[Users] Possible performance issue with some codes

[Erik Schnetter]

On Wed, Aug 17, 2011 at 11:30 PM, Roland Haas
<roland.haas at physics.gatech.edu> wrote:

> Precisely because ADMBase is used by everyone, it would have been nice
> if its public interface had not changed :-). Even if the old interface
> is now considered faulty in some situations.

It didn't change... You were performing unnecessary work all along
because both ADMBase and your code evolved the ADMBase variables.
Since ADMBase came first, your code overwrote this, so no one was
hurt; and since ADMBase didn't perform any expensive operations, you
didn't notice.

We are discussing here whether to keep a known bug in ADMBase's
default parameter settings to help people save time improving
performance of private codes that don't follow the ADMBase standard.
ADMBase is a really basic, really important thorn for many people, and
it needs to be correct and not surprise first-time users. Changing its
interface requires much thinking, including about users who are not
vocal on these mailing lists.

There's nothing wrong with discussing some of the ADMBase and friends'
design decisions; in particular, CoordGauge and StaticConformal come
to my mind. But given the user base, this requires careful planning,
prominent announcements to the community, and we will have to help
people update their codes. We will probably end up supporting both
versions for some time. Given that the next ET release focuses on
infrastructure improvements, we may want to leave this for another
round -- that would then be a "cleanup" release where we focus on
clarity, tutorials, debuggability, and improving performance by making
sure all the "little things" are in order.

-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>   http://www.cct.lsu.edu/~eschnett/