Cfrgtkky

In the align environment, it automatically labels consecutive lines within the same environment as (1),(2),...,(n), line by line. But I want it to organize equations more properly and use (1.0), (1.1), (1.2)... for the first equation in the first align environment, and then (2.0), (2.1), (2.2)... and etc for consecutive equations in following separate align environments. Is there a way to do this?

I suggest you load the etoolbox package and use the patchcmd macro to "patch" the subequations environment in two places.

documentclass{article}

usepackage{amsmath}  % for 'align' and 'subequations' environments

usepackage{etoolbox} % for 'patchcmd' macro

patchcmd{subequations}{{0}}{{-1}}{}{}       % decrement the equation counter

patchcmd{subequations}{alph}{.arabic}{}{} % change display format of eq. counter



begin{document}



begin{subequations}

begin{align}

1+1=2\

2+2=4\

3+3=6

end{align}

end{subequations}



begin{subequations}

begin{align}

4+4=8\

0+0=0\

1-1=0

end{align}

end{subequations}

end{document}

Use mathtools package to edit equation brackets. Use patchcmd from etoolbox to customize the way subequations tags will look like.

Equations and subequations start at 1 when numbered. To change this behavior, use AtBeginEnvironment from etoolbox

documentclass{book}



    usepackage{amsmath}

    renewcommand{theequation}{arabic{equation}}



    usepackage{amssymb, amsfonts}

    usepackage{adjustbox}

    usepackage{mathtools}



        newtagform{eqbrackets}{(}{)}

        usetagform{eqbrackets}





    usepackage{etoolbox}

    patchcmd{subequations}{alph{equation}}{.arabic{equation}}{}{}

    AtBeginEnvironment{alignat}{addtocounter{equation}{-1}}





begin{document}







begin{subequations}





    begin{alignat}{3}

        I_{sc} & = I_{sc,ref} & bigg[  1 + frac{alpha}{100} (T_{op}-T_{ref}) biggl]

        label{eq:SubEq1}

        \

        %

        V_{oc} & = V_{oc,ref} & bigg[  1 + frac{beta}{100} (T_{op}-T_{ref}) biggl]

        label{eq:SubEq2}

        \

        %

        P_{mp} & = P_{mp,ref} & bigg[  1 + frac{gamma}{100} (T_{op}-T_{ref}) biggl]

        label{eq:SubEq3}

    end{alignat}



end{subequations}



See SubEq. ref{eq:SubEq1}



begin{subequations}



    begin{alignat}{3}

        I_{sc} & = I_{sc,ref} & bigg[  1 + frac{alpha}{100} (T_{op}-T_{ref}) biggl]

        label{eq:SubEq4}

        \

        %

        V_{oc} & = V_{oc,ref} & bigg[  1 + frac{beta}{100} (T_{op}-T_{ref}) biggl]

        label{eq:SubEq5}

        \

        %

        P_{mp} & = P_{mp,ref} & bigg[  1 + frac{gamma}{100} (T_{op}-T_{ref}) biggl]

        label{eq:SubEq6}

    end{alignat}



end{subequations}



See SubEq. ref{eq:SubEq5}



begin{subequations}



    begin{alignat}{3}

        I_{sc} & = I_{sc,ref} & bigg[  1 + frac{alpha}{100} (T_{op}-T_{ref}) biggl]

        \

        %

        V_{oc} & = V_{oc,ref} & bigg[  1 + frac{beta}{100} (T_{op}-T_{ref}) biggl]

        \

        %

        P_{mp} & = P_{mp,ref} & bigg[  1 + frac{gamma}{100} (T_{op}-T_{ref}) biggl]

    end{alignat}



end{subequations}







end{document}