How to construct a confusion matrix in LaTeX?

Question

A confusion matrix looks like:

Is there an easy way to do the same using LaTeX?

Otherwise I could just create a diagram with any software.

Answer 1

Here's a solution without TikZ:

\documentclass{article}
\usepackage{array}
\usepackage{multirow}

\newcommand\MyBox[2]{
  \fbox{\lower0.75cm
    \vbox to 1.7cm{\vfil
      \hbox to 1.7cm{\hfil\parbox{1.4cm}{#1\\#2}\hfil}
      \vfil}%
  }%
}

\begin{document}

\noindent
\renewcommand\arraystretch{1.5}
\setlength\tabcolsep{0pt}
\begin{tabular}{c >{\bfseries}r @{\hspace{0.7em}}c @{\hspace{0.4em}}c @{\hspace{0.7em}}l}
  \multirow{10}{*}{\parbox{1.1cm}{\bfseries\raggedleft actual\\ value}} & 
    & \multicolumn{2}{c}{\bfseries Prediction outcome} & \\
  & & \bfseries p & \bfseries n & \bfseries total \\
  & p$'$ & \MyBox{True}{Positive} & \MyBox{False}{Negative} & P$'$ \\[2.4em]
  & n$'$ & \MyBox{False}{Positive} & \MyBox{True}{Negative} & N$'$ \\
  & total & P & N &
\end{tabular}

\end{document}

In a comment it has been requested to rotate one of the labels; this can be easily done using \rotatebox from graphicx:

\documentclass{article}
\usepackage{array}
\usepackage{graphicx}
\usepackage{multirow}

\newcommand\MyBox[2]{
  \fbox{\lower0.75cm
    \vbox to 1.7cm{\vfil
      \hbox to 1.7cm{\hfil\parbox{1.4cm}{#1\\#2}\hfil}
      \vfil}%
  }%
}

\begin{document}

\noindent
\renewcommand\arraystretch{1.5}
\setlength\tabcolsep{0pt}
\begin{tabular}{c >{\bfseries}r @{\hspace{0.7em}}c @{\hspace{0.4em}}c @{\hspace{0.7em}}l}
  \multirow{10}{*}{\rotatebox{90}{\parbox{1.1cm}{\bfseries\centering actual\\ value}}} & 
    & \multicolumn{2}{c}{\bfseries Prediction outcome} & \\
  & & \bfseries p & \bfseries n & \bfseries total \\
  & p$'$ & \MyBox{True}{Positive} & \MyBox{False}{Negative} & P$'$ \\[2.4em]
  & n$'$ & \MyBox{False}{Positive} & \MyBox{True}{Negative} & N$'$ \\
  & total & P & N &
\end{tabular}

\end{document}

Answer 2

Here is some LaTeX code I used to produce related tables for a tutorial. It might get you close to what you're looking for, although you'll probably want to change the layout.

\begin{tabular}{l|l|c|c|c}
\multicolumn{2}{c}{}&\multicolumn{2}{c}{True diagnosis}&\\
\cline{3-4}
\multicolumn{2}{c|}{}&Positive&Negative&\multicolumn{1}{c}{Total}\\
\cline{2-4}
\multirow{2}{*}{Screening test}& Positive & $a$ & $b$ & $a+b$\\
\cline{2-4}
& Negative & $c$ & $d$ & $c+d$\\
\cline{2-4}
\multicolumn{1}{c}{} & \multicolumn{1}{c}{Total} & \multicolumn{1}{c}{$a+c$} & \multicolumn{    1}{c}{$b+d$} & \multicolumn{1}{c}{$N$}\\
\end{tabular}

% need the pifont package
\begin{tabular}{l|l|>{\columncolor{gray!20}}l|l|l}
%\begin{tabular}{l|l|l|l|l}                                                                  
\multicolumn{2}{c}{}&\multicolumn{2}{c}{True diagnosis}&\\
\cline{3-4}
\multicolumn{2}{c|}{}&\multicolumn{1}{c|}{Positive}&\multicolumn{1}{c|}{Negative}&\multicolu    mn{1}{c}{}\\
%\cline{2-4}                                                                                 
\hhline{~|---}
\multirow{2}{*}{Screening test}& Positive & TP & FP ($\alpha$) &\ding{214} PPV\\
%\cline{2-4}                                                                                 
\hhline{~|---}
& Negative & FN ($\beta$) & TN & \ding{214} NPV\\
%\cline{2-4}                                                                                 
\hhline{~|---}
\multicolumn{1}{c}{} & \multicolumn{1}{c}{} &
\multicolumn{1}{c}{\multirow{2}{*}{\parbox{2em}{\vskip1ex\ding{215}\\ Se}}} & \multicolumn{1    }{c}{\multirow{2}{*}{\parbox{2em}{\vskip1ex\ding{215}\\ Sp}}} &\multicolumn{1}{c}{}\\
\end{tabular}

Answer 3

It's quite easy making such a thing with TikZ, once you get the hang of it.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{positioning}
\begin{document}
\begin{tikzpicture}[
box/.style={draw,rectangle,minimum size=2cm,text width=1.5cm,align=left}]
\matrix (conmat) [row sep=.1cm,column sep=.1cm] {
\node (tpos) [box,
    label=left:\( \mathbf{p'} \),
    label=above:\( \mathbf{p} \),
    ] {True \\ positive};
&
\node (fneg) [box,
    label=above:\textbf{n},
    label=above right:\textbf{total},
    label=right:\( \mathrm{P}' \)] {False \\ negative};
\\
\node (fpos) [box,
    label=left:\( \mathbf{n'} \),
    label=below left:\textbf{total},
    label=below:P] {False \\ positive};
&
\node (tneg) [box,
    label=right:\( \mathrm{N}' \),
    label=below:N] {True \\ negative};
\\
};
\node [left=.05cm of conmat,text width=1.5cm,align=right] {\textbf{actual \\ value}};
\node [above=.05cm of conmat] {\textbf{prediction outcome}};
\end{tikzpicture}
\end{document}

To rotate actual value you can replace

\node [left=.05cm of conmat,text width=1.5cm,align=right] {\textbf{actual \\ value}};

with

 \node [rotate=90,left=.05cm of conmat,anchor=center,text width=1.5cm,align=center] {\textbf{actual \\ value}};

Answer 4

To create a color confusion matrix like this:

You can use the following code.

