Homogenize Regularizer Interface

[JakobAsslaender]

Just to keep track of things: There are a few inconsistencies between regularizers that we should maybe fix. To get a list started:

• LLRRegularization takes the image size as the parameter shape, i.e. without extra (time) dimension. In contrast, TVRegularization takes the full matrix size.
• LLRRegularization is applied along the last dimension, while TVRegularization takes dims as a parameter.

[nHackel]

One idea we had in regards to the shape/size keyword is to move it out of the regularization terms and into the solvers.

Then the prox! call can be invoked with a reshaped array. For the reg. terms that just perform element-wise this has no effect and the other terms we have atm would apply the reshape anyways.

A default value for the shape could then be size(A,2) or size(AHA, 1) respectively and if multidimensional solutions are wanted then a user can supply the (for example image) size

[JakobAsslaender]

Interesting idea. But I do think there is some logic to keeping the shape in the regularizers. E.g., if you have 5D data, say, 3 spatial and 2 other dimensions, it might make sense to have the flexibility to have a 2D TV along those extra dimensions, or, instead, do an LLR along the last to concatenate. I had in mind to change the LLR code to take the full reshape size and a dims::Number keyword.

[tknopp]

yes, if only a subset of dimensions is to be considered, we should use the dims keyword, which can not only be a number but also a range or a vector.