Parameters of `ConeBeamModel.__init__`

[bwohlberg]

ConeBeamModel.__init__ only provides for direct setting of four parameters):

mbirjax/mbirjax/cone_beam.py

Line 51 in 25950c1

def __init__(self, sinogram_shape, angles, source_detector_dist, source_iso_dist):

As a result, if additional parameters need to be set (e.g. recon_slice_offset, or delta_voxel), it has to be achieved via calls to set_params. Is it not possible to include **kwargs, which would be passed to **kwargs of the parent class initializer?

Also, with respect to documentation of these additional parameters:

• It would be helpful to document how the default value of delta_voxel is set (apparently in a way that maintains the same effective magnification at the detector, independent of the value returned by get_magnification).
• The note One additional parameter for ConeBeamModel that can be set using set_params() is ... could be read to imply that there is only one additional relevant parameter, but this does not seem to be the case.

[cabouman]

Brendt, your comment about **kwargs is above my paid grade. So I'll let Greg answer that one.

However, I did my best to address your points about the default values of delta_voxel. To do this, I updated the docs for the next release of the code.

I also updated the parallel beam geometry docs to explain the default parameter settings for that case.

We wrote the code so that if you run recon, you always get a reasonable reconstruction. However, that also makes some of the parameter settings a bit opaque.

[bwohlberg]

Brendt, your comment about **kwargs is above my paid grade. So I'll let Greg answer that one.

Since TomographyModel.__init__ already takes **kwargs, it should be straightforward. For example, for ParallelBeamModel, I would expect something like this to work:

def __init__(self, sinogram_shape, angles, **kwargs):
    if "view_params_name" in kwargs.keys():
        raise RuntimeError("Parameter view_params_name may not be passed as a keyword argument")
    angles = jnp.asarray(angles)
    view_params_name = 'angles'
    super().__init__(sinogram_shape, angles=angles, view_params_name=view_params_name, **kwargs)

However, I did my best to address your points about the default values of delta_voxel. To do this, I updated the docs for the next release of the code.

I also updated the parallel beam geometry docs to explain the default parameter settings for that case.

Thanks Charlie, that's very helpful.