Eigen::internal::householder_qr_inplace_blocked< MatrixQR, HCoeffs, MatrixQRScalar, InnerStrideIsOne > Struct Template Reference

#include <HouseholderQR.h>

Static Public Member Functions
static void	run (MatrixQR &mat, HCoeffs &hCoeffs, Index maxBlockSize=32, typename MatrixQR::Scalar *tempData=0)

Detailed Description

template<typename MatrixQR, typename HCoeffs, typename MatrixQRScalar = typename MatrixQR::Scalar, bool InnerStrideIsOne = (MatrixQR::InnerStrideAtCompileTime == 1 && HCoeffs::InnerStrideAtCompileTime == 1)>
struct Eigen::internal::householder_qr_inplace_blocked< MatrixQR, HCoeffs, MatrixQRScalar, InnerStrideIsOne >

Member Function Documentation

run()

template<typename MatrixQR , typename HCoeffs , typename MatrixQRScalar = typename MatrixQR::Scalar, bool InnerStrideIsOne = (MatrixQR::InnerStrideAtCompileTime == 1 && HCoeffs::InnerStrideAtCompileTime == 1)>

static void Eigen::internal::householder_qr_inplace_blocked< MatrixQR, HCoeffs, MatrixQRScalar, InnerStrideIsOne >::run ( MatrixQR &  mat, HCoeffs &  hCoeffs, Index  maxBlockSize = 32, typename MatrixQR::Scalar *  tempData = 0  )

inlinestatic

                                                                                                                   {
    typedef typename MatrixQR::Scalar Scalar;
    typedef Block<MatrixQR, Dynamic, Dynamic> BlockType;
 
    Index rows = mat.rows();
    Index cols = mat.cols();
    Index size = (std::min)(rows, cols);
 
    typedef Matrix<Scalar, Dynamic, 1, ColMajor, MatrixQR::MaxColsAtCompileTime, 1> TempType;
    TempType tempVector;
    if (tempData == 0) {
      tempVector.resize(cols);
      tempData = tempVector.data();
    }
 
    Index blockSize = (std::min)(maxBlockSize, size);
 
    Index k = 0;
    for (k = 0; k < size; k += blockSize) {
      Index bs = (std::min)(size - k, blockSize);  // actual size of the block
      Index tcols = cols - k - bs;                 // trailing columns
      Index brows = rows - k;                      // rows of the block
 
      // partition the matrix:
      //        A00 | A01 | A02
      // mat  = A10 | A11 | A12
      //        A20 | A21 | A22
      // and performs the qr dec of [A11^T A12^T]^T
      // and update [A21^T A22^T]^T using level 3 operations.
      // Finally, the algorithm continue on A22
 
      BlockType A11_21 = mat.block(k, k, brows, bs);
      Block<HCoeffs, Dynamic, 1> hCoeffsSegment = hCoeffs.segment(k, bs);
 
      householder_qr_inplace_unblocked(A11_21, hCoeffsSegment, tempData);
 
      if (tcols) {
        BlockType A21_22 = mat.block(k, k + bs, brows, tcols);
        apply_block_householder_on_the_left(A21_22, A11_21, hCoeffsSegment, false);  // false == backward
      }
    }
  }

References Eigen::internal::apply_block_householder_on_the_left(), Eigen::HouseholderQR< MatrixType_ >::cols(), Eigen::SparseMatrix< Scalar_, Options_, StorageIndex_ >::cols(), Eigen::HouseholderQR< MatrixType_ >::hCoeffs(), Eigen::internal::householder_qr_inplace_unblocked(), k, min, Eigen::PlainObjectBase< Derived >::resize(), Eigen::HouseholderQR< MatrixType_ >::rows(), Eigen::SparseMatrix< Scalar_, Options_, StorageIndex_ >::rows(), and Eigen::EigenBase< Derived >::size().

Referenced by Eigen::HouseholderQR< MatrixType_ >::computeInPlace().

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The documentation for this struct was generated from the following file:

• HouseholderQR.h