[OS X TeX] Re: "! LaTeX Error: No counter 'a' defined."

[John B. Thoo]

Thank you, Herb S and Don G D, for your replies.

On Dec 19, 2010, at 12:00 PM, <macosx-tex-request at email.esm.psu.edu> <macosx-tex-request at email.esm.psu.edu> wrote:

> ------------------------------
> 
> Message: 4
> Date: Sat, 18 Dec 2010 20:14:59 -0600
> From: Herbert Schulz <herbs at wideopenwest.com>
> 
> Well, it looks like something in that chapter is a culprit do you're making some progress.

Reminiscent of trying to pin down a control panel conflict in ye ole Mac operating systems, I divided the suspect file "ch_numthry.tex" into two parts, A1 and B1, and typeset with only one part.  If only B1 caused errors, e.g., then I divided B1 into two parts, A2 and B2, and typeset with only one part.  Continuing in this way, I narrowed down this piece of code that causes the errors:

%%%%%%%%%%%%%%%%%%%% begin rogue code %%%%%%%%%%%%%%%%%%%%%%%
\begin{figure}
\subfigure[Spiral in Fibonacci rectangles.]{%
  \begin{tikzpicture}
  \pgftransformscale{0.4}
%    \draw[very thin,color=gray] (0,0) grid (15,10);
    \draw[color=lightgray] (10,6) rectangle (11,7);
    \draw[color=lightgray] (9,6) rectangle (10,7);
    \draw[color=lightgray] (9,7) rectangle (11,9);
    \draw[color=lightgray] (11,6) rectangle (14,9);
    \draw[color=lightgray] (9,1) rectangle (14,6);
    \draw[color=lightgray] (1,1) rectangle (9,9);

    \draw (11,7) arc (0:-90:1);
    \draw (10,6) arc (-90:-180:1);
    \draw (9,7) arc (180:90:2);
    \draw (11,9) arc (90:0:3);
    \draw (14,6) arc (0:-90:5);
    \draw (9,1) arc (-90:-180:8);
  \end{tikzpicture}
}
\qquad
\subfigure[Golden spiral.]{%
  %% Modified code copied from
  %% <http://www.texample.net/tikz/examples/fibonacci-spiral/>
  %%
  \begin{tikzpicture}%[background rectangle/.style={fill=black},
                     % show background rectangle] 
  \pgftransformscale{0.35}
    % Create some counters for holding the Fibonacci numbers
    \newcounter{a}
    \newcounter{b}
    \newcounter{temp}

    % Initialize the counters
    \setcounter{a}{0}
    \setcounter{b}{1}

    % The spiral will start at the origin
    \coordinate (0) at (0,0);

    % This loop defines the number of turns in the spiral. Note that we
    % will have to be careful not to overflow our counters or make the
    % spiral too large for TeX to handle. This is easy to do as the
    % Fibonacci sequence grows exponentially.
    \foreach \i in {1,...,18}
    {
      % Get the "name" of the last point on the spiral
      \pgfmathsetmacro{\lastpoint}{\i-1}

      % Compute the angle for this turn of the spiral
%      \pgfmathsetmacro{\startangle}{mod(\i-1,4) * 90}
      \pgfmathsetmacro{\startangle}{mod(\i-1,4) * -90}

      % Draw this turn of the spiral and remember the point where we end 
%      \draw[white] (\lastpoint) arc 
      \draw (\lastpoint) arc 
%        (\startangle : \startangle + 90 : \value{b}/10.0pt) coordinate (\i);
        (\startangle : \startangle - 90 : \value{b}/10.0pt) coordinate (\i);

     % Compute the next Fibonacci number
      \setcounter{temp}{\value{b}}
      \addtocounter{b}{\value{a}}
      \setcounter{a}{\value{temp}}
   }

   % Add some framing for the spiral while at the same time not "boxing"
   % it in. Note that to put a square around each turn of the spiral we
   % could have just used the command \draw[white] (\lastpoint)
   % rectangle (\i); after drawing each turn in the loop above.
   \foreach \i in {1,3,...,17}
   {
     \pgfmathsetmacro{\lastpoint}{\i-1}
%     \draw[white] (\lastpoint) -| (\i);
     \draw[color=lightgray] (\lastpoint) -| (\i);
   }

   \foreach \i in {2,4,...,16}
   {
     \pgfmathsetmacro{\lastpoint}{\i-1}
%     \draw[white] (\lastpoint) |- (\i);
     \draw[color=lightgray] (\lastpoint) |- (\i);
   }

%   \draw[white] (17) -- (17 |- 18);
   \draw[color=lightgray] (17) -- (17 |- 18);
 
%   % Add some text displaying the formula for the Fibonacci numbers
%   \node(eq) at ($(18) + (2.5,1)$) 
%     [white,text width = 2cm,font=\fontsize{8}{8}\selectfont] {
%     \begin{displaymath}
%       f(n) = \left\{
%         \begin{array}{lr}
%           0 & \text{~~if } n = 0\\
%           1 & \text{~~if } n = 1\\
%           f(n-1) + f(n-2) & \text{~~if } n \geq 2\\
%        \end{array}
%       \right.
%     \end{displaymath}
%    };
  \end{tikzpicture}
}
  \caption{A spiral drawn inside Fibonacci rectangles and a golden spiral drawn inside golden rectangles.}
  \label{fig.numthry:goldenspiral}
\end{figure}
%%%%%%%%%%%%%%%%%%%% end rogue code %%%%%%%%%%%%%%%%%%%%%%%

Recall that the errors were

! LaTeX Error: No counter 'a' defined.

! LaTeX Error: No counter 'b' defined.

! LaTeX Error: No counter 'temp' defined.

Also recall that in the preamble I declare

\usetikzlibrary{decorations.pathreplacing}  % load tikz decorations library
\usetikzlibrary{calc}  % load the tikz calc library

But I do not know how to fix the code.  Any suggestions on fixing this piece of code would be appreciated.  Thanks.


> ------------------------------
> 
> Message: 7
> Date: Sat, 18 Dec 2010 20:33:40 -0700
> From: Don Green Dragon <fergdc at Shaw.ca>
> 
> According to George Gratzer's book "More Math into LaTeX", on page 4 he states:
> 
> "The name of a LaTeX source file should be one word (no spaces, no special characters), and end with .tex."
> 
>> From your error messages, it appears that you have a source file (for example) <ch.geom.tex> (without < and >) and that first occurrence of '.' may be the culprit. Each of the error messages appears to be complaining about an \include line.
> 
> Did you try the suggestion made by Ross Moore?

I replaced all the extra '.' in the filenames with '_'.  So, e.g., "ch.numthry.tex" is now "ch_numthry.tex".  Thanks.

Thank you all again.

---John.
(who receives the digest)

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