# Is it good style to make a multline formula float? [closed]

I am using the `multline` environment to typeset rather large formulas that take up 1/3 of the page. Since the `multline` environment does not break across pages, layouting of the text before the environment is at times rather ugly (since the formula will only start at the top of the next page).

I was thinking about making the `multline` environment float, e.g. by wrapping it within a `figure` environment. Is this acceptable style? Should it be avoided?

• Not exactly a TeX question, so I'm posting this as comment rather than answer: I would strongly discourage making an equation float, since a formula is somehow part of the sentence. It would make at least my papers unreadable. The best way to cope with a very long formula is IMO to introduce abbreviations. Or to use `\displaybreak` (though that is usually my very last resort). Again, IMHO. – campa May 5 '17 at 14:06
• I concur with @campa; in many writings (both my own and by other authors), equations are part of a sentence, so floating them doesn't seem very sane to me. But you could of course, in theory, restructure your text to adapt accordingly. Still, I wouldn't advise this personally. Have you considered using `align` instead of `multline`, if the formulae really, absolutely, positively cannot be shortened? Those can break across pages. See this answer: tex.stackexchange.com/a/24905/131649 – alpenwasser May 5 '17 at 14:14
• "... Since the `multline` environment does not break across pages ..." -- this is only true if you don't issue the directive `\allowdisplaybreaks`. – Mico May 5 '17 at 14:22
• Abbreviate parts of the equation, or define new variables elsewhere in the document for substitution in the large equation (basically the same thing). – Mike Renfro May 5 '17 at 15:46

As mentioned in comments `amsmath` environments will break if you use `\allowdisplaybreaks`.
If you do not want them to break and you have a lot of large expressions it is possible (but not common) to float them however in that case you should define a custom `eqnfloat` type and not use `figure`, and use the floating environment for all numbered equations.
Defining a new float type in addition to `table` and `figure` is not hard, but is perhaps simplest done with the specific declarations that the `float` package provides for that purpose.