Reset the counter back to one in every chapter

Question

I have the following code to get a beautiful concept boxes with optional header for every new concept discussed. The code changes the concept number using the counter but I also need to reset it to 1 again in the next chapter. The code is being taken from this group only, hence not everything i understand in it. Kindly help what needs to be done to reset the counter variable "theorem" to 1 again in the next chapter.

    % Preview preamble

    %% LyX 2.0.4 created this file.  For more info, see http://www.lyx.org/.
    %% Do not edit unless you really know what you are doing.
    \RequirePackage{fix-cm}
    \documentclass[11pt,a4paper,english,oldfontcommands,openany]{memoir}
    \usepackage[T1]{fontenc}
    \usepackage[latin9]{inputenc}
    \setcounter{secnumdepth}{3}
    \setcounter{tocdepth}{3}
    \synctex=-1
    \usepackage{wrapfig}
    \usepackage{amsthm}
    \usepackage{amsmath}
    \usepackage{amssymb}
    \usepackage{fixltx2e}
    \OnehalfSpacing

    \makeatletter

    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% LyX specific LaTeX commands.
    \pdfpageheight\paperheight
    \pdfpagewidth\paperwidth


    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Textclass specific LaTeX commands.
    \@ifundefined{lettrine}{\usepackage{lettrine}}{}
     \theoremstyle{definition}
      \newtheorem{example}{\protect\examplename}
      \theoremstyle{definition}
      \newtheorem{defn}{\protect\definitionname}
    \theoremstyle{plain}
    \newtheorem{thm}{\protect\theoremname}

    \@ifundefined{date}{}{\date{}}
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%% User specified LaTeX commands.

    \usepackage[T1]{fontenc}
    \usepackage{amsthm}
    \usepackage{amsmath}
    \usepackage{amsfonts}
    \usepackage{amssymb}

    \usepackage{xcolor}
    \usepackage[framemethod=tikz]{mdframed}
    \usetikzlibrary{shadows,shadings}

    \usepackage[a4paper]{geometry}
    \geometry{
    left=30mm, %% or inner=20mm
    right=15mm, %% or outer=15mm
    top=30mm, bottom=25mm,
    headheight=\baselineskip,
    headsep=7mm,
    footskip=13mm
    }
    \usepackage{multicol}
    \usepackage{polynom}
    \usepackage{lettrine}
    \usepackage{lipsum}
    \usepackage{calc}
    \usepackage{tikz}
    \usetikzlibrary{shapes,snakes}
    \usepackage{pgf}
    \usepackage{graphicx}
    \usetikzlibrary{arrows,mindmap}
    \usepgflibrary{arrows}
    %\usepackage[framemethod=TikZ]{mdframed}

    \usepackage{cwpuzzle}
    %\renewcommand{\secheadstyle}{\huge\bfseries}
    %\chapterstyle{demo3}
    \chapterstyle{verville}
    %\chapterstyle{southhall}
    %chapterstyle{thatcher}
    %\chapterstyle{wilsondob}
    %\chapterstyle{pedersen}
    %\chapterstyle{bianchi}

    \setsubsubsecindent{1cm}
    \setaftersubsubsecskip{1cm}
    \setsubsubsecheadstyle{\Large\itshape\raggedleft
    \begin{tikzpicture}
    \draw[overlay,remember picture,opacity=0.5] node [right,text width=15cm, rounded corners, fill=gray!30, inner sep=2ex]{};
    \draw[thick,overlay,remember picture, gray!50] (0,-.1)--(12.8,-.1);
    \draw[ultra thick,overlay,remember picture, gray!70] (0,-.2)--(12.8,-.2);
    \draw[thick,overlay,remember picture, gray!40] (0,-.3)--(12.8,-.3);
    \draw[ultra thick,overlay,remember picture,gray!70] (0,-.2) -- (-20,-.2);
    \shade[yshift=6pt,ball color=gray,overlay] (0,-.2) circle (9pt);
    \end{tikzpicture}
    }

    \setsubsecindent{0.4cm}
    \setbeforesubsecskip{0.5cm}
    \setaftersubsecskip{0.5cm}
    \setsubsecheadstyle{\Large\scshape\raggedright
    \begin{tikzpicture}
    %\draw[overlay,remember picture,opacity=0.5] node [right,text width=12cm, rounded corners, fill=gray!50, inner sep=2ex]{};
    \draw[yshift=-2pt,remember picture, line width=2pt, overlay, gray!30, rounded corners] (12,-.4) -- (0,-.4) -- (0,.8)  -- (12,.8) -- cycle;
    \draw[thick,overlay,remember picture, gray!50] (0,-.1)--(12,-.1);
    \draw[ultra thick,overlay,remember picture, gray!70] (0,-.2)--(20,-.2);
    \draw[thick,overlay,remember picture, gray!40] (0,-.3)--(12,-.3);
    \draw[ultra thick,overlay,remember picture,gray!70] (0,-.2) -- (-20,-.2);
    \shade[ball color=gray!90,overlay] (0,-.2) circle (3pt);
    \shade[ball color=gray!90,overlay] (12,-.2) circle (3pt);
    \end{tikzpicture}
    }

    \setsecindent{0.4cm}
    \setbeforesecskip{1.5cm}
    \setaftersecskip{1cm}
    \setsecheadstyle{\LARGE\scshape\raggedright\color{black}
    \begin{tikzpicture}
    \draw[yshift=6pt,overlay,remember picture,opacity=0.5] node [right,text width=15.5cm, rounded corners, fill=gray!30, inner sep=15pt]{};
    \draw[yshift=-2pt,remember picture, line width=4pt, overlay, gray, rounded corners] (16,-.4) -- (-0.5,-.4) -- (-0.5,1)  -- (16,1) -- cycle;
    \shade[overlay,ball color=gray] (16,0.2) circle (8pt);
    \end{tikzpicture}
    }

