void precondition(SparseMatrixTypeT const & A,
std::vector< std::map<SizeT, NumericT> > & output,
ilut_tag const & tag)
{
typedef std::map<SizeT, NumericT> SparseVector;
typedef typename SparseVector::iterator SparseVectorIterator;
typedef typename std::map<SizeT, NumericT>::const_iterator OutputRowConstIterator;
typedef std::multimap<NumericT, std::pair<SizeT, NumericT> > TemporarySortMap;
assert(viennacl::traits::size1(A) == output.size() && bool("Output matrix size mismatch") );
SparseVector w;
TemporarySortMap temp_map;
for (SizeT i=0; i<viennacl::traits::size1(A); ++i) // Line 1
{
/* if (i%10 == 0)
std::cout << i << std::endl;*/
//line 2: set up w
NumericT row_norm = setup_w(A, i, w);
NumericT tau_i = static_cast<NumericT>(tag.get_drop_tolerance()) * row_norm;
//line 3:
for (SparseVectorIterator w_k = w.begin(); w_k != w.end(); ++w_k)
{
SizeT k = w_k->first;
if (k >= i)
break;
//line 4:
NumericT a_kk = output[k][k];
if (a_kk <= 0 && a_kk >= 0) // a_kk == 0
{
std::cerr << "ViennaCL: FATAL ERROR in ILUT(): Diagonal entry is zero in row " << k
<< " while processing line " << i << "!" << std::endl;
throw "ILUT zero diagonal!";
}
NumericT w_k_entry = w_k->second / a_kk;
w_k->second = w_k_entry;
//line 5: (dropping rule to w_k)
if ( std::fabs(w_k_entry) > tau_i)
{
//line 7:
for (OutputRowConstIterator u_k = output[k].begin(); u_k != output[k].end(); ++u_k)
{
if (u_k->first > k)
w[u_k->first] -= w_k_entry * u_k->second;
}
}
//else
// w.erase(k);
} //for w_k
//Line 10: Apply a dropping rule to w
//Sort entries which are kept
temp_map.clear();
for (SparseVectorIterator w_k = w.begin(); w_k != w.end(); ++w_k)
{
SizeT k = w_k->first;
NumericT w_k_entry = w_k->second;
NumericT abs_w_k = std::fabs(w_k_entry);
if ( (abs_w_k > tau_i) || (k == i) )//do not drop diagonal element!
{
if (abs_w_k <= 0) // this can only happen for diagonal entry
throw "Triangular factor in ILUT singular!";
temp_map.insert(std::make_pair(abs_w_k, std::make_pair(k, w_k_entry)));
}
}
//Lines 10-12: write the largest p values to L and U
SizeT written_L = 0;
SizeT written_U = 0;
for (typename TemporarySortMap::reverse_iterator iter = temp_map.rbegin(); iter != temp_map.rend(); ++iter)
{
std::map<SizeT, NumericT> & row_i = output[i];
SizeT j = (iter->second).first;
NumericT w_j_entry = (iter->second).second;
if (j < i) // Line 11: entry for L
{
if (written_L < tag.get_entries_per_row())
{
row_i[j] = w_j_entry;
++written_L;
}
}
else if (j == i) // Diagonal entry is always kept
{
row_i[j] = w_j_entry;
}
else //Line 12: entry for U
{
if (written_U < tag.get_entries_per_row())
{
row_i[j] = w_j_entry;
++written_U;
}
}
}
w.clear(); //Line 13
} //for i
}
void GPHIKRawClassifier::classify ( const NICE::SparseVector * _xstar,
uint & _result,
SparseVector & _scores
) const
{
if ( ! this->b_isTrained )
fthrow(Exception, "Classifier not trained yet -- aborting!" );
_scores.clear();
// classification with quantization of test inputs
if ( this->q != NULL )
{
uint maxClassNo = 0;
for ( std::map< uint, double * >::const_iterator itT = this->precomputedT.begin() ;
itT != this->precomputedT.end();
itT++
)
{
uint classno = itT->first;
maxClassNo = std::max ( maxClassNo, classno );
double beta = 0;
double *T = itT->second;
for (SparseVector::const_iterator i = _xstar->begin(); i != _xstar->end(); i++ )
{
uint dim = i->first;
double v = i->second;
uint qBin = this->q->quantize( v, dim );
beta += T[dim * this->q->getNumberOfBins() + qBin];
}//for-loop over dimensions of test input
_scores[ classno ] = beta;
}//for-loop over 1-vs-all models
}
