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ENH: Add rotation tensor constructor to quaternion class

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This commit is contained in:
laurence
2012-07-09 12:31:30 +01:00
parent 772be84dde
commit c030c5e40a
2 changed files with 78 additions and 0 deletions
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3
src/OpenFOAM/primitives/quaternion/quaternion.H
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@ -109,6 +109,9 @@ public:
const scalar angleZ
);
//- Construct a quaternion from a rotation tensor
inline explicit quaternion(const tensor& rotationTensor);
//- Construct from Istream
quaternion(Istream&);

75
src/OpenFOAM/primitives/quaternion/quaternionI.H
View File

@ -66,6 +66,81 @@ inline Foam::quaternion::quaternion
operator*=(quaternion(vector(0, 0, 1), angleZ));
}
inline Foam::quaternion::quaternion
(
const tensor& rotationTensor
)
{
scalar trace = rotationTensor.xx()
+ rotationTensor.yy()
+ rotationTensor.zz();
if (trace > 0)
{
scalar s = 0.5/Foam::sqrt(trace + 1.0);
w_ = 0.25/s;
v_[0] = (rotationTensor.zy() - rotationTensor.yz())*s;
v_[1] = (rotationTensor.xz() - rotationTensor.zx())*s;
v_[2] = (rotationTensor.yx() - rotationTensor.xy())*s;
}
else
{
if
(
rotationTensor.xx() > rotationTensor.yy()
&& rotationTensor.xx() > rotationTensor.zz()
)
{
scalar s = 2.0*Foam::sqrt
(
1.0
+ rotationTensor.xx()
- rotationTensor.yy()
- rotationTensor.zz()
);
w_ = (rotationTensor.zy() - rotationTensor.yz())/s;
v_[0] = 0.25*s;
v_[1] = (rotationTensor.xy() + rotationTensor.yx())/s;
v_[2] = (rotationTensor.xz() + rotationTensor.zx())/s;
}
else if
(
rotationTensor.yy() > rotationTensor.zz()
)
{
scalar s = 2.0*Foam::sqrt
(
1.0
+ rotationTensor.yy()
- rotationTensor.xx()
- rotationTensor.zz()
);
w_ = (rotationTensor.xz() - rotationTensor.xz())/s;
v_[0] = (rotationTensor.xy() + rotationTensor.yx())/s;
v_[1] = 0.25*s;
v_[2] = (rotationTensor.yz() + rotationTensor.zy())/s;
}
else
{
scalar s = 2.0*Foam::sqrt
(
1.0
+ rotationTensor.zz()
- rotationTensor.xx()
- rotationTensor.yy()
);
w_ = (rotationTensor.yx() - rotationTensor.xy())/s;
v_[0] = (rotationTensor.xz() + rotationTensor.zx())/s;
v_[1] = (rotationTensor.yz() + rotationTensor.zy())/s;
v_[2] = 0.25*s;
}
}
}
// * * * * * * * * * * * * * * * Member Functions * * * * * * * * * * * * * //