opencv/modules/ml/src/rtrees.cpp

430 lines
15 KiB
C++

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#include "precomp.hpp"
namespace cv {
namespace ml {
//////////////////////////////////////////////////////////////////////////////////////////
// Random trees //
//////////////////////////////////////////////////////////////////////////////////////////
RTrees::Params::Params()
: DTrees::Params(5, 10, 0.f, false, 10, 0, false, false, Mat())
{
calcVarImportance = false;
nactiveVars = 0;
termCrit = TermCriteria(TermCriteria::EPS + TermCriteria::COUNT, 50, 0.1);
}
RTrees::Params::Params( int _maxDepth, int _minSampleCount,
double _regressionAccuracy, bool _useSurrogates,
int _maxCategories, const Mat& _priors,
bool _calcVarImportance, int _nactiveVars,
TermCriteria _termCrit )
: DTrees::Params(_maxDepth, _minSampleCount, _regressionAccuracy, _useSurrogates,
_maxCategories, 0, false, false, _priors)
{
calcVarImportance = _calcVarImportance;
nactiveVars = _nactiveVars;
termCrit = _termCrit;
}
class DTreesImplForRTrees : public DTreesImpl
{
public:
DTreesImplForRTrees() {}
virtual ~DTreesImplForRTrees() {}
void setRParams(const RTrees::Params& p)
{
rparams = p;
}
RTrees::Params getRParams() const
{
return rparams;
}
void clear()
{
DTreesImpl::clear();
oobError = 0.;
rng = RNG(-1);
}
const vector<int>& getActiveVars()
{
int i, nvars = (int)allVars.size(), m = (int)activeVars.size();
for( i = 0; i < nvars; i++ )
{
int i1 = rng.uniform(0, nvars);
int i2 = rng.uniform(0, nvars);
std::swap(allVars[i1], allVars[i2]);
}
for( i = 0; i < m; i++ )
activeVars[i] = allVars[i];
return activeVars;
}
void startTraining( const Ptr<TrainData>& trainData, int flags )
{
DTreesImpl::startTraining(trainData, flags);
int nvars = w->data->getNVars();
int i, m = rparams.nactiveVars > 0 ? rparams.nactiveVars : cvRound(std::sqrt((double)nvars));
m = std::min(std::max(m, 1), nvars);
allVars.resize(nvars);
activeVars.resize(m);
for( i = 0; i < nvars; i++ )
allVars[i] = varIdx[i];
}
void endTraining()
{
DTreesImpl::endTraining();
vector<int> a, b;
std::swap(allVars, a);
std::swap(activeVars, b);
}
bool train( const Ptr<TrainData>& trainData, int flags )
{
Params dp(rparams.maxDepth, rparams.minSampleCount, rparams.regressionAccuracy,
rparams.useSurrogates, rparams.maxCategories, rparams.CVFolds,
rparams.use1SERule, rparams.truncatePrunedTree, rparams.priors);
setDParams(dp);
startTraining(trainData, flags);
int treeidx, ntrees = (rparams.termCrit.type & TermCriteria::COUNT) != 0 ?
