NiftyRegf3d parameters docs.

[AnderBiguri]

As far as I understand there is no way for a user to link NiftyReg's reg_f3d -h docs (really, the only user-oriented docs they seem to have) to sirf.Reg.NiftyRegf3d's set_params function.

One can see the wrapped functions using print_all_wrapped_methods however these do not have the same names as reg_f3d -h variables and the best one can do is assume what they do.

e.g. from the reg_f3d help:

[reg_f3d] *** Spline options (All defined at full resolution):
[reg_f3d]       -sx <float>             Final grid spacing along the x axis in mm (in voxel if negative value) [5 voxels]
[reg_f3d]       -sy <float>             Final grid spacing along the y axis in mm (in voxel if negative value) [sx value]
[reg_f3d]       -sz <float>             Final grid spacing along the z axis in mm (in voxel if negative value) [sx value]

is this the same as SetSpacing(unsigned,dataType) ? possibly, maybe. Or is it not wrapped?

EDIT: apparently the usage is set_parameter("SetSpacing", "2", "-10"), which is not clear by the prior function signature given.

In general, its not documented.

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This has the unfortunate effect of basically either making the user to read the source code of possibly 2 repositories, or simply being completely hidden and "not existent". Ideally we would want to let users know what they can do and how. So how can we document this?

Chatting with @rijobro it seems that the solution is not necessarily trivial. The SetXX functions are wrapped and can be valid for more than just f3d.

He suggested adding some docs in /src/Registration/callable_NR_f3d_methods.txt .

I am not sure where they would be best, but as always, I think that the python user should have direct/easy access to the docs/input args of the functions they are using, and not need to "search" many layers.

Any thoughts on how to tackle this are welcome