 05 Oct, 2018 1 commit


Mark Olesen authored
Previously the coordinate system functionality was split between coordinateSystem and coordinateRotation. The coordinateRotation stored the rotation tensor and handled all tensor transformations. The functionality has now been revised and consolidated into the coordinateSystem classes. The sole purpose of coordinateRotation is now just to provide a selectable mechanism of how to define the rotation tensor (eg, axisangle, euler angles, local axes) for user input, but after providing the appropriate rotation tensor it has no further influence on the transformations.  The coordinateSystem class now contains an origin and a base rotation tensor directly and various transformation methods.  The origin represents the "shift" for a local coordinate system.  The base rotation tensor represents the "tilt" or orientation of the local coordinate system in general (eg, for mapping positions), but may require positiondependent tensors when transforming vectors and tensors. For some coordinate systems (currently the cylindrical coordinate system), the rotation tensor required for rotating a vector or tensor is positiondependent. The new coordinateSystem and its derivates (cartesian, cylindrical, indirect) now provide a uniform() method to define if the rotation tensor is position dependent/independent. The coordinateSystem transform and invTransform methods are now available in twoparameter forms for obtaining positiondependent rotation tensors. Eg, ... = cs.transform(globalPt, someVector); In some cases it can be useful to use query uniform() to avoid storage of redundant values. if (cs.uniform()) { vector xx = cs.transform(someVector); } else { List<vector> xx = cs.transform(manyPoints, someVector); } Support transform/invTransform for common data types: (scalar, vector, sphericalTensor, symmTensor, tensor). ==================== Breaking Changes ====================  These changes to coordinate systems and rotations may represent a breaking change for existing user coding.  Relocating the rotation tensor into coordinateSystem itself means that the coordinate system 'R()' method now returns the rotation directly instead of the coordinateRotation. The method name 'R()' was chosen for consistency with other lowlevel entities (eg, quaternion). The following changes will be needed in coding: Old: tensor rot = cs.R().R(); New: tensor rot = cs.R(); Old: cs.R().transform(...); New: cs.transform(...); Accessing the runTime selectable coordinateRotation has moved to the rotation() method: Old: Info<< "Rotation input: " << cs.R() << nl; New: Info<< "Rotation input: " << cs.rotation() << nl;  Naming consistency changes may also cause code to break. Old: transformVector() New: transformPrincipal() The old method name transformTensor() now simply becomes transform(). ==================== New methods ==================== For operations requiring caching of the coordinate rotations, the 'R()' method can be used with multiple input points: tensorField rots(cs.R(somePoints)); and later Foam::transformList(rots, someVectors); The rotation() method can also be used to change the rotation tensor via a new coordinateRotation definition (issue #879). The new methods transformPoint/invTransformPoint provide transformations with an origin offset using Cartesian for both local and global points. These can be used to determine the local position based on the origin/rotation without interpreting it as a rthetaz value, for example. ================ Input format ================  Streamline dictionary input requirements * The default type is cartesian. * The default rotation type is the commonly used axes rotation specification (with e1/e2/3), which is assumed if the 'rotation' subdictionary does not exist. Example, Compact specification: coordinateSystem { origin (0 0 0); e2 (0 1 0); e3 (0.5 0 0.866025); } Full specification (also accepts the longer 'coordinateRotation' subdictionary name): coordinateSystem { type cartesian; origin (0 0 0); rotation { type axes; e2 (0 1 0); e3 (0.5 0 0.866025); } } This simplifies the input for many cases.  Additional rotation specification 'none' (an identity rotation): coordinateSystem { origin (0 0 0); rotation { type none; } }  Additional rotation specification 'axisAngle', which is similar to the rotateangle option for transforming points (issue #660). For some cases this can be more intuitive. For example, rotation { type axisAngle; axis (0 1 0); angle 30; } vs. rotation { type axes; e2 (0 1 0); e3 (0.5 0 0.866025); }  shorter names (or older longer names) for the coordinate rotation specification. euler EulerRotation starcd STARCDRotation axes axesRotation ================ Coding Style ================  use Foam::coordSystem namespace for categories of coordinate systems (cartesian, cylindrical, indirect). This reduces potential name clashes and makes a clearer declaration. Eg, coordSystem::cartesian csys_; The older names (eg, cartesianCS, etc) remain available via typedefs.  added coordinateRotations namespace for better organization and reduce potential name clashes.

 28 Jun, 2018 1 commit


Andrew Heather authored

 22 Dec, 2015 1 commit


Andrew Heather authored

 09 Dec, 2015 1 commit


Andrew Heather authored

 10 Dec, 2014 1 commit


Henry authored
