                ExampleRV.MENINGITIS_RV, true);
            AssignmentProposition anotmeningitis = new AssignmentProposition(
                ExampleRV.MENINGITIS_RV, false);
            AssignmentProposition astiffNeck = new AssignmentProposition(
                ExampleRV.STIFF_NECK_RV, true);
            AssignmentProposition anotstiffNeck = new AssignmentProposition(
                ExampleRV.STIFF_NECK_RV, false);

            // P(stiffNeck | meningitis) = 0.7
            Assert.AreEqual(0.7, model.posterior(astiffNeck, ameningitis),
                            DELTA_THRESHOLD);
            // P(meningitis) = 1/50000
            Assert.AreEqual(0.00002, model.prior(ameningitis), DELTA_THRESHOLD);
            // P(~meningitis) = 1-1/50000
            Assert.AreEqual(0.99998, model.prior(anotmeningitis),
                            DELTA_THRESHOLD);
            // P(stiffNeck) = 0.01
            Assert.AreEqual(0.01, model.prior(astiffNeck), DELTA_THRESHOLD);
            // P(~stiffNeck) = 0.99
            Assert.AreEqual(0.99, model.prior(anotstiffNeck), DELTA_THRESHOLD);
            // P(meningitis | stiffneck)
            // = P(stiffneck | meningitis)P(meningitis)/P(stiffneck)
            // = (0.7 * 0.00002)/0.01
            // = 0.0014 (13.4)
            Assert.AreEqual(0.0014, model.posterior(ameningitis, astiffNeck),
                            DELTA_THRESHOLD);

            // Assuming P(~stiffneck | meningitis) = 0.3 (pg. 497), i.e. CPT (row
            // must = 1)
            //
            // P(meningitis | ~stiffneck)
            // = P(~stiffneck | meningitis)P(meningitis)/P(~stiffneck)
            // = (0.3 * 0.00002)/0.99
            // = 0.000006060606
            Assert.AreEqual(0.000006060606,
                            model.posterior(ameningitis, anotstiffNeck), DELTA_THRESHOLD);
        }