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* QR: add a rank() method and improve the accuracy of the rank

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* computation
* Array: add a count() method and rename AllAndAny.h file to
  BooleanRedux.h
This commit is contained in:
Gael Guennebaud
2009-01-20 16:37:52 +00:00
parent 81cb887baf
commit 8973d12cda
5 changed files with 39 additions and 5 deletions
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24
Eigen/src/QR/QR.h
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@@ -57,7 +57,9 @@ template<typename MatrixType> class QR
}
/** \returns whether or not the matrix is of full rank */
bool isFullRank() const { return !ei_isMuchSmallerThan(m_qr.diagonal().cwise().abs().minCoeff(), Scalar(1)); }
bool isFullRank() const { return rank() == std::min(m_qr.rows(),m_qr.cols()); }
int rank() const;
/** \returns a read-only expression of the matrix R of the actual the QR decomposition */
const Part<NestByValue<MatrixRBlockType>, UpperTriangular>
@@ -76,13 +78,33 @@ template<typename MatrixType> class QR
protected:
MatrixType m_qr;
VectorType m_hCoeffs;
mutable int m_rank;
mutable bool m_rankIsUptodate;
};
/** \returns the rank of the matrix of which *this is the QR decomposition. */
template<typename MatrixType>
int QR<MatrixType>::rank() const
{
if (!m_rankIsUptodate)
{
RealScalar maxCoeff = m_qr.diagonal().maxCoeff();
int n = std::min(m_qr.rows(),m_qr.cols());
m_rank = n;
for (int i=0; i<n; ++i)
if (ei_isMuchSmallerThan(m_qr.diagonal().coeff(i), maxCoeff))
--m_rank;
m_rankIsUptodate = true;
}
return m_rank;
}
#ifndef EIGEN_HIDE_HEAVY_CODE
template<typename MatrixType>
void QR<MatrixType>::_compute(const MatrixType& matrix)
{
m_rankIsUptodate = false;
m_qr = matrix;
int rows = matrix.rows();
int cols = matrix.cols();