Recent changes to 230: bug when trying to store `\pgfplotstablegetrowsof` with `\pgfmathsetmacro`

#230 bug when trying to store `\pgfplotstablegetrowsof` with `\pgfmathsetmacro`

Stefan Pinnow — Sat, 30 Nov 2019 20:29:42 -0000

Description has changed:

Diff:

--- old
+++ new
@@ -19,74 +19,76 @@

 MWE:

-    % used PGFPlots v1.16
-        % first put the data to an external file or a table,
-        % so it can be handled by the `pgfplotstable&#39; package
-        \begin{filecontents}{data.txt}
-            0   0
-            1   1
-            2   2
-            3   3
-            4   4
-        \end{filecontents}
-    \documentclass[border=5pt]{standalone}
-    \usepackage{pgfplots}
-    \usepackage{pgfplotstable}
-        \usetikzlibrary{
-            fpu,
-            positioning,    % &lt;-- for debugging nodes only
+~~~latex
+% used PGFPlots v1.16
+    % first put the data to an external file or a table,
+    % so it can be handled by the `pgfplotstable&#39; package
+    \begin{filecontents}{data.txt}
+        0   0
+        1   1
+        2   2
+        3   3
+        4   4
+    \end{filecontents}
+\documentclass[border=5pt]{standalone}
+\usepackage{pgfplots}
+\usepackage{pgfplotstable}
+    \usetikzlibrary{
+        fpu,
+        positioning,    % &lt;-- for debugging nodes only
+    }
+    \pgfplotsset{
+        compat=1.16,
+    }
+\begin{document}
+    \begin{tikzpicture}
+        % to be sure that no numbers are interpreted as zero, activate `fpu&#39;
+        % library
+        \tikzset{
+            fpu=true,
         }
-        \pgfplotsset{
-            compat=1.16,
+            %%% find `xmin&#39; and `xmax&#39;
+            % for that first sort the table after the x values
+            \pgfplotstablesort{\SortedTable}{data.txt}
+            % then one can directly extract `xmin&#39;
+            \pgfplotstablegetelem{0}{[index] 0}\of\SortedTable
+                \pgfmathsetmacro{\xmin}{\pgfplotsretval}
+            %% now extract `xmax&#39;
+            % for that we first need to extract the number of rows in the table
+            \pgfplotstablegetrowsof{\SortedTable}
+                \pgfmathsetmacro{\NoOfRows}{\pgfplotsretval-1}
+            % then we can extract the last entry in the sorted table
+            % (I think because of a bug this doesn&#39;t work so one has to
+            %  enter the index manually)
+            \pgfplotstablegetelem{\NoOfRows}{[index] 0}\of\SortedTable
+%            \pgfplotstablegetelem{4}{[index] 0}\of\SortedTable
+                \pgfmathsetmacro{\xmax}{\pgfplotsretval}
+
+        \tikzset{
+            fpu=false,
         }
-    \begin{document}
-        \begin{tikzpicture}
-            % to be sure that no numbers are interpreted as zero, activate `fpu&#39;
-            % library
-            \tikzset{
-                fpu=true,
-            }
-                %%% find `xmin&#39; and `xmax&#39;
-                % for that first sort the table after the x values
-                \pgfplotstablesort{\SortedTable}{data.txt}
-                % then one can directly extract `xmin&#39;
-                \pgfplotstablegetelem{0}{[index] 0}\of\SortedTable
-                    \pgfmathsetmacro{\xmin}{\pgfplotsretval}
-                %% now extract `xmax&#39;
-                % for that we first need to extract the number of rows in the table
-                \pgfplotstablegetrowsof{\SortedTable}
-                    \pgfmathsetmacro{\NoOfRows}{\pgfplotsretval-1}
-                % then we can extract the last entry in the sorted table
-                % (I think because of a bug this doesn&#39;t work so one has to
-                %  enter the index manually)
-                \pgfplotstablegetelem{\NoOfRows}{[index] 0}\of\SortedTable
-    %            \pgfplotstablegetelem{4}{[index] 0}\of\SortedTable
-                    \pgfmathsetmacro{\xmax}{\pgfplotsretval}

-            \tikzset{
-                fpu=false,
-            }
+        \begin{axis}[
+            % add the extra ticks from the extracted data
+            extra x ticks={
+                \xmin,
+                \xmax
+            },
+            % just to make sure these are the extra ticks, draw them red
+            extra x tick style={
+                text=red,
+            },
+        ]
+            \addplot +[black, mark options=fill=black] table {data.txt};