rparams.termCrit.maxCount : 10000;
int i, j, k, vi, vi_, n = (int)w->sidx.size();
int nclasses = (int)classLabels.size();
double eps = (rparams.termCrit.type & TermCriteria::EPS) != 0 &&
rparams.termCrit.epsilon > 0 ? rparams.termCrit.epsilon : 0.;
vector<int> sidx(n);
vector<uchar> oobmask(n);
vector<int> oobidx;
vector<int> oobperm;
vector<double> oobres(n, 0.);
vector<int> oobcount(n, 0);
vector<int> oobvotes(n*nclasses, 0);
int nvars = w->data->getNVars();
int nallvars = w->data->getNAllVars();
const int* vidx = !varIdx.empty() ? &varIdx[0] : 0;
vector<float> samplebuf(nallvars);
Mat samples = w->data->getSamples();
float* psamples = samples.ptr<float>();
size_t sstep0 = samples.step1(), sstep1 = 1;
Mat sample0, sample(nallvars, 1, CV_32F, &samplebuf[0]);
int predictFlags = _isClassifier ? (PREDICT_MAX_VOTE + RAW_OUTPUT) : PREDICT_SUM;
bool calcOOBError = eps > 0 || rparams.calcVarImportance;
double max_response = 0.;
if( w->data->getLayout() == COL_SAMPLE )
std::swap(sstep0, sstep1);
if( !_isClassifier )
{
for( i = 0; i < n; i++ )
{
double val = std::abs(w->ord_responses[w->sidx[i]]);
max_response = std::max(max_response, val);
}
}
if( rparams.calcVarImportance )
varImportance.resize(nallvars, 0.f);
for( treeidx = 0; treeidx < ntrees; treeidx++ )
{
putchar('.'); fflush(stdout);
for( i = 0; i < n; i++ )
oobmask[i] = (uchar)1;
for( i = 0; i < n; i++ )
{
j = rng.uniform(0, n);
sidx[i] = w->sidx[j];
oobmask[j] = (uchar)0;
}
int root = addTree( sidx );
if( root < 0 )
return false;
if( calcOOBError )
{
oobidx.clear();
for( i = 0; i < n; i++ )
{
if( !oobmask[i] )
oobidx.push_back(i);
}
int n_oob = (int)oobidx.size();
// if there is no out-of-bag samples, we can not compute OOB error
// nor update the variable importance vector; so we proceed to the next tree
if( n_oob == 0 )
continue;
double ncorrect_responses = 0.;
oobError = 0.;
for( i = 0; i < n_oob; i++ )
{
j = oobidx[i];
sample = Mat( nallvars, 1, CV_32F, psamples + sstep0*w->sidx[j], sstep1*sizeof(psamples[0]) );
double val = predictTrees(Range(treeidx, treeidx+1), sample, predictFlags);
if( !_isClassifier )
{
oobres[j] += val;
oobcount[j]++;
double true_val = w->ord_responses[w->sidx[j]];
double a = oobres[j]/oobcount[j] - true_val;
oobError += a*a;
val = (val - true_val)/max_response;
ncorrect_responses += std::exp( -val*val );
}
else
{
int ival = cvRound(val);
int* votes = &oobvotes[j*nclasses];
votes[ival]++;
int best_class = 0;
for( k = 1; k < nclasses; k++ )
if( votes[best_class] < votes[k] )
best_class = k;
int diff = best_class != w->cat_responses[w->sidx[j]];
oobError += diff;
ncorrect_responses += diff == 0;
}
}
oobError /= n_oob;
if( rparams.calcVarImportance && n_oob > 1 )
{
oobperm.resize(n_oob);
for( i = 0; i < n_oob; i++ )
oobperm[i] = oobidx[i];
for( vi_ = 0; vi_ < nvars; vi_++ )
{
vi = vidx ? vidx[vi_] : vi_;
double ncorrect_responses_permuted = 0;
for( i = 0; i < n_oob; i++ )
{
int i1 = rng.uniform(0, n_oob);
int i2 = rng.uniform(0, n_oob);
std::swap(i1, i2);
}
for( i = 0; i < n_oob; i++ )
{
j = oobidx[i];
int vj = oobperm[i];
sample0 = Mat( nallvars, 1, CV_32F, psamples + sstep0*w->sidx[j], sstep1*sizeof(psamples[0]) );
for( k = 0; k < nallvars; k++ )
sample.at<float>(k) = sample0.at<float>(k);
sample.at<float>(vi) = psamples[sstep0*w->sidx[vj] + sstep1*vi];
double val = predictTrees(Range(treeidx, treeidx+1), sample, predictFlags);
if( !_isClassifier )
{
