Tutorials > Tutorial 8: Hybrid model

// tutorial8.cpp

// 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.

#include "smile.h"

#include <cstdio>

static int CreateCptNode(

DSL_network& net, const char* id, const char* name,

std::initializer_list<const char*> outcomes, int xPos, int yPos);

static void UpdateAndShowStats(DSL_network &net);

int Tutorial8()

{

printf("Starting Tutorial8...\n");

DSL_errorH().RedirectToFile(stdout);

DSL_network net;

int res = net.ReadFile("tutorial7.xdsl");

if (DSL_OKAY != res)

{

printf(

"Network load failed, did you run Tutorial7 before Tutorial8?\n");

return res;

}

int toa = net.FindNode("toa");

if (toa < 0)

{

printf("Outside air temperature node not found.\n");

return toa;

}

CreateCptNode(net,

"zone", "Climate Zone", { "Temperate", "Desert" },

60, 20);

auto eq = net.GetNode(toa)->Def<DSL_equation>();

eq->SetEquation("toa=If(zone=\"Desert\",Normal(22,5),Normal(11,10))");

int perceived = CreateCptNode(net,

"perceived", "Perceived Temperature", { "Hot", "Warm", "Cold" },

60, 300);

net.AddArc(toa, perceived);

res = net.GetNode(perceived)->Def()->SetDefinition({

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)

});

if (DSL_OKAY != res)

{

return res;

}

net.GetNode("zone")->Val()->SetEvidence("Temperate");

printf("Results in temperate zone:\n");

UpdateAndShowStats(net);

net.GetNode("zone")->Val()->SetEvidence("Desert");

printf("Results in desert zone:\n");

UpdateAndShowStats(net);

res = net.WriteFile("tutorial8.xdsl");

if (DSL_OKAY != res)

{

return res;

}

printf("Tutorial8 complete: Network written to tutorial8.xdsl\n");

return DSL_OKAY;

}

static void ShowStats(DSL_network& net, int nodeHandle)

{

DSL_node* node = net.GetNode(nodeHandle);

const char* nodeId = node->GetId();

auto eqVal = node->Val<DSL_equationEvaluation>();

if (eqVal->IsEvidence())

{

double v;

eqVal->GetEvidence(v);

printf("%s has evidence set (%g)\n", nodeId, v);

return;

}

const DSL_Dmatrix& discBeliefs = eqVal->GetDiscBeliefs();

if (discBeliefs.IsEmpty())

{

double mean, stddev, vmin, vmax;

eqVal->GetStats(mean, stddev, vmin, vmax);

printf("%s: mean=%g stddev=%g min=%g max=%g\n",

nodeId, mean, stddev, vmin, vmax);

}

else

{

auto eqDef = node->Def<DSL_equation>();

const DSL_equation::IntervalVector& iv = eqDef->GetDiscIntervals();

printf("%s is discretized.\n", nodeId);

double loBound, hiBound;

eqDef->GetBounds(loBound, hiBound);

double lo = loBound;

for (int i = 0; i < discBeliefs.GetSize(); i++)

{

double hi = iv[i].second;

printf("\tP(%s in %g..%g)=%g\n", nodeId, lo, hi, discBeliefs[i]);

lo = hi;

}

static void UpdateAndShowStats(DSL_network &net)

{

net.UpdateBeliefs();

for (int h = net.GetFirstNode(); h >= 0; h = net.GetNextNode(h))

{

if (net.GetNode(h)->Def()->GetType() == DSL_EQUATION)

{

ShowStats(net, h);

}

static int CreateCptNode(

DSL_network& net, const char* id, const char* name,

std::initializer_list<const char*> outcomes, int xPos, int yPos)

{

int handle = net.AddNode(DSL_CPT, id);

DSL_node* node = net.GetNode(handle);

node->SetName(name);

node->Def()->SetNumberOfOutcomes(outcomes);

DSL_rectangle& position = node->Info().Screen().position;

position.center_X = xPos;

position.center_Y = yPos;

position.width = 85;

position.height = 55;

return handle;

}