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improved per-component BSDF chi-square test

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Wenzel Jakob 2011-06-23 01:43:39 +02:00
parent 5a40118a44
commit a5364d02f1
3 changed files with 60 additions and 13 deletions
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2
include/mitsuba/core/chisquare.h
View File

@ -95,7 +95,7 @@ public:
ChiSquareTest(int thetaBins = 10, int phiBins = 0, size_t sampleCount = 0);
/// Set the log level
inline void setLogLevel(ELogLevel logLevel) { m_logLevel = EInfo; }
inline void setLogLevel(ELogLevel logLevel) { m_logLevel = logLevel; }
/**
* \brief Fill the actual and reference bin counts

6
src/libcore/chisquare.cpp
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@ -59,9 +59,9 @@ bool ChiSquareTest::runTest(int distParams, Float pvalThresh) {
Log(m_logLevel, "Pooled %i cells with an expected "
"number of < 5 entries!", pooledCells);
if (pooledRef < 5) {
Log(EWarn, "Even after pooling, the expected "
Log(EWarn, "Even after pooling %i cells, the expected "
"number of entries is < 5 (%f), expect badness!",
pooledRef);
pooledCells, pooledRef);
}
Float diff = pooledCounts - pooledRef;
chsq += (diff*diff) / pooledRef;
@ -78,7 +78,7 @@ bool ChiSquareTest::runTest(int distParams, Float pvalThresh) {
Log(m_logLevel, pval > 0.01 ? "P-value = %.4f" : "P-value = %e", pval);
if (pval < pvalThresh) {
Log(EWarn, "Rejecting the null hypothesis");
Log(EWarn, "Rejecting the null hypothesis (P-value=%e)", pval);
return false;
}
return true;

65
src/tests/test_chisquare.cpp
View File

@ -36,13 +36,14 @@ public:
class BSDFFunctor {
public:
BSDFFunctor(const BSDF *bsdf, Random *random, const Vector &wi)
: m_bsdf(bsdf), m_random(random), m_wi(wi) { }
BSDFFunctor(const BSDF *bsdf, Random *random, const Vector &wi, int component = -1)
: m_bsdf(bsdf), m_random(random), m_wi(wi), m_component(component) { }
std::pair<Vector, Float> generateSample() {
Point2 sample(m_random->nextFloat(), m_random->nextFloat());
Intersection its;
BSDFQueryRecord bRec(its);
bRec.component = m_component;
bRec.wi = m_wi;
m_bsdf->sample(bRec, sample);
@ -52,6 +53,7 @@ public:
Float pdf(const Vector &wo) const {
Intersection its;
BSDFQueryRecord bRec(its);
bRec.component = m_component;
bRec.wi = m_wi;
bRec.wo = wo;
return m_bsdf->pdf(bRec);
@ -60,6 +62,7 @@ public:
ref<const BSDF> m_bsdf;
ref<Random> m_random;
Vector m_wi;
int m_component;
};
void test01_BSDF() {
@ -67,17 +70,18 @@ public:
ref<Scene> scene = loadScene("data/tests/test_bsdf.xml");
const std::vector<ConfigurableObject *> objects = scene->getReferencedObjects();
size_t thetaBins = 10, wiSamples = 5;
size_t thetaBins = 10, wiSamples = 20, failureCount = 0, testCount = 0;
ref<Random> random = new Random();
Log(EInfo, "Verifying BSDF sampling routines ..");
for (size_t i=0; i<objects.size(); ++i) {
if (!objects[i]->getClass()->derivesFrom(MTS_CLASS(BSDF)))
continue;
const BSDF *bsdf = static_cast<const BSDF *>(objects[i]);
Log(EInfo, "Checking sampling with %i different incident directions, BSDF:\n%s",
wiSamples, bsdf->toString().c_str());
Log(EInfo, "Processing BSDF model %s", bsdf->toString().c_str());
Log(EInfo, "Checking the combined model for %i incident directions", wiSamples);
/* Test for a number of different incident directions */
for (size_t j=0; j<wiSamples; ++j) {
@ -90,6 +94,7 @@ public:
BSDFFunctor functor(bsdf, random, wi);
ref<ChiSquareTest> chiSqr = new ChiSquareTest(thetaBins);
chiSqr->setLogLevel(EDebug);
// Initialize the tables used by the chi-square test
chiSqr->fill(
@ -97,16 +102,58 @@ public:
boost::bind(&BSDFFunctor::pdf, functor, _1)
);
// (the folowing assumes that the distribution has 1 parameter, e.g. exponent value)
// (the following assumes that the distribution has 1 parameter, e.g. exponent value)
if (!chiSqr->runTest(1)) {
// Optional: dump the tables to a MATLAB file for external analysis
chiSqr->dumpTables("failure.m");
failAndContinue("Oh oh, the chi-square test failed! Dumped the contingency tables to 'failure.m'");
std::string filename = formatString("failure_%i.m", failureCount++);
chiSqr->dumpTables(filename);
failAndContinue(formatString("Uh oh, the chi-square test indicates a potential "
"issue for wi=%s. Dumped the contingency tables to '%s' for user analysis",
wi.toString().c_str(), filename.c_str()));
} else {
succeed();
}
++testCount;
}
if (bsdf->getComponentCount() > 1) {
for (int comp=0; comp<bsdf->getComponentCount(); ++comp) {
Log(EInfo, "Checking BSDF component %i", comp);
/* Test for a number of different incident directions */
for (size_t j=0; j<wiSamples; ++j) {
Vector wi;
if (bsdf->getType(comp) & (BSDF::EDiffuseTransmission | BSDF::EGlossyTransmission))
wi = squareToSphere(Point2(random->nextFloat(), random->nextFloat()));
else
wi = squareToHemispherePSA(Point2(random->nextFloat(), random->nextFloat()));
BSDFFunctor functor(bsdf, random, wi, comp);
ref<ChiSquareTest> chiSqr = new ChiSquareTest(thetaBins);
chiSqr->setLogLevel(EDebug);
// Initialize the tables used by the chi-square test
chiSqr->fill(
boost::bind(&BSDFFunctor::generateSample, functor),
boost::bind(&BSDFFunctor::pdf, functor, _1)
);
// (the following assumes that the distribution has 1 parameter, e.g. exponent value)
if (!chiSqr->runTest(1)) {
std::string filename = formatString("failure_%i.m", failureCount++);
chiSqr->dumpTables(filename);
failAndContinue(formatString("Uh oh, the chi-square test indicates a potential "
"issue for wi=%s. Dumped the contingency tables to '%s' for user analysis",
wi.toString().c_str(), filename.c_str()));
} else {
succeed();
}
++testCount;
}
}
}
}
Log(EInfo, "%i/%i BSDF checks succeeded", testCount-failureCount, testCount);
}
};