GitHub-Proxy/eigen
1
0
Fork 0
mirror of https://gitlab.com/libeigen/eigen.git synced 2025-05-07 03:39:04 +08:00
Code Issues Packages Projects Releases Wiki Activity

RealSchur: reduce scope of temporary variables in hqr2().

Browse Source
This commit is contained in:
Jitse Niesen 2010-04-06 15:26:09 +01:00
parent dad50338b8
commit 86df74c765
1 changed files with 14 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
Eigen/src/Eigenvalues/RealSchur.h
View File

@ -129,7 +129,7 @@ void RealSchur<MatrixType>::hqr2()
const int low = 0;
const int high = size-1;
Scalar exshift = 0.0;
Scalar p=0,q=0,r=0,s=0,z=0,w,x,y;
Scalar p=0, q=0, r=0;
// Compute matrix norm
// FIXME to be efficient the following would requires a triangular reduxion code
@ -148,7 +148,7 @@ void RealSchur<MatrixType>::hqr2()
int l = n;
while (l > low)
{
s = ei_abs(m_matT.coeff(l-1,l-1)) + ei_abs(m_matT.coeff(l,l));
Scalar s = ei_abs(m_matT.coeff(l-1,l-1)) + ei_abs(m_matT.coeff(l,l));
if (s == 0.0)
s = norm;
if (ei_abs(m_matT.coeff(l,l-1)) < NumTraits<Scalar>::epsilon() * s)
@ -167,13 +167,13 @@ void RealSchur<MatrixType>::hqr2()
}
else if (l == n-1) // Two roots found
{
w = m_matT.coeff(n,n-1) * m_matT.coeff(n-1,n);
Scalar w = m_matT.coeff(n,n-1) * m_matT.coeff(n-1,n);
p = (m_matT.coeff(n-1,n-1) - m_matT.coeff(n,n)) * Scalar(0.5);
q = p * p + w;
z = ei_sqrt(ei_abs(q));
Scalar z = ei_sqrt(ei_abs(q));
m_matT.coeffRef(n,n) = m_matT.coeff(n,n) + exshift;
m_matT.coeffRef(n-1,n-1) = m_matT.coeff(n-1,n-1) + exshift;
x = m_matT.coeff(n,n);
Scalar x = m_matT.coeff(n,n);
// Scalar pair
if (q >= 0)
@ -203,9 +203,9 @@ void RealSchur<MatrixType>::hqr2()
else // No convergence yet
{
// Form shift
x = m_matT.coeff(n,n);
y = 0.0;
w = 0.0;
Scalar x = m_matT.coeff(n,n);
Scalar y = 0.0;
Scalar w = 0.0;
if (l < n)
{
y = m_matT.coeff(n-1,n-1);
@ -218,7 +218,7 @@ void RealSchur<MatrixType>::hqr2()
exshift += x;
for (int i = low; i <= n; ++i)
m_matT.coeffRef(i,i) -= x;
s = ei_abs(m_matT.coeff(n,n-1)) + ei_abs(m_matT.coeff(n-1,n-2));
Scalar s = ei_abs(m_matT.coeff(n,n-1)) + ei_abs(m_matT.coeff(n-1,n-2));
x = y = Scalar(0.75) * s;
w = Scalar(-0.4375) * s * s;
}
@ -226,7 +226,7 @@ void RealSchur<MatrixType>::hqr2()
// MATLAB's new ad hoc shift
if (iter == 30)
{
s = Scalar((y - x) / 2.0);
Scalar s = Scalar((y - x) / 2.0);
s = s * s + w;
if (s > 0)
{
@ -247,9 +247,9 @@ void RealSchur<MatrixType>::hqr2()
int m = n-2;
while (m >= l)
{
z = m_matT.coeff(m,m);
Scalar z = m_matT.coeff(m,m);
r = x - z;
s = y - z;
Scalar s = y - z;
p = (r * s - w) / m_matT.coeff(m+1,m) + m_matT.coeff(m,m+1);
q = m_matT.coeff(m+1,m+1) - z - r - s;
r = m_matT.coeff(m+2,m+1);
@ -296,7 +296,7 @@ void RealSchur<MatrixType>::hqr2()
if (x == 0.0)
break;
s = ei_sqrt(p * p + q * q + r * r);
Scalar s = ei_sqrt(p * p + q * q + r * r);
if (p < 0)
s = -s;
@ -311,7 +311,7 @@ void RealSchur<MatrixType>::hqr2()
p = p + s;
x = p / s;
y = q / s;
z = r / s;
Scalar z = r / s;
q = q / p;
r = r / p;