On Nov 12, 2008, at 10:33 PM, Keren Lasker wrote:
> Daniel - the angles are not Euler angles but just three angles around > X/Y/Z axis. It is not entirely clear to me what the constructor does, but I suspect it is one of the things that gets called Euler rotations (but I haven't looked at Euler angles in a while). I think it needs to be made clearer whether the rotation is about the rotated or unrotated versions of the specified axis.
Why are we providing initialization from such a representation anyway? Is there some use for which they are better than quaternions?
> > Would you like the option to rotate around another axis, ,something > like: > (1,1,0),45 - meaning rotating around the diagonal of the XY plane in > 45 degrees? Yes, although radians are probably preferable. Basically a non- normalized quaternion.
> > On Nov 12, 2008, at 5:43 PM, Daniel Russel wrote: > >> I don't like having two equivalent constructors from thevsame data or >> using a vector to hold angles. >> >> What I had meant with my suggestion is initialization from an axis >> and >> an amount of rotation about that axis as that is a somewhat less >> problematic basis than Euler angles (and one I use :-) >> >> >> >> On Nov 12, 2008, at 2:31 PM, Notification of IMP commits <imp-commits@salilab.org >>> wrote: >> >>> Author: kerenl@SALILAB.ORG >>> Date: 2008-11-12 14:31:59 -0800 (Wed, 12 Nov 2008) >>> New Revision: 854 >>> >>> Modified: >>> trunk/modules/misc/include/Rotation3D.h >>> Log: >>> 1. Change protected to private >>> 2. Add constructors from Vector3D and an angle >>> 3. update documentation >>> >>> Modified: trunk/modules/misc/include/Rotation3D.h >>> =================================================================== >>> --- trunk/modules/misc/include/Rotation3D.h 2008-11-12 21:15:36 >>> UTC (rev 853) >>> +++ trunk/modules/misc/include/Rotation3D.h 2008-11-12 22:31:59 >>> UTC (rev 854) >>> @@ -19,26 +19,28 @@ >>> >>> class IMPMISCEXPORT Rotation3D { >>> public: >>> - //! Initialize a rotation in x-y-z order from three angles >>> + Rotation3D(){ >>> + } >>> + //! Initialize a rotation in x-y-z order from three Euler angles >>> /** \param[in] xr Rotation around the X axis >>> \param[in] yr Rotation around the Y axis >>> \param[in] zr Rotation around the Z axis >>> */ >>> Rotation3D(Float xr, Float yr, Float zr) { >>> - Float cx = cos(xr); Float cy = cos(yr); Float cz = cos(zr); >>> - Float sx = sin(xr); Float sy = sin(yr); Float sz = sin(zr); >>> - Float m00 = cz*cy; >>> - Float m11 = -sy*sx*sz + cx*cz; >>> - Float m22 = cy*cx; >>> - quat_[0] = sqrt(1+m00+m11+m22)/2.0; >>> - quat_[1] = sqrt(1+m00-m11-m22)/2.0; >>> - quat_[2] = sqrt(1-m00+m11-m22)/2.0; >>> - quat_[3] = sqrt(1-m00-m11+m22)/2.0; >>> - if (cy*sx + sy*cx*sz + sx*cz < 0.0) quat_[1] = -quat_[1]; >>> - if (sz*sx - sy*cx*cz - sy < 0.0) quat_[2] = -quat_[2]; >>> - if (sz*cy + sy*sx*cz + sz*cx < 0.0) quat_[3] = -quat_[3]; >>> + init_angles(xr,yr,zr); >>> } >>> - >>> + //! Initialize a rotation in x-y-z order from three identical >>> Euler angles >>> + /** \param[in] e_angle Rotation around first the X axis, Y axis >>> and Z axis >>> + */ >>> + Rotation3D(Float e_angle){ >>> + init_angles(e_angle, e_angle, e_angle); >>> + } >>> + //! Initialize a rotation in x-y-z order from three Euler angles >>> + /** \param[in] v A vector that holds three Euler angles (x-y-z >>> order) >>> + */ >>> + Rotation3D(const Vector3D &v){ >>> + init_angles(v[0],v[1],v[2]); >>> + } >>> Matrix3D get_matrix() const { >>> const Float a = quat_[0]; >>> const Float b = quat_[1]; >>> @@ -76,7 +78,22 @@ >>> return atan2(matrix21(), matrix11()); >>> } >>> >>> -protected: >>> +private: >>> + void init_angles(Float xr, Float yr, Float zr) { >>> + Float cx = cos(xr); Float cy = cos(yr); Float cz = cos(zr); >>> + Float sx = sin(xr); Float sy = sin(yr); Float sz = sin(zr); >>> + Float m00 = cz*cy; >>> + Float m11 = -sy*sx*sz + cx*cz; >>> + Float m22 = cy*cx; >>> + quat_[0] = sqrt(1+m00+m11+m22)/2.0; >>> + quat_[1] = sqrt(1+m00-m11-m22)/2.0; >>> + quat_[2] = sqrt(1-m00+m11-m22)/2.0; >>> + quat_[3] = sqrt(1-m00-m11+m22)/2.0; >>> + if (cy*sx + sy*cx*sz + sx*cz < 0.0) quat_[1] = -quat_[1]; >>> + if (sz*sx - sy*cx*cz - sy < 0.0) quat_[2] = -quat_[2]; >>> + if (sz*cy + sy*sx*cz + sz*cx < 0.0) quat_[3] = -quat_[3]; >>> + } >>> + >>> Float matrix11() const { >>> return sqr(quat_[0]) + sqr(quat_[1]) - sqr(quat_[2]) - >>> sqr(quat_[3]); >>> } >>> >>> _______________________________________________ >>> IMP-commits mailing list >>> IMP-commits@salilab.org >>> https://salilab.org/mailman/listinfo/imp-commits >> _______________________________________________ >> IMP-dev mailing list >> IMP-dev@salilab.org >> https://salilab.org/mailman/listinfo/imp-dev > > _______________________________________________ > IMP-dev mailing list > IMP-dev@salilab.org > https://salilab.org/mailman/listinfo/imp-dev