-            \begin{axis}[
-                % add the extra ticks from the extracted data
-                extra x ticks={
-                    \xmin,
-                    \xmax
-                },
-                % just to make sure these are the extra ticks, draw them red
-                extra x tick style={
-                    text=red,
-                },
-            ]
-                \addplot +[black, mark options=fill=black] table {data.txt};
-
-                % for debugging show the value of `xmax&#39;
-                \node [fill=black!25,anchor=north west]  (a) at (rel axis cs:0.02,0.98)
-                    {Rows = \pgfmathprintnumber{\NoOfRows}};
-                \node [fill=black!25,below=1pt of a.south west,anchor=north west]
-                    {xmax = \pgfmathprintnumber{\xmax}};
-            \end{axis}
-        \end{tikzpicture}
-    \end{document}
+            % for debugging show the value of `xmax&#39;
+            \node [fill=black!25,anchor=north west]  (a) at (rel axis cs:0.02,0.98)
+                {Rows = \pgfmathprintnumber{\NoOfRows}};
+            \node [fill=black!25,below=1pt of a.south west,anchor=north west]
+                {xmax = \pgfmathprintnumber{\xmax}};
+        \end{axis}
+    \end{tikzpicture}
+\end{document}
+~~~

 which results in the attached picture.

bug when trying to store `\pgfplotstablegetrowsof` with `\pgfmathsetmacro`

Stefan Pinnow — Sat, 30 Nov 2019 20:28:07 -0000

Actually this is a bug that originally was reported in the TikZ/pgf tracker (https://sourceforge.net/p/pgf/bugs/383/, https://github.com/pgf-tikz/pgf/issues/382) but should most likely have been reported here. So I am "repeating" it here with some minor modifications/updates. I also provide an MWE at the end.

For simplicity here I only copy some lines of emails in German which should act as a reminder for Christian.

My email:

[...] könntest du mal einen kurzen Blick auf
https://tex.stackexchange.com/revisions/299200/3
werfen und mir sagen, ob es ein Bug ist, dass ich \NoOfRows nicht in \pgfplotstablegetelem verwenden kann. [...]

His answer:

[...] das mit \NoOfRows ist eine Mischung aus der komplizierten Nutzung der FPU engine und einem fehlenden sanity check (=bug).

Was passiert ist dass \NoOfRows auf 1Y4.0e0 gesetzt wird, was soviel heisst wie "+ 4.0 * 10^0". Als Zeilennummer interpretiert scheint der aber nur die "1" genommen zu haben und den Rest stillschweigend weggeworfen zu haben. [...]

MWE:

% used PGFPlots v1.16
    % first put the data to an external file or a table,
    % so it can be handled by the `pgfplotstable' package
    \begin{filecontents}{data.txt}
        0   0
        1   1
        2   2
        3   3
        4   4
    \end{filecontents}
\documentclass[border=5pt]{standalone}
\usepackage{pgfplots}
\usepackage{pgfplotstable}
    \usetikzlibrary{
        fpu,
        positioning,    % <-- for debugging nodes only
    }
    \pgfplotsset{
        compat=1.16,
    }
\begin{document}
    \begin{tikzpicture}
        % to be sure that no numbers are interpreted as zero, activate `fpu'
        % library
        \tikzset{
            fpu=true,
        }
            %%% find `xmin' and `xmax'
            % for that first sort the table after the x values
            \pgfplotstablesort{\SortedTable}{data.txt}
            % then one can directly extract `xmin'
            \pgfplotstablegetelem{0}{[index] 0}\of\SortedTable
                \pgfmathsetmacro{\xmin}{\pgfplotsretval}
            %% now extract `xmax'
            % for that we first need to extract the number of rows in the table
            \pgfplotstablegetrowsof{\SortedTable}
                \pgfmathsetmacro{\NoOfRows}{\pgfplotsretval-1}
            % then we can extract the last entry in the sorted table
            % (I think because of a bug this doesn't work so one has to
            %  enter the index manually)
            \pgfplotstablegetelem{\NoOfRows}{[index] 0}\of\SortedTable
%            \pgfplotstablegetelem{4}{[index] 0}\of\SortedTable
                \pgfmathsetmacro{\xmax}{\pgfplotsretval}

        \tikzset{
            fpu=false,
        }

        \begin{axis}[
            % add the extra ticks from the extracted data
            extra x ticks={
                \xmin,
                \xmax
            },
            % just to make sure these are the extra ticks, draw them red
            extra x tick style={
                text=red,
            },
        ]
            \addplot +[black, mark options=fill=black] table {data.txt};

            % for debugging show the value of `xmax'
            \node [fill=black!25,anchor=north west]  (a) at (rel axis cs:0.02,0.98)
                {Rows = \pgfmathprintnumber{\NoOfRows}};
            \node [fill=black!25,below=1pt of a.south west,anchor=north west]
                {xmax = \pgfmathprintnumber{\xmax}};
        \end{axis}
    \end{tikzpicture}
\end{document}

which results in the attached picture.

