# [texhax] Strange alignment in memoir+gather

Thu Mar 25 14:32:39 CET 2010

Barbara Beeton wrote:
> On Thu, 25 Mar 2010, Lars Madsen wrote:
>
>     Barbara Beeton wrote:
>     > On Thu, 25 Mar 2010, Lars Madsen wrote:
>     >
>     >     Victor Ivrii wrote:
>     >     > On Wed, Mar 24, 2010 at 10:28 AM, Victor Ivrii <vivrii at gmail.com>
>     > wrote:
>     >     > > This seems to be almost minimal example as effect is extremely
>     >     > > unstable and disappears as some parts of formula are removed. I
>     > have
>     >     > > observed this effect before in some occasions but cannot figure
>     > out
>     >     > > any patterns
>     >     >     > The same effect with amsmath,
>     >
>     >     of course, mathtools loads amsmath, and gahter is not touched by
>     > mathtools
>     >
>     >     it seems to be memoir interacting with something in amsmath
>     >
>     >     Do not know what, yet.
>     >
>     > i've confirmed that the first example
>     > has the same effect with amsart, so it's
>     > undoubtedly a problem in amsmath itself.
>     > it's been put on our bugs list, but will
>     > likely not be debugged (by us) real soon.
>     > if anyone comes up with solid hints,
>     > please send them to the attention of
>     >   tech-support at ams.org
>     > thanks.
>     > 						-- bb
>
>     I don't think it is amsmath, as the effect (the odd centering) goes away if
>     you replace memoir with book
>
> but if you replace memoir with either article
> or book and change the options to [11pt,leqno]
> both examples go haywire.  so your test isn't
> sufficient.
>
> victor said the problem was both fragile and
> intermittent.  since i've managed to replicate
> the problem with three quite unrelated
> document classes, i'm convinced that amsmath
> is the place to start digging.
>
> obviously it's a bad interaction with the
> document class, whatever that may be, and
> apparently is more likely with left-hand
> equation numbers.  i haven't yet found a case
> that fails when \tag isn't used, but i suspect
> that with a long enough "natural" equation
> number (subsubsection + high counter value)
> that would change.  my hunch is that it is
> a bad interaction between the length of the
> eqno and the measuring routine.  there have
> been other bugs related to the measuring
> routine, most allegedly solved, and all
> nearly unpredictably infrequent.
> 						-- bb

you're right, I just made sure that I tested with the same widths, and
the problem went away.

I think Morten H\o gholm may have mentioned this problem at one time.

--

/daleif