92 lines
3.0 KiB
C++
92 lines
3.0 KiB
C++
// Copyright 2004, Ondra Kamenik
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#include <memory>
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#include "normal_moments.hh"
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#include "permutation.hh"
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#include "kron_prod.hh"
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#include "tl_static.hh"
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UNormalMoments::UNormalMoments(int maxdim, const TwoDMatrix &v)
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: TensorContainer<URSingleTensor>(1)
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{
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if (maxdim >= 2)
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generateMoments(maxdim, v);
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}
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/* Here we fill up the container with the tensors for d=2,4,6,… up to the given
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dimension. Each tensor of moments is equal to Fₙ(⊗ⁿv). This has a dimension
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equal to 2n. See the header file for proof and details.
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Here we sequentially construct the Kronecker power ⊗ⁿv and apply Fₙ.
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*/
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void
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UNormalMoments::generateMoments(int maxdim, const TwoDMatrix &v)
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{
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TL_RAISE_IF(v.nrows() != v.ncols(),
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"Variance-covariance matrix is not square in UNormalMoments constructor");
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int nv = v.nrows();
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auto mom2 = std::make_unique<URSingleTensor>(nv, 2);
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mom2->getData() = v.getData();
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insert(std::move(mom2));
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auto kronv = std::make_unique<URSingleTensor>(nv, 2);
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kronv->getData() = v.getData();
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for (int d = 4; d <= maxdim; d += 2)
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{
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auto newkronv = std::make_unique<URSingleTensor>(nv, d);
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KronProd::kronMult(ConstVector(v.getData()),
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ConstVector(kronv->getData()),
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newkronv->getData());
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kronv = std::move(newkronv);
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auto mom = std::make_unique<URSingleTensor>(nv, d);
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// apply Fₙ to ‘kronv’
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/* Here we go through all equivalences, select only those having 2
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elements in each class, then go through all elements in ‘kronv’ and
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add to permuted location of ‘mom’.
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The permutation must be taken as inverse of the permutation implied by
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the equivalence, since we need a permutation which after application
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to identity of indices yileds indices in the equivalence classes. Note
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how the Equivalence::apply() method works. */
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mom->zeros();
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const EquivalenceSet eset = TLStatic::getEquiv(d);
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for (const auto &cit : eset)
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if (selectEquiv(cit))
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{
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Permutation per(cit);
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per.inverse();
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for (Tensor::index it = kronv->begin(); it != kronv->end(); ++it)
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{
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IntSequence ind(kronv->dimen());
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per.apply(it.getCoor(), ind);
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Tensor::index it2(*mom, ind);
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mom->get(*it2, 0) += kronv->get(*it, 0);
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}
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}
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insert(std::move(mom));
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}
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}
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/* We return true for an equivalence whose each class has 2 elements. */
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bool
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UNormalMoments::selectEquiv(const Equivalence &e)
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{
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if (2*e.numClasses() != e.getN())
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return false;
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for (const auto &si : e)
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if (si.length() != 2)
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return false;
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return true;
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}
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/* Here we go through all the unfolded container, fold each tensor and
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insert it. */
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FNormalMoments::FNormalMoments(const UNormalMoments &moms)
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: TensorContainer<FRSingleTensor>(1)
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{
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for (const auto &mom : moms)
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insert(std::make_unique<FRSingleTensor>(*(mom.second)));
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}
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