bug when trying to store `\pgfplotstablegetrowsof` with `\pgfmathsetmacro`

Stefan Pinnow — Sat, 30 Nov 2019 20:28:07 -0000

Ticket 230 has been modified: bug when trying to store \pgfplotstablegetrowsof with \pgfmathsetmacro
Edited By: Stefan Pinnow (mo-gul)
Description updated:
--- description-old

+++ description-new

@@ -19,74 +19,76 @@

MWE:

% used PGFPlots v1.16
% first put the data to an external file or a table,
% so it can be handled by the `pgfplotstable' package
\begin{filecontents}{data.txt}
0 0
1 1
2 2
3 3
4 4
\end{filecontents}
\documentclass[border=5pt]
\usepackage{pgfplots}
\usepackage{pgfplotstable}
\usetikzlibrary{
fpu,
positioning, % <-- for debugging nodes only
+~~~latex
+% used PGFPlots v1.16
% first put the data to an external file or a table,
% so it can be handled by the `pgfplotstable' package
\begin{filecontents}{data.txt}
0 0
1 1
2 2
3 3
4 4
\end{filecontents}
+\documentclass[border=5pt]
+\usepackage{pgfplots}
+\usepackage{pgfplotstable}
\usetikzlibrary{
fpu,
positioning, % <-- for debugging nodes only
}
\pgfplotsset{
compat=1.16,
}
+\begin{document}
\begin{tikzpicture}
% to be sure that no numbers are interpreted as zero, activate `fpu'
% library
\tikzset{
fpu=true,
}
\pgfplotsset{
compat=1.16,
%%% find xmin' andxmax'
% for that first sort the table after the x values
\pgfplotstablesort{\SortedTable}{data.txt}
% then one can directly extract `xmin'
\pgfplotstablegetelem{0}{[index] 0}\of\SortedTable
\pgfmathsetmacro{\xmin}{\pgfplotsretval}
%% now extract `xmax'
% for that we first need to extract the number of rows in the table
\pgfplotstablegetrowsof{\SortedTable}
\pgfmathsetmacro{\NoOfRows}{\pgfplotsretval-1}
% then we can extract the last entry in the sorted table
% (I think because of a bug this doesn't work so one has to
% enter the index manually)
\pgfplotstablegetelem{\NoOfRows}{[index] 0}\of\SortedTable
+% \pgfplotstablegetelem{4}{[index] 0}\of\SortedTable
\pgfmathsetmacro{\xmax}{\pgfplotsretval}
+
\tikzset{
fpu=false,
}
\begin{document}
\begin{tikzpicture}
% to be sure that no numbers are interpreted as zero, activate `fpu'
% library
\tikzset{
fpu=true,
}
%%% find xmin' andxmax'
% for that first sort the table after the x values
\pgfplotstablesort{\SortedTable}{data.txt}
% then one can directly extract `xmin'
\pgfplotstablegetelem{0}{[index] 0}\of\SortedTable
\pgfmathsetmacro{\xmin}{\pgfplotsretval}
%% now extract `xmax'
% for that we first need to extract the number of rows in the table
\pgfplotstablegetrowsof{\SortedTable}
\pgfmathsetmacro{\NoOfRows}{\pgfplotsretval-1}
% then we can extract the last entry in the sorted table
% (I think because of a bug this doesn't work so one has to
% enter the index manually)
\pgfplotstablegetelem{\NoOfRows}{[index] 0}\of\SortedTable
% \pgfplotstablegetelem{4}{[index] 0}\of\SortedTable
\pgfmathsetmacro{\xmax}{\pgfplotsretval}
\tikzset{
fpu=false,
}
\begin{axis}[
% add the extra ticks from the extracted data
extra x ticks={
\xmin,
\xmax
},
% just to make sure these are the extra ticks, draw them red
extra x tick style={
text=red,
},
]
\addplot +[black, mark options=fill=black] table {data.txt};
\begin{axis}[
% add the extra ticks from the extracted data
extra x ticks={
\xmin,
\xmax
},
% just to make sure these are the extra ticks, draw them red
extra x tick style={
text=red,
},
]
\addplot +[black, mark options=fill=black] table {data.txt};
% for debugging show the value of `xmax'
\node [fill=black!25,anchor=north west] (a) at (rel axis cs:0.02,0.98)
{Rows = \pgfmathprintnumber{\NoOfRows}};
\node [fill=black!25,below=1pt of a.south west,anchor=north west]
{xmax = \pgfmathprintnumber{\xmax}};
\end{axis}
\end{tikzpicture}
\end{document}
% for debugging show the value of `xmax'
\node [fill=black!25,anchor=north west] (a) at (rel axis cs:0.02,0.98)
{Rows = \pgfmathprintnumber{\NoOfRows}};
\node [fill=black!25,below=1pt of a.south west,anchor=north west]
{xmax = \pgfmathprintnumber{\xmax}};
\end{axis}
\end{tikzpicture}
+\end{document}
+~~~

which results in the attached picture.