# Equations inside tabular environment, no vertical spacing

I have a problem with the spacing of my equations. According to this http://tex.stackexchange.com/a/50348/15360 booktabs one should rarely have to regulate the spacing.

But the result of the code below gives me:

\documentclass[a4paper,10pt,twoside]{article}
\usepackage[cmex10]{amsmath}
\usepackage{booktabs}
\usepackage{multirow}
\usepackage{floatrow}
\begin{document}
\begin{table}[htb!]
\renewcommand{\arraystretch}{1.2}
\caption{Parameters which Torque logs.}
\label{tbl:2_1_1}
\begin{tabular}{c|c|c}
\toprule
{$\mathbf{q_1/q_2}$} & {$\mathbf{0}$} & {$\mathbf{1}$}       \\ \midrule
\multirow{2}{*}{$\mathbf{0}$}                                &
$\displaystyle\frac{\mathrm{d}v_C}{\mathrm{d}t} = -\frac{1}{C}I_\mathrm{load}$                                  &
$\displaystyle\frac{\mathrm{d}v_C}{\mathrm{d}t} = \frac{1}{C}i_L - \frac{1}{C}I_\mathrm{load}$                  \\
&
$\displaystyle\frac{\mathrm{d}i_L}{\mathrm{d}t} = -\frac{R_L}{L}i_L$                                            &
$\displaystyle\frac{\mathrm{d}i_L}{\mathrm{d}t} = -\frac{1}{L}v_C - \frac{R_L}{L}i_L$                       \\ \hline
\multirow{2}{*}{$\mathbf{1}$}                            &
$\displaystyle\frac{\mathrm{d}v_C}{\mathrm{d}t} = -\frac{R_L}{L}i_L - \frac{1}{L}V_s$                       &
$\displaystyle\frac{\mathrm{d}v_C}{\mathrm{d}t} = \frac{1}{C}i_L - \frac{1}{C}I_\mathrm{load}$                  \\
&
$\displaystyle\frac{\mathrm{d}i_L}{\mathrm{d}t} = -\frac{1}{C}I_\mathrm{load}$                                  &
$\displaystyle\frac{\mathrm{d}i_L}{\mathrm{d}t} = -\frac{1}{L}v_L - \frac{R_L}{L}i_L + \frac{1}{L}V_s$          \\ \bottomrule
\end{tabular}
\end{table}
\end{document}


I also used \begin{aligned} ... \end{aligned} for combining the equations such that you don't have to use the \multirow command.

\documentclass[a4paper,10pt,twoside]{article}
\usepackage[cmex10]{amsmath}
\usepackage{booktabs}
\usepackage{multirow}
\usepackage{floatrow}
\begin{document}
\begin{table}[htb!]
\caption{Parameters which Torque logs.}
\label{tbl:2_1_1}
\begin{tabular}{c|c|c}
\toprule
{$\mathbf{q_1/q_2}$} & {$\mathbf{0}$} & {$\mathbf{1}$}            \\ \midrule
{$\mathbf{0}$} &
\begin{aligned} \frac{\mathrm{d}v_C}{\mathrm{d}t} &= -\frac{1}{C}I_\mathrm{load} \\ \frac{\mathrm{d}i_L}{\mathrm{d}t} &= -\frac{R_L}{L}i_L \\ \end{aligned}
&
\begin{aligned} \frac{\mathrm{d}v_C}{\mathrm{d}t} &= \frac{1}{C}i_L - \frac{1}{C}I_\mathrm{load} \\ \frac{\mathrm{d}i_L}{\mathrm{d}t} &= -\frac{1}{L}v_C - \frac{R_L}{L}i_L \\ \end{aligned}                                  \\ \hline
{$\mathbf{1}$} &
\begin{aligned} \frac{\mathrm{d}v_C}{\mathrm{d}t} &= -\frac{R_L}{L}i_L - \frac{1}{L}V_s \\ \frac{\mathrm{d}i_L}{\mathrm{d}t} &= -\frac{1}{C}I_\mathrm{load} \\ \end{aligned}
&
\begin{aligned} \frac{\mathrm{d}v_C}{\mathrm{d}t} &= \frac{1}{C}i_L - \frac{1}{C}I_\mathrm{load} \\ \frac{\mathrm{d}i_L}{\mathrm{d}t} &= -\frac{1}{L}v_L - \frac{R_L}{L}i_L + \frac{1}{L}V_s \\ \end{aligned}                                  \\ \bottomrule
\end{tabular}
\end{table}
\end{document}


