# Onecolumn till end of page in twocolumn mode

I know about using the `widetext` environment for setting text in onecolumn mode and the `multicols` package for effortless switching between one- and twocolumn mode, but I think this is not too great if the onceolumn text is very close to the bottom of the page. I'd like to put some text in onecolumn mode and have latex format the remainder of the page in onecolumn mode if the initial text is close to the bottom of the page. Have a look at this:

Note that the text after the CKM matrix (which is set in onecolumn-mode) is set in onecolumn mode, which I think is very pleasing to the eye.
Is there any solution to my question?

PS: Another solution I've been thinking about would be a float-like math environment which could be set with the `b` option but I'd fear the possibility that it floats to the next page.

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Does the material on the next page of the paper revert to twocolumn mode? –  Mico Jun 13 '12 at 21:14
There's another one-column matrix and then it is reverted to twocolumn mode. –  elemakil Jun 13 '12 at 21:17
to be honest, I don't think that mixing one- and two-column layout in a text flow generates a nice result (I really don't like the example you posted). I don't speak about wide floats in two-column mode, they're fine, but this looks somehow confusing. (Of course, this comment has nothing to do with the problem questioned.) –  tohecz Jun 13 '12 at 21:59
I respect this and I'm not fully satisfied with the results depicted above either but I think splitting splitting a small number of lines below a onecolumn equation looks rather irritating and a careless reader might miss them. Up to now I have always used a float container positioned at bottom (see my PS text above) but it is quite annoying to check whether it has floated off page. –  elemakil Jun 13 '12 at 23:08

The reason that `multicols`can switch between different column numbers is due to the fact that there the user specifies where in the source this happens not where in the output.
Having said that: yes TeX is Turing machine and yes, if you disable a lot of that in-built functionality of TeX and manage everything by ourself, then there are ways to achieve something like this. Basically one has to measure how much space is left to the bottom of the next page, then how long the next paragraph will be and if it wouldn't fit, build a `\parshape` definition that changes the column width at the right point. Unfortunately there are all kind of complications that go with this approach (and it is difficult to make if work in a general way, that is if the text could contain any kind of TeX construct and formulas etc).