    \setparaindent{1cm}
    \setafterparaskip{1cm}
    \setparaheadstyle{\Large\itshape\raggedright
    \begin{tikzpicture}
    \draw[overlay,remember picture,opacity=0.5] node [right,text width=0.4\textwidth, rounded corners, fill=gray!30, inner sep=2ex]{};
    \draw[thick,overlay,remember picture, gray!50] (0,-.1)--(7.5,-.1);
    \draw[ultra thick,overlay,remember picture, gray!70] (0,-.2)--(7.5,-.2);
    \draw[thick,overlay,remember picture, gray!40] (0,-.3)--(7.5,-.3);
    %\draw[ultra thick,overlay,remember picture,gray!70] (0,-.2) -- (-20,-.2);
    \shade[yshift=6pt,ball color=gray,overlay] (0,-.2) circle (8pt);
    \shade[ball color=gray,overlay](7.5,0) circle (8pt);
    \end{tikzpicture}
    }



    %%%%%%%% This is to get a Concept

    \usepackage{lipsum}







   %  this is the start of the code which is our interest 

    \newcounter{theorem}
    \renewcommand\thetheorem{Concept ~\arabic{theorem}}
    \makeatletter
    \mdf@dolist{\mdf@do@stringoption}{%
        {theoremtitle=={}}%
    }
    \renewrobustcmd\mdfcreateextratikz{%
          \node[anchor=west,rounded corners,draw,thick,shading=axis,left color=gray!20,xshift=10cm,minimum height=.7cm,minimum width=2cm] at (P-|O) 
                  {~\mdf@frametitlefont{\thetheorem}%
                      \ifdefempty{\mdf@theoremtitle}%
                      {~}%
                      {:~\mdf@theoremtitle~}%
                  };
    }
    \makeatother
    \mdfdefinestyle{theoremstyle}{%
    outerlinewidth=1pt,
    innerlinewidth=3pt,
    roundcorner=5pt,
    linecolor=black,
    shadow=true,
    tikzsetting={shading=axis,top color=gray!10},
    innertopmargin=1.2\baselineskip,
    skipabove={\dimexpr0.5\baselineskip+\topskip\relax},
    needspace=3\baselineskip,
    frametitlefont=\sffamily\bfseries,
    settings={\global\stepcounter{theorem}},
    }
    \newenvironment{concept}[1][]
    {\begin{mdframed}[style=theoremstyle,theoremtitle={#1}]
    \relax}{
    \end{mdframed}
    }

    \makeatother



   %%  this is the end of the code which is of our interest 






    \usepackage{babel}
      \providecommand{\definitionname}{Definition}
      \providecommand{\examplename}{Example}
    \providecommand{\theoremname}{Theorem}

            \begin{document}
    \chapter{chapter one}
    \begin{concept}
    first chapter first concept
    \end{concept}
    \chapter{chapter two}
    \begin{concept}
    second chapter first concept
    \end{concept}
    \end{document}

This is a code created by Lyx

The counter code is commented as code required by us above. And the counter variable to reset is named "theorem"

Answer 1

I don't know how to do this with LyX. However, in order that the theorem number is reset at every chapter, the definition should be

\newtheorem{thm}{\protect\theoremname}[chapter]

This will number theorems as "chapter.theorem", so the first theorem in chapter one will be "1.1" and the third in chapter two will be "2.3". If you want the chapter number only, issue

\renewcommand{\thethm}{\arabic{thm}}

just after the previous declaration.

Answer 2

When you specify a new counter, you can use the optional argument to reset this new counter whenever an old counter is stepped: \newcounter{newcounter}[oldcounter]. This means that every time oldcounter is stepped, newcounter is reset to zero. If you want to add such behaviour to a counter that already exists (e.g. provided by some package) or you want to remove such behaviour (e.g. all sections have increasing numbers even after a new chapter command), you can use the chngcntr package, which provides the commands \counterwithin and \counterwithout.

Code

\documentclass[parskip]{scrreprt}
\usepackage[paperwidth=8cm,margin=1cm,paperheight=14cm]{geometry}

\newcounter{mycounter}[chapter]
\setcounter{mycounter}{0}

\begin{document}

\chapter{ONE}

\stepcounter{mycounter}\themycounter

\stepcounter{mycounter}\themycounter

\section{one}

\stepcounter{mycounter}\themycounter

\chapter{TWO}

\stepcounter{mycounter}\themycounter

\section{one}

\stepcounter{mycounter}\themycounter

\section{two}

\stepcounter{mycounter}\themycounter

\stepcounter{mycounter}\themycounter

\chapter{THREE}

\stepcounter{mycounter}\themycounter

\end{document}

Output

Answer 3

I am not sure from your code which counter needs resetting, but here is a way to automatically reset a counter at the start of a chapter. We copy the existing definition of \chapter to \OldChapter:

\let\OldChapter\chapter

Now, change the chapter macro to first set the value of myCounter to 1 as desired, then resssue the previous defintion of what was chapter (but now available as OldChapter:

\renewcommand{\chapter}{\setcounter{myCounter}{1}\OldChapter}

So in the example below I set the counter to 50 before the chapter, and the output we get is:

Code:

\documentclass{book}

\newcounter{myCounter}

\let\OldChapter\chapter
\renewcommand{\chapter}{\setcounter{myCounter}{1}\OldChapter}

\begin{document}

\chapter{First}
Counter at start of chapter is \arabic{myCounter}

\setcounter{myCounter}{50}
Counter before start of chapter is \arabic{myCounter}

\chapter{Second}
Counter at start of chapter is \arabic{myCounter}

\end{document}