Playing with arraystretch or \\[8mm] didn't help either.

-
I suggest dropping the use of vertical rules, as purported in the booktabs documentation. See also How to add extra spaces between rows in tabular environment? Why didn't playing [around] with \arraystretch or \\[<len>] help? –  Werner Mar 2 '13 at 0:49
@Werner \arraystretch did work at some value but the header then got far to big, e.g. to much vertical spacing. But I fixed it now... I don't know why \[<len>] didn't help but \addlinespace did. –  WG- Mar 2 '13 at 1:03
@Werner: I think you mean "proposed" or "propounded", not "purported", which doesn't make sense here. :P –  Noldorin Aug 25 '13 at 17:10

Here's a possibility; I omitted the vertical rules: there's (almost) never need for them.

\documentclass[a4paper,10pt,twoside]{article}
\usepackage{amsmath}
\usepackage{booktabs}
\usepackage{caption}
\captionsetup[table]{position=top}
\begin{document}
\begin{table}[htb!]
\centering
\caption{Parameters which Torque logs.}
\label{tbl:2_1_1}
\begin{array}{cll} \toprule \mathbf{q}_1/\mathbf{q}_2 & \multicolumn{1}{c}{\mathbf{0}} & \multicolumn{1}{c}{\mathbf{1}} \\ \midrule \addlinespace \mathbf{0} & \begin{aligned} \frac{\mathrm{d}v_C}{\mathrm{d}t} &= -\frac{1}{C}I_\mathrm{load} \\[1ex] \frac{\mathrm{d}i_L}{\mathrm{d}t} &= -\frac{R_L}{L}i_L \end{aligned} & \begin{aligned} \frac{\mathrm{d}v_C}{\mathrm{d}t} &= \frac{1}{C}i_L - \frac{1}{C}I_\mathrm{load} \\[1ex] \frac{\mathrm{d}i_L}{\mathrm{d}t} &= -\frac{1}{L}v_C - \frac{R_L}{L}i_L \end{aligned} \\ \addlinespace \midrule \addlinespace \mathbf{1} & \begin{aligned} \frac{\mathrm{d}v_C}{\mathrm{d}t} &= -\frac{R_L}{L}i_L - \frac{1}{L}V_s \\[1ex] \frac{\mathrm{d}i_L}{\mathrm{d}t} &= -\frac{1}{C}I_\mathrm{load} \end{aligned} & \begin{aligned} \frac{\mathrm{d}v_C}{\mathrm{d}t} &= \frac{1}{C}i_L - \frac{1}{C}I_\mathrm{load} \\[1ex] \frac{\mathrm{d}i_L}{\mathrm{d}t} &= -\frac{1}{L}v_L - \frac{R_L}{L}i_L + \frac{1}{L}V_s \end{aligned} \\ \addlinespace \bottomrule \end{array}
\end{table}
\end{document}


Note the \addlinespace for leaving a bit more room and the [1ex] spacing between the rows in aligned (it's common to use a spacing when fractions are involved. Left alignment seems preferable.

-
@WG- I changed a bit my answer; the \mathstrut trick is really not necessary and \addlinespace is preferable. –  egreg Mar 2 '13 at 1:08
Okay! Thanks for your answer. As you can see in the comment to my own question I figured out also that \addlinespace could do the trick to add more space. Using the array environment seems also a bit smoother then the tabular environment. –  WG- Mar 2 '13 at 1:14