val = (val - w->ord_responses[w->sidx[j]])/max_response;
ncorrect_responses_permuted += exp( -val*val );
}
else
ncorrect_responses_permuted += cvRound(val) == w->cat_responses[w->sidx[j]];
}
varImportance[vi] += (float)(ncorrect_responses - ncorrect_responses_permuted);
}
}
}
if( calcOOBError && oobError < eps )
break;
}
printf("done!\n");
if( rparams.calcVarImportance )
{
for( vi_ = 0; vi_ < nallvars; vi_++ )
varImportance[vi_] = std::max(varImportance[vi_], 0.f);
normalize(varImportance, varImportance, 1., 0, NORM_L1);
}
endTraining();
return true;
}
void writeTrainingParams( FileStorage& fs ) const
{
DTreesImpl::writeTrainingParams(fs);
fs << "nactive_vars" << rparams.nactiveVars;
}
void write( FileStorage& fs ) const
{
if( roots.empty() )
CV_Error( CV_StsBadArg, "RTrees have not been trained" );
writeParams(fs);
fs << "oob_error" << oobError;
if( !varImportance.empty() )
fs << "var_importance" << varImportance;
int k, ntrees = (int)roots.size();
fs << "ntrees" << ntrees
<< "trees" << "[";
for( k = 0; k < ntrees; k++ )
{
fs << "{";
writeTree(fs, roots[k]);
fs << "}";
}
fs << "]";
}
void readParams( const FileNode& fn )
{
DTreesImpl::readParams(fn);
rparams.maxDepth = params0.maxDepth;
rparams.minSampleCount = params0.minSampleCount;
rparams.regressionAccuracy = params0.regressionAccuracy;
rparams.useSurrogates = params0.useSurrogates;
rparams.maxCategories = params0.maxCategories;
rparams.priors = params0.priors;
FileNode tparams_node = fn["training_params"];
rparams.nactiveVars = (int)tparams_node["nactive_vars"];
}
void read( const FileNode& fn )
{
clear();
//int nclasses = (int)fn["nclasses"];
//int nsamples = (int)fn["nsamples"];
oobError = (double)fn["oob_error"];
int ntrees = (int)fn["ntrees"];
fn["var_importance"] >> varImportance;
readParams(fn);
FileNode trees_node = fn["trees"];
FileNodeIterator it = trees_node.begin();
CV_Assert( ntrees == (int)trees_node.size() );
for( int treeidx = 0; treeidx < ntrees; treeidx++, ++it )
{
FileNode nfn = (*it)["nodes"];
readTree(nfn);
}
}
RTrees::Params rparams;
double oobError;
vector<float> varImportance;
vector<int> allVars, activeVars;
RNG rng;
};
class RTreesImpl : public RTrees
{
public:
RTreesImpl() {}
virtual ~RTreesImpl() {}
String getDefaultModelName() const { return "opencv_ml_rtrees"; }
bool train( const Ptr<TrainData>& trainData, int flags )
{
return impl.train(trainData, flags);
}
float predict( InputArray samples, OutputArray results, int flags ) const
{
return impl.predict(samples, results, flags);
}
void write( FileStorage& fs ) const
{
impl.write(fs);
}
void read( const FileNode& fn )
{
impl.read(fn);
}
void setRParams(const Params& p) { impl.setRParams(p); }
Params getRParams() const { return impl.getRParams(); }
Mat getVarImportance() const { return Mat_<float>(impl.varImportance, true); }
int getVarCount() const { return impl.getVarCount(); }
bool isTrained() const { return impl.isTrained(); }
bool isClassifier() const { return impl.isClassifier(); }
const vector<int>& getRoots() const { return impl.getRoots(); }
const vector<Node>& getNodes() const { return impl.getNodes(); }
const vector<Split>& getSplits() const { return impl.getSplits(); }
const vector<int>& getSubsets() const { return impl.getSubsets(); }
DTreesImplForRTrees impl;
};
Ptr<RTrees> RTrees::create(const Params& params)
{
Ptr<RTreesImpl> p = makePtr<RTreesImpl>();
p->setRParams(params);
return p;
}
}}
// End of file.