Re: FieldImpl Extended: extractValues

Hi Randall,

> Here are a couple additional methods for the FieldImpl class.  They
> accomplish the same result as a call to "extract" followed by a call to
> "getValues".  However, by eliminating the creation of a new Field (like
> "extract" does), they run significantly faster.  I implemented them as a new
> class that extends FieldImpl, but if you like them, you could add them into
> FieldImpl itself.  These are based on the VisAD version with a doc/DATE of
> Thu Nov 1 09:21:01 CST 2001.  (Is that the right way to identify a VisAD
> version?)

This is what we call a utility method: it encapsulates some
logic using VisAD's existing methods. Because VisAD is so
large and complex, we are resisting the addition of utility
methods to the system. There are an increasing number of
other software packages that use VisAD and add all sorts
of utility methods and other extensions, and we are happy
to create links to these from the VisAD web page. We will
be happy to link if you want to make a VisAD-based package
available.

By the way, in addition to resisting the addition of utility
methods, I am strongly resisting system changes that will
break existing applications. This is not always easy, since
there are certainly ways that the system could be better.

We are trying to focus new development in packages that add
new functionality or performance to the system. Examples
include the cluster visualization work, support for Python,
the visad.bio package for biological data and tasks, and
interfaces of the VisAD data model to new file and server
formats. The graph layout algorithms discussed recently on
this list are another good example.

Cheers,
Bill
----------------------------------------------------------
Bill Hibbard, SSEC, 1225 W. Dayton St., Madison, WI  53706
hibbard@xxxxxxxxxxxxxxxxx  608-263-4427  fax: 608-263-6738
http://www.ssec.wisc.edu/~billh/vis.html