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// tutorial2.cpp
// Tutorial2 loads the XDSL file created by Tutorial1,
// then performs the series of inference calls,
// changing evidence each time.
#include "smile.h"
#include <cstdio>
static int ChangeEvidenceAndUpdate(
DSL_network &net, const char *nodeId, const char *outcomeId);
static void PrintAllPosteriors(DSL_network &net);
int Tutorial2()
{
printf("Starting Tutorial2...\n");
DSL_errorH().RedirectToFile(stdout);
// load the network created by Tutorial1
DSL_network net;
int res = net.ReadFile("tutorial1.xdsl");
if (DSL_OKAY != res)
{
printf(
"Network load failed, did you run Tutorial1 before Tutorial2?\n");
return res;
}
printf("Posteriors with no evidence set:\n");
net.UpdateBeliefs();
PrintAllPosteriors(net);
printf("\nSetting Forecast=Good.\n");
ChangeEvidenceAndUpdate(net, "Forecast", "Good");
printf("\nAdding Economy=Up.\n");
ChangeEvidenceAndUpdate(net, "Economy", "Up");
printf("\nChanging Forecast to Poor, keeping Economy=Up.\n");
ChangeEvidenceAndUpdate(net, "Forecast", "Poor");
printf("\nRemoving evidence from Economy, keeping Forecast=Poor.\n");
ChangeEvidenceAndUpdate(net, "Economy", NULL);
printf("\nTutorial2 complete.\n");
return DSL_OKAY;
}
static void PrintPosteriors(DSL_network &net, int handle)
{
DSL_node *node = net.GetNode(handle);
const char* nodeId = node->GetId();
const DSL_nodeVal* val = node->Val();
if (val->IsEvidence())
{
printf("%s has evidence set (%s)\n",
nodeId, val->GetEvidenceId());
}
else
{
const DSL_idArray& outcomeIds = *node->Def()->GetOutcomeIds();
const DSL_Dmatrix& posteriors = *val->GetMatrix();
for (int i = 0; i < posteriors.GetSize(); i++)
{
printf("P(%s=%s)=%g\n", nodeId, outcomeIds[i], posteriors[i]);
}
}
}
static void PrintAllPosteriors(DSL_network &net)
{
for (int h = net.GetFirstNode(); h >= 0; h = net.GetNextNode(h))
{
PrintPosteriors(net, h);
}
}
static int ChangeEvidenceAndUpdate(
DSL_network &net, const char *nodeId, const char *outcomeId)
{
DSL_node* node = net.GetNode(nodeId);
if (NULL == node)
{
return DSL_OUT_OF_RANGE;
}
int res;
if (NULL != outcomeId)
{
res = node->Val()->SetEvidence(outcomeId);
}
else
{
res = node->Val()->ClearEvidence();
}
if (DSL_OKAY != res)
{
return res;
}
res = net.UpdateBeliefs();
if (DSL_OKAY != res)
{
return res;
}
PrintAllPosteriors(net);
return DSL_OKAY;
}