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import pysmile

 

# Tutorial5 loads the XDSL file created by Tutorial4,

# then performs the series of inference calls,

# changing evidence each time.

 

class Tutorial5:

    def __init__(self):

        print("Starting Tutorial5...")

        net = pysmile.Network()

        

        net.read_file("tutorial4.xdsl")

 

        print("No evidence set.")

        net.update_beliefs()

        self.print_financial_gain(net)

 

        print("Setting Forecast=Good.")

        self.change_evidence_and_update(net, "Forecast", "Good")

 

        print("Adding Economy=Up")

        self.change_evidence_and_update(net, "Economy", "Up")

        

        print("Tutorial5 complete.")        

 

    def change_evidence_and_update(self, net, node_id, outcome_id):

        if outcome_id is not None:

            net.set_evidence(node_id, outcome_id)        

        else:

            net.clear_evidence(node_id)

        

        net.update_beliefs()

        self.print_financial_gain(net)

 

    def print_financial_gain(self, net):

        expected_utility = net.get_node_value("Gain")

        util_parents = net.get_value_indexing_parents("Gain")

        self.print_gain_matrix(net, expected_utility, util_parents)

 

    def print_gain_matrix(self, net, mtx, parents):

        dim_count = 1 + len(parents)

        

        dim_sizes = [0] * dim_count

        for i in range(0, dim_count - 1):

            dim_sizes[i] = net.get_outcome_count(parents[i])

        dim_sizes[len(dim_sizes) - 1] = 1

        coords = [0] * dim_count

        for elem_idx in range(0, len(mtx)):

            self.index_to_coords(elem_idx, dim_sizes, coords)

            print("    Utility(", end="")

            if dim_count > 1:

                for parent_idx in range(0, len(parents)):

                    if parent_idx > 0:

                        print(",", end="")

                    parent_handle = parents[parent_idx]

                    print(f"{net.get_node_id(parent_handle)}=" 

                        + f"{net.get_outcome_id(parent_handle, coords[parent_idx])}", end="")

            print(f")={mtx[elem_idx]}")

        print()

 

    def index_to_coords(self, index, dim_sizes, coords):

        prod = 1

        for i in range(len(dim_sizes) - 1, -1, -1):

            coords[i] = int(index / prod) % dim_sizes[i]

            prod *= dim_sizes[i]