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optimize sparse-sparse Kronecker product

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This commit is contained in:
Gael Guennebaud
2014-02-14 14:46:01 +01:00
parent 0d3f496233
commit 3283d98d13
2 changed files with 50 additions and 1 deletions
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17
unsupported/Eigen/src/KroneckerProduct/KroneckerTensorProduct.h
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@@ -153,7 +153,22 @@ void KroneckerProductSparse<Lhs,Rhs>::evalTo(Dest& dst) const
Bc = m_B.cols();
dst.resize(this->rows(), this->cols());
dst.resizeNonZeros(0);
dst.reserve(m_A.nonZeros() * m_B.nonZeros());
// compute number of non-zeros per innervectors of dst
{
VectorXi nnzA = VectorXi::Zero(Dest::IsRowMajor ? m_A.rows() : m_A.cols());
for (Index kA=0; kA < m_A.outerSize(); ++kA)
for (typename Lhs::InnerIterator itA(m_A,kA); itA; ++itA)
nnzA(Dest::IsRowMajor ? itA.row() : itA.col())++;
VectorXi nnzB = VectorXi::Zero(Dest::IsRowMajor ? m_B.rows() : m_B.cols());
for (Index kB=0; kB < m_B.outerSize(); ++kB)
for (typename Rhs::InnerIterator itB(m_B,kB); itB; ++itB)
nnzB(Dest::IsRowMajor ? itB.row() : itB.col())++;
Matrix<int,Dynamic,Dynamic,ColMajor> nnzAB = nnzB * nnzA.transpose();
dst.reserve(VectorXi::Map(nnzAB.data(), nnzAB.size()));
}
for (Index kA=0; kA < m_A.outerSize(); ++kA)
{