// classification with exact test inputs, i.e., no quantization involved
else
{
uint maxClassNo = 0;
for ( std::map<uint, PrecomputedType>::const_iterator i = this->precomputedA.begin() ; i != this->precomputedA.end(); i++ )
{
uint classno = i->first;
maxClassNo = std::max ( maxClassNo, classno );
double beta = 0;
GMHIKernelRaw::sparseVectorElement **dataMatrix = this->gm->getDataMatrix();
const PrecomputedType & A = i->second;
std::map<uint, PrecomputedType>::const_iterator j = this->precomputedB.find ( classno );
const PrecomputedType & B = j->second;
for (SparseVector::const_iterator i = _xstar->begin(); i != _xstar->end(); i++)
{
uint dim = i->first;
double fval = i->second;
uint nnz = this->nnz_per_dimension[dim];
uint nz = this->num_examples - nnz;
if ( nnz == 0 ) continue;
// useful
//if ( fval < this->f_tolerance ) continue;
uint position = 0;
//this->X_sorted.findFirstLargerInDimension(dim, fval, position);
GMHIKernelRaw::sparseVectorElement fval_element;
fval_element.value = fval;
//std::cerr << "value to search for " << fval << endl;
//std::cerr << "data matrix in dimension " << dim << endl;
//for (int j = 0; j < nnz; j++)
// std::cerr << dataMatrix[dim][j].value << std::endl;
GMHIKernelRaw::sparseVectorElement *it = upper_bound ( dataMatrix[dim], dataMatrix[dim] + nnz, fval_element );
position = distance ( dataMatrix[dim], it );
// /*// add zero elements
// if ( fval_element.value > 0.0 )
// position += nz;*/
bool posIsZero ( position == 0 );
// special case 1:
// new example is smaller than all known examples
// -> resulting value = fval * sum_l=1^n alpha_l
if ( position == 0 )
{
beta += fval * B[ dim ][ nnz - 1 ];
}
// special case 2:
// new example is equal to or larger than the largest training example in this dimension
// -> the term B[ dim ][ nnz-1 ] - B[ dim ][ indexElem ] is equal to zero and vanishes, which is logical, since all elements are smaller than the remaining prototypes!
else if ( position == nnz )
{
beta += A[ dim ][ nnz - 1 ];
}
// standard case: new example is larger then the smallest element, but smaller then the largest one in the corrent dimension
else
{
beta += A[ dim ][ position - 1 ] + fval * ( B[ dim ][ nnz - 1 ] - B[ dim ][ position - 1 ] );
}
// // correct upper bound to correct position, only possible if new example is not the smallest value in this dimension
// if ( !posIsZero )
// position--;
//
//
// double firstPart = 0.0;
// if ( !posIsZero )
// firstPart = ( A[ dim ][ position ] );
//
// double secondPart( B[ dim ][ this->num_examples-1-nz ]);
// if ( !posIsZero && (position >= nz) )
// secondPart -= B[dim][ position ];
//
// // but apply using the transformed one
// beta += firstPart + secondPart* fval;
}//for-loop over dimensions of test input
_scores[ classno ] = beta;
}//for-loop over 1-vs-all models
} // if-condition wrt quantization
_scores.setDim ( *this->knownClasses.rbegin() + 1 );
if ( this->knownClasses.size() > 2 )
{ // multi-class classification
_result = _scores.maxElement();
}
else if ( this->knownClasses.size() == 2 ) // binary setting
{
uint class1 = *(this->knownClasses.begin());
uint class2 = *(this->knownClasses.rbegin());
// since we erased the binary label vector corresponding to the smaller class number,
// we only have scores for the larger class number
uint class_for_which_we_have_a_score = class2;
uint class_for_which_we_dont_have_a_score = class1;
_scores[class_for_which_we_dont_have_a_score] = - _scores[class_for_which_we_have_a_score];
_result = _scores[class_for_which_we_have_a_score] > 0.0 ? class_for_which_we_have_a_score : class_for_which_we_dont_have_a_score;
}
}
