Height of equation number in multiline equation

I have found some satisfying start of answer to my problem on this related post` Sadly with the code displayed hereunder, the equation number is displayed on the same level as the last equation line (on picture here even lower because the line is so long). Can anyone tell me how to set the height of the equation number to be the same as the second line? \documentclass[11pt, a4paper, twocolumn]{article}

%\input{structure.tex}
\usepackage{bm}
\usepackage{graphicx}

\usepackage{etoolbox}
\usepackage{float}
\usepackage[english]{babel} % English language hyphenation
\usepackage{amsmath,amsfonts,amsthm}

\begin{document}

\begin{equation}\label{eq:DCKE}
\begin{aligned}
\frac{\delta}{\delta t}&p(\textbf{z},t) = -\sum_i{\frac{\delta}{\delta z_i} [A_i(\textbf{z},t)p(\textbf{z},t)]}\\
& +\sum_{ij}{\frac{1}{2}\frac{\delta ^2}{\delta z_i\delta z_j}[B_{ij}(\textbf{z},t)p(\textbf{z},t)]}\\
& +\int{}d\textbf{y}[W(\textbf{z}\mid\textbf{y},t)p(\textbf{z},t)-W(\textbf{y}\mid     \textbf{z},t)p(\textbf{z},t)]
\end{aligned}
\end{equation}
\end{document}]
• @DavidCarlisle I just edited to make it work. Sep 10 '18 at 17:33
• It seems that the lower positioning is related to the width of your equations. If you remove the twocolumn option from your class, it works as supposedly expected Sep 10 '18 at 17:34
• This is precisely what the \raisetag command is for. See tex.stackexchange.com/questions/299407/…. Sep 10 '18 at 18:55

When typesetting in two column format, long math formulas are always a PITA.

An aligned construction always makes a single object and the equation number will be lowered in case it doesn't fit.

On the other hand, align checks for the space on every line.

\documentclass[11pt, a4paper, twocolumn]{article}
\usepackage{amsmath}

\begin{document}

\begin{align}
&\frac{\delta}{\delta t}p(\mathbf{z},t) =
-\sum_i{\frac{\delta}{\delta z_i} [A_i(\mathbf{z},t)p(\mathbf{z},t)]}
\notag\\
& +\sum_{ij}{\frac{1}{2}\frac{\delta ^2}{\delta z_i\delta z_j}
[B_{ij}(\mathbf{z},t)p(\mathbf{z},t)]}
\label{eq:DCKE}\\
& +\int{}d\mathbf{y}[W(\mathbf{z}\mid\mathbf{y},t)p(\mathbf{z},t)-
W(\mathbf{y}\mid     \mathbf{z},t)p(\mathbf{z},t)]
\notag
\end{align}

\end{document}

I changed the alignment point in order to make the last line to fit.

I also changed all \textbf commands into the correct \mathbf. • I would upvote that answer if I had enough reputation.. Thank you very much! Works like a charm Sep 11 '18 at 9:21
• @Mazata Unfortunately, this requires a bit of handiwork, but, as I said, typesetting math in two column format is hard. Sep 11 '18 at 10:05