Jack Lovell

Yes, this think this is fine to do. The original SART implementation (which inspired Vlad's OpenCL variant, I believe) had a non-negativity constraint because the expected use case was inverting...

Add the tests to here: https://github.com/cherab/core/blob/master/cherab/tools/tests/test_sart_opencl.py. You can re-use the geometry matrix Vlad made for the existing tests, but you'll want a new solution vector that has negative numbers in...

You could use the [VectorCamera](https://www.raysect.org/api_reference/optical/observers.html#raysect.optical.observer.imaging.vector.VectorCamera), and give it an of shape `[1, nlos]` of pixel locations and LOS vectors, one for each pixel in your proposed setup. Note that VectorCamera...

Hmm, I don't think you can directly specify a FOV with the VectorCamera. Maybe then a [FibreOptic](https://www.raysect.org/api_reference/optical/observers.html#raysect.optical.observer.nonimaging.fibreoptic.FibreOptic) would be better, where you specify the acceptance angle. Or a `TagetedPixel` (sadly...