Constructor documentation duplication about pygsti

[sserita]

Yea this (and related topics) is something we've discussed several times. The Google style guide suggests that the parameters should only be described in __init__, whereas the class docstring should just give an overview of the class (and also any public attributes, which we rarely document).

I am generally for removing duplicated documentation - it greatly increases our ability to maintain the code. Basically any time we find ourselves copy-pasting docstrings, I would rather do something else. One thing I've been playing around with in other projects is using See Also blocks or just saying that other parameters are documented in :meth:some_other_func. This has the disadvantage of having to manually searching for that function while developing (although IDEs may lower this barrier some), but has the advantage that Sphinx will create hyperlinks to that function in the autogenerated documentation. This is particularly helpful for parameters that are just being plumbed through to other functions. As my current goal basically is to make the ReadTheDocs the one-stop shop for all pyGSTi documentation (both tutorials and API reference), the pros of doing this referencing/linking greatly outweigh the cons for me, but I'm open to being convinced otherwise.

[sserita]

I also remember @rileyjmurray talking about docstring templates at some point, but can't remember the exact context.

[rileyjmurray]

I'm also fine with removing duplicated documentation. In this case I think that straight-up deleting the class docstrings and keeping in __init__ is reasonable.

Responding to Stefan's last comment, here's a super simple decorator definition that can programmatically populate docstrings:

def set_docstring(docstr):
    def assign(fn):
        fn.__doc__ = docstr
        return fn
    return assign

Here's how I used it in other projects. The idea was to define an interface class that included a template docstring with a few blank spots, then subclasses would define a tuple of strings called that held content to substitute into the template.

class TaskInterface:
    """
    Class for doing the useful thing.
    """
    
    TEMPLATE_DOCSTR = """
    Given x and y, approximately compute 
    
        the_thing(x, y).
        
     %s
     Parameters
     ------------
     x : something
     y : something
     tol : float
         %s
    
    Returns
    --------
     val : something
     
     %s
    """
    
    # Dummy values
    INTERFACE_FIELDS = (
    """
    Use [the method].
    """,
    """
    We use an iterative method, and stop once [metric] falls below tol.
    """,
    """
    Note, "val" is guaranteed to satisfy [condition].
    """
    )
    
    DOCSTR = TEMPLATE_DOCSTR % INTERFACE_FIELDS
    
    @set_docstring(DOCSTR)
    def __call__(x, y, tol):
        raise NotImplementedError()