Btukfyl

I'm pretty new to LaTeX, so sorry for the beginner question. I'm trying to align on equals signs within tabular, however a few rows are blank and don't have equals signs. How can I do this? Thanks!

documentclass{article}

usepackage[utf8]{inputenc}

usepackage{multirow, adjustbox, mathtools}

begin{document}



begin{table}[htbp]

begin{adjustbox}{width=columnwidth,center}

  begin{tabular}{|c|c|c|c|c|}

    hline

    Force Field & Calculated Energy & Calculated Difference & Experimental Difference & Error \

    hline



    multirow{4}{*}{OPLS-AA}

        & tt = 2.55447 & && \ cline{2-5}

        & $text{g}^+text{g}^+$ = 4.19785 & $text{g}^+text{g}^+$-tt = 1.64338 & $text{g}^+text{g}^+$-tt = 1.62 & 0.02338 \ cline{2-5}

        & $text{g}^+text{g}^-$ = 5.56306 & $text{g}^+text{g}^-$-tt = 3.00859 & $text{g}^+text{g}^-$-tt = 3.51 & -0.50141 \ cline{2-5}

        & tg = 3.36156 & tg-tt = 0.80709 & tg-tt = 0.86 & -0.05291 \ cline{2-5}

    hline



    multirow{4}{*}{AM1}

        & tt = -37.97281 & && \ cline{2-5}

        & $text{g}^+text{g}^+$ = -36.52659 & $text{g}^+text{g}^+$-tt = 1.44622 & $text{g}^+text{g}^+$-tt = 1.62 & -0.17378 \ cline{2-5}

        & $text{g}^+text{g}^-$ = -35.85939 & $text{g}^+text{g}^-$-tt = 2.11342 & $text{g}^+text{g}^-$-tt = 3.51 & -1.39658 \ cline{2-5}

        & tg = -37.25846 & tg-tt = 0.71435 & tg-tt = 0.86 & -0.14565 \ cline{2-5}

    hline



    multirow{4}{*}{PDDG/PM3}

        & tt = -34.61227 & && \ cline{2-5}

        & $text{g}^+text{g}^+$ = -33.94462 & $text{g}^+text{g}^+$-tt = 0.66765 & $text{g}^+text{g}^+$-tt = 1.62 & -0.95235 \ cline{2-5}

        & $text{g}^+text{g}^-$ = -33.29225 & $text{g}^+text{g}^-$-tt = 1.32002 & $text{g}^+text{g}^-$-tt = 3.51 & -2.18998 \ cline{2-5}

        & tg = -34.38819 & tg-tt = 0.22408 & tg-tt = 0.86 & -0.63592 \ cline{2-5}

    hline

  end{tabular}

end{adjustbox}

end{table}



end{document}

Edit: I don't think this post is duplicate, because my question concerns both aligning multicolumn over equals signs while still leaving certain lines without equal signs, which is not the case in the suggested duplicate.

Here is one approach. I split the columns using = into two columns. To get the spacing right (and save typing) I used @{$null=null$} between the columns. Unfortunately, this meant having to use multicolumn every time I didn't want a = to appear.

The only remaining problem was that when the label is too large, the extra space is added to the right half. To fix that, I calculated the difference and added extra space to the left half using makebox. Now the equal signs are centered.

documentclass{article}

usepackage[utf8]{inputenc}

usepackage{multirow, adjustbox, mathtools}

begin{document}



begin{table}[htbp]

begin{adjustbox}{width=columnwidth,center}

  sbox0{Calculated Difference}%

  sbox1{Experimental Difference}%

  sbox2{$null=null$}%

  dimen0=dimexpr 0.5wd0 - 0.5wd2relax

  dimen1=dimexpr 0.5wd1 - 0.5wd2relax

  begin{tabular}{|c|r@{$null=null$}l|r@{$null=null$}l|r@{$null=null$}l|c|}

    hline

    Force Field & multicolumn{2}{c|}{Calculated Energy} & multicolumn{2}{c|}{Calculated Difference} & multicolumn{2}{c|}{Experimental Difference} & Error \

    hline

    multirow{4}{*}{OPLS-AA}

        & tt & 2.55447 & multicolumn{2}{c|}{} & multicolumn{2}{c|}{} & \ cline{2-8}

        & $text{g}^+text{g}^+$ & 4.19785 & makebox[dimen0][r]{$text{g}^+text{g}^+$-tt} & 1.64338

          & makebox[dimen1][r]{$text{g}^+text{g}^+$-tt} & 1.62 & 0.02338 \ cline{2-8}% note makebox

        & $text{g}^+text{g}^-$ & 5.56306 & $text{g}^+text{g}^-$-tt & 3.00859 & $text{g}^+text{g}^-$-tt & 3.51 & -0.50141 \ cline{2-8}

        & tg & 3.36156 & tg-tt & 0.80709 & tg-tt & 0.86 & -0.05291 \ cline{2-8}

    hline



    multirow{4}{*}{AM1}

        & tt & -37.97281 & multicolumn{2}{c|}{} & multicolumn{2}{c|}{} & \ cline{2-8}

        & $text{g}^+text{g}^+$ & -36.52659 & $text{g}^+text{g}^+$-tt & 1.44622 & $text{g}^+text{g}^+$-tt & 1.62 & -0.17378 \ cline{2-8}

        & $text{g}^+text{g}^-$ & -35.85939 & $text{g}^+text{g}^-$-tt & 2.11342 & $text{g}^+text{g}^-$-tt & 3.51 & -1.39658 \ cline{2-8}

        & tg & -37.25846 & tg-tt & 0.71435 & tg-tt & 0.86 & -0.14565 \ cline{2-8}

    hline

    multirow{4}{*}{PDDG/PM3}

        & tt & -34.61227 & multicolumn{2}{c|}{} & multicolumn{2}{c|}{} & \ cline{2-8}

        & $text{g}^+text{g}^+$ & -33.94462 & $text{g}^+text{g}^+$-tt & 0.66765 & $text{g}^+text{g}^+$-tt & 1.62 & -0.95235 \ cline{2-8}

        & $text{g}^+text{g}^-$ & -33.29225 & $text{g}^+text{g}^-$-tt & 1.32002 & $text{g}^+text{g}^-$-tt & 3.51 & -2.18998 \ cline{2-8}

        & tg & -34.38819 & tg-tt & 0.22408 & tg-tt & 0.86 & -0.63592 \ cline{2-8}

    hline

  end{tabular}

end{adjustbox}

end{table}



end{document}