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RealSchur: Use PlanarRotation in "found two real eigenvalues" branch.

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This commit is contained in:
Jitse Niesen 2010-04-06 15:12:21 +01:00
parent d88d1cfa62
commit dad50338b8
1 changed files with 5 additions and 31 deletions
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36
Eigen/src/Eigenvalues/RealSchur.h
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@ -186,37 +186,11 @@ void RealSchur<MatrixType>::hqr2()
m_eivalues.coeffRef(n-1) = ComplexScalar(x + z, 0.0); m_eivalues.coeffRef(n-1) = ComplexScalar(x + z, 0.0);
m_eivalues.coeffRef(n) = ComplexScalar(z!=0.0 ? x - w / z : m_eivalues.coeff(n-1).real(), 0.0); m_eivalues.coeffRef(n) = ComplexScalar(z!=0.0 ? x - w / z : m_eivalues.coeff(n-1).real(), 0.0);
x = m_matT.coeff(n,n-1); PlanarRotation<Scalar> rot;
s = ei_abs(x) + ei_abs(z); rot.makeGivens(z, m_matT.coeff(n, n-1));
p = x / s; m_matT.block(0, n-1, size, size-n+1).applyOnTheLeft(n-1, n, rot.adjoint());
q = z / s; m_matT.block(0, 0, n+1, size).applyOnTheRight(n-1, n, rot);
r = ei_sqrt(p * p+q * q); m_matU.applyOnTheRight(n-1, n, rot);
p = p / r;
q = q / r;
// Row modification
for (int j = n-1; j < size; ++j)
{
z = m_matT.coeff(n-1,j);
m_matT.coeffRef(n-1,j) = q * z + p * m_matT.coeff(n,j);
m_matT.coeffRef(n,j) = q * m_matT.coeff(n,j) - p * z;
}
// Column modification
for (int i = 0; i <= n; ++i)
{
z = m_matT.coeff(i,n-1);
m_matT.coeffRef(i,n-1) = q * z + p * m_matT.coeff(i,n);
m_matT.coeffRef(i,n) = q * m_matT.coeff(i,n) - p * z;
}
// Accumulate transformations
for (int i = low; i <= high; ++i)
{
z = m_matU.coeff(i,n-1);
m_matU.coeffRef(i,n-1) = q * z + p * m_matU.coeff(i,n);
m_matU.coeffRef(i,n) = q * m_matU.coeff(i,n) - p * z;
}
} }
else // Complex pair else // Complex pair
{ {