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import pysmile

 

# Tutorial8 loads continuous model from the XDSL file written by Tutorial7,

# then adds discrete nodes to create a hybrid model. Inference is performed

# and model is saved to disk.

 

class Tutorial8:

    def __init__(self):

        print("Starting Tutorial8...")

        net = pysmile.Network()

 

        net.read_file("tutorial7.xdsl")

 

        self.create_cpt_node(net,

            "zone", "Climate Zone",

            ["Temperate", "Desert" ],

            60, 20)

        toa_handle = net.get_node("toa")

        net.set_node_equation("toa", 'toa=If(zone="Desert",Normal(22,5),Normal(11,10))')

 

        perceived_handle = self.create_cpt_node(net,

            "perceived", "Perceived Temperature",

            ["Hot", "Warm", "Cold"],

            60, 300)

        

        net.add_arc(toa_handle, perceived_handle)

 

        perceived_probs = [

            0,    # P(perceived=Hot |toa in -10..0)

            0.02, # P(perceived=Warm|toa in -10..0)

            0.98, # P(perceived=Cold|toa in -10..0)

            0.05, # P(perceived=Hot |toa in 0..10)

            0.15, # P(perceived=Warm|toa in 0..10)

            0.80, # P(perceived=Cold|toa in 0..10)

            0.10, # P(perceived=Hot |toa in 10..20)

            0.80, # P(perceived=Warm|toa in 10..20)

            0.10, # P(perceived=Cold|toa in 10..20)

            0.80, # P(perceived=Hot |toa in 20..30)

            0.15, # P(perceived=Warm|toa in 20..30)

            0.05, # P(perceived=Cold|toa in 20..30)

            0.98, # P(perceived=Hot |toa in 30..40)

            0.02, # P(perceived=Warm|toa in 30..40)

            0     # P(perceived=Cold|toa in 30..40)

        ]

 

        net.set_node_definition(perceived_handle, perceived_probs)

 

        net.set_evidence("zone", "Temperate")

        print("Results in temperate zone:")

        self.update_and_show_stats(net)

 

        net.set_evidence("zone", "Desert")

        print("Results in desert zone:")

        self.update_and_show_stats(net)

 

        net.write_file("tutorial8.xdsl")

        print("Tutorial8 complete: Network written to tutorial8.xdsl")

 

    def show_stats(self, net, node_handle):

        node_id = net.get_node_id(node_handle)

 

        if net.is_evidence(node_handle):

            v = net.get_cont_evidence(node_handle)

            print(f"{node_id} has evidence set: {v}")

            return

 

        if net.is_value_discretized(node_handle):

            print(node_id + " is discretized.")

            iv = net.get_node_equation_discretization(node_handle)

            bounds = net.get_node_equation_bounds(node_handle)

            disc_beliefs = net.get_node_value(node_handle)

            lo = bounds[0]

            for i in range(0, len(disc_beliefs)):

                hi = iv[i].boundary

                print(f"\tP({node_id} in {lo}..{hi})={disc_beliefs[i]}")

                lo = hi

        else:

            stats = net.get_node_sample_stats(node_handle)

            print(f"{node_id}: mean={stats[0]} stddev={stats[1]} min={stats[2]} max={stats[3]}")

 

    def update_and_show_stats(self, net):

        net.update_beliefs()

        for h in net.get_all_nodes():

            if net.get_node_type(h) == pysmile.NodeType.EQUATION:

                self.show_stats(net, h)

        print()

 

    def create_cpt_node(self, net, id, name, outcomes, x_pos, y_pos):

        handle = net.add_node(pysmile.NodeType.CPT, id)

        

        net.set_node_name(handle, name)

        net.set_node_position(handle, x_pos, y_pos, 85, 55)

        

        initial_outcome_count = net.get_outcome_count(handle)

        

        for i in range(0, initial_outcome_count):

            net.set_outcome_id(handle, i, outcomes[i])

        

        for i in range(initial_outcome_count, len(outcomes)):

            net.add_outcome(handle, outcomes[i])

            

        return handle