Proposal to split out the "members" from coreQ (Was: Re: Philosophy of basic Q)
brian.thomas at gsfc.nasa.gov
Tue May 11 14:06:55 PDT 2004
On Tuesday 11 May 2004 03:11 pm, David Berry wrote:
> On Tue, 11 May 2004, Brian Thomas wrote:
> > > Also, no one seems to have noticed that CoreQ allows for either arrays
> > > or components (parent-child structure) BUT NOT BOTH at the same time!!!
> > I have noticed. In our original proposal this was called a "quantityset".
> > In the implementation I am working on, I have a QuantitySet class which
> > only takes members, and a "ListQuantity" class that only takes values.
> What is a QuantitySet?
A quantity which is a composite of other quantities. Effectively, the
"CoordsQuantity" *is* such a thing as it holds axes (which are Quanitities).
Currently "CoordsQuantity" meets the interface of "CoreQuantity".
> What are "members"?
The quantities which are inside another quantity and represent "data".
> > Look, we agree on the following :
> > We *do* need a quantity which is a composite of other quantities.
> Why? What do you mean by "composite"? Do you mean that the values stored
> in the Quantity are themselves Quantities, or that a Quantity holding a
> list of 2-D values can be split into a pair of 1-D quantities?
Yes, the values stored inside the quantity are themselves quantities.
> > All that is needed then is to create a QuantitySet/CompositeQuantity
> > interface by peeling off the needed methods from coreQ.
> Why? What does this give us?
As I said above it is needed for use as "CoordsQuantity", although it
has use as a means to replicate tables and other things which are
quantities composed of other quantities.
> > I don't believe it is too late to revise this to separate out the
> > "member" stuff from Core/Standard Q and put it in a separate interface.
> > What do other people think?
> I think that this is all new stuff which I for one have not seen clearly
> defined or justified anywhere. I think you need to start from the
> beginning and say clearly what a QuantitySet is and why it is needed.
You have seen it, it exists in the current serialization. The language is
just perhaps different from what you have heard before.
> Dr David S. Berry (dsb at ast.man.ac.uk)
> STARLINK project | Centre for Astrophysics
> (http://www.starlink.ac.uk/) | University of Central Lancashire
> Rutherford Appleton Laboratory | PRESTON
> DIDCOT | United Kingdom
> United Kingdom | PR1 2HE
> OX11 0QX Tel. 01772 893733
> 01257 273192
* Dr. Brian Thomas
* Dept of Astronomy/University of Maryland-College Park
* Code 630.1/Goddard Space Flight Center-NASA
* fax: (301) 286-1775
* phone: (301) 286-6128 [GSFC]
(301) 405-2312 [UMD]
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