Function rotationTensor

src/OpenFOAM/primitives/transform/transform.H:46–77

- Rotational transformation tensor from vector n1 to n2

//- Rotational transformation tensor from vector n1 to n2
inline tensor rotationTensor
(
    const vector& n1,
    const vector& n2
)
{
    const scalar s = n1 & n2;
    const vector n3 = n1 ^ n2;
    const scalar magSqrN3 = magSqr(n3);

    // n1 and n2 define a plane n3
    if (magSqrN3 > SMALL)
    {
        // Return rotational transformation tensor in the n3-plane
        return
            s*I
          + (1 - s)*sqr(n3)/magSqrN3
          + (n2*n1 - n1*n2);
    }
    // n1 and n2 are contradirectional
    else if (s < 0)
    {
        // Return mirror transformation tensor
        return I + 2*n1*n2;
    }
    // n1 and n2 are codirectional
    else
    {
        // Return null transformation tensor
        return I;
    }
}


//- Rotational transformation tensor about the x-axis by omega radians