If control points and momenta corresponding to a deformation have been obtained in txt format, it is possible to shoot the corresponding deformation of obtain the flow of a shape under this deformation.
A toy example
An example of this procedure is available in the folder examples/shooting/landmark/3d/brain_structures.
The model.xml file must specify the shooting model, and contain a template which will undergo the deformations listed in the initial-control-points and initial-momenta file. Note that the provided files must be in txt format similar to the output of a deformetrica run. The initial-momenta file can contain a single momenta or a list of momenta (e.g. the output of an atlas estimation), in which case the template will be deformed along to each of the deformations listed, and all the flows will be saved.
By default, the flow will be computed between t=0 and t=1. To obtain a different time domain, specify the tmin and tmax parameters in the deformation-parameters section of the model.xml file. Note that we must have tmin <= 0 <= tmax, and the control points and momenta are assumed to be given at t=0.
Shooting is a forward computation, and does not require a data_set.xml file. The generic command line is in this case deformetrica compute model.xml -p optimization_parameters.xml. In our example, we even drop the optional optimization_parameters.xml, and therefore simply launch the shooting application with deformetrica compute model.xml.