DataTypes

As you may know, many SOFA C++ classes are templated, mostly on the type of DOF you want to simulate. Examples of templates can be found in the MechanicalObject page, in the templates section. In the code, the use of templates can be confusing, especially when the type used in place of the template has itself many types. This page provides a short introduction to all these DOF types.

All DOF Types must implement (or define) all the following types:

• Real: corresponds to a double or float value, depending on the DataTypes used: a class templated in Vec3d will return a double, whereas a a class templated in Vec3f will return a float

• Coord: standing for “coordinate”, corresponds to a vector of Real with a size given by the number of degrees of freedom: a class templated in Vec6d will return a vector of 6 doubles. This vector is homogeneous to your degrees of freedom.

• Deriv standing for “derivative”, corresponds to a vector of Real with a size given by the number of degrees of freedom: a class templated in Vec6d will return a vector of 6 doubles

• VecCoord or VecDeriv: correspond to a vector of respectively Coord or Deriv

• DataVecCoord or DataVecDeriv: correspond to a Data containing a vector of respectively Coord or Deriv. As noted in the associated article, the Data are variable of the class exposed to the user and other components in the scene

• MatrixCoord or MatrixDeriv: correspond to a matrix of respectively Coord or Deriv, this is more especially used by solvers and constraint algorithms

• VecCoordId, VecDerivId, MatrixCoordId or MatrixDerivId: correspond to an identifiant value (int) pointing to a vector or matrix of respectively Coord or Deriv. This is very useful to access specific vectors or matrix in the simulation. State vectors for instance are managed with specific protected Ids by the solvers.