\documentclass[english]{article}
\usepackage[T1]{fontenc}
\usepackage[latin9]{inputenc}
\usepackage{babel}
\usepackage[table]{xcolor}
\usepackage{collcell}
\usepackage{hhline}
\usepackage{pgf}
\usepackage{multirow}

\def\colorModel{hsb} %You can use rgb or hsb

\newcommand\ColCell[1]{
  \pgfmathparse{#1<50?1:0}  %Threshold for changing the font color into the cells
    \ifnum\pgfmathresult=0\relax\color{white}\fi
  \pgfmathsetmacro\compA{0}      %Component R or H
  \pgfmathsetmacro\compB{#1/100} %Component G or S
  \pgfmathsetmacro\compC{1}      %Component B or B
  \edef\x{\noexpand\centering\noexpand\cellcolor[\colorModel]{\compA,\compB,\compC}}\x #1
  } 
\newcolumntype{E}{>{\collectcell\ColCell}m{0.4cm}<{\endcollectcell}}  %Cell width
\newcommand*\rot{\rotatebox{90}}

\begin{document}
\newcommand\items{3}   %Number of classes
\arrayrulecolor{white} %Table line colors
\noindent\begin{tabular}{cc*{\items}{|E}|}
\multicolumn{1}{c}{} &\multicolumn{1}{c}{} &\multicolumn{\items}{c}{Predicted} \\ \hhline{~*\items{|-}|}
\multicolumn{1}{c}{} & 
\multicolumn{1}{c}{} & 
\multicolumn{1}{c}{\rot{Class A}} & 
\multicolumn{1}{c}{\rot{Class B}} & 
\multicolumn{1}{c}{\rot{Class C}} \\ \hhline{~*\items{|-}|}
\multirow{\items}{*}{\rotatebox{90}{Actual}} 
&Class A  & 100   & 0  & 10   \\ \hhline{~*\items{|-}|}
&Class B  & 10   & 80  & 10   \\ \hhline{~*\items{|-}|}
&Class C  & 30   & 0   & 70   \\ \hhline{~*\items{|-}|}
\end{tabular}

\end{document}

You can control the color ranges using the HSB or RGB models and the formulas in compA, compB and compC.

So, for "Autum" (red-yellow) range use:

\pgfmathsetmacro\compA{#1/600} %Component R or H
\pgfmathsetmacro\compB{1} %Component G or S
\pgfmathsetmacro\compC{1} %Component B or B

For "Cool" (cyan-magenta) range set rgb for color model and use:

\pgfmathsetmacro\compA{#1/100}   %Component R or H
\pgfmathsetmacro\compB{1-#1/100} %Component G or S
\pgfmathsetmacro\compC{1}        %Component B or B

For "Black-red" range use:

\pgfmathsetmacro\compA{0} %Component R or H
\pgfmathsetmacro\compB{1} %Component G or S
\pgfmathsetmacro\compC{#1/100} %Component B or B

For "Jet" range use:

\pgfmathsetmacro\compA{0.6666-#1/150} %Component R or H
\pgfmathsetmacro\compB{1}             %Component G or S
\pgfmathsetmacro\compC{1}             %Component B or B

For "Cooper" range use:

\pgfmathsetmacro\compA{0.08+#1/5000} %Component R or H
\pgfmathsetmacro\compB{0.7}          %Component G or S
\pgfmathsetmacro\compC{#1/100}       %Component B or B

For "Gray" range use:

\pgfmathsetmacro\compA{0}      %Component R or H
\pgfmathsetmacro\compB{0} %Component G or S
\pgfmathsetmacro\compC{#1/100}      %Component B or B

Answer 5

\documentclass[conference]{IEEEtran}
\usepackage[center]{caption}
\usepackage{multirow}
\usepackage{textcomp}
\usepackage{graphicx}
\begin{document}
\begin{table}[!ht]
    \centering
    \caption{Confusion Matrix}
    \label{sa}
    \renewcommand{\arraystretch}{3}
    \begin{tabular}{ll|l|l|l|l|l|}
        
\multicolumn{2}{c}{}&   \multicolumn{5}{c}{Predicted Classes}\\
        \multicolumn{2}{c}{}&\multicolumn{5}{c}{{\rotatebox[origin=c]{0}{Fear}
            } {\rotatebox[origin=c]{0}{Happy}
            } {\rotatebox[origin=c]{0}{Love}
            } {\rotatebox[origin=c]{0}{Sad}
            } {\rotatebox[origin=c]{0}{Violence}
        }}\\
        \cline{3-7}
        \multirow{5}{*}{{\rotatebox[origin=c]{90}{Actual Classes}
        }} & 
        Fear&0.55 & 0.16 &0.04 & 0.30 & 0.02  \\ \cline{3-7}
        &   Happy&0.13 & 0.75 &0.02 & 0.11 & 0.02 \\ \cline{3-7}
        &   Love&0.03 & 0.01 &0.91 & 0.00 & 0.01 \\ \cline{3-7}
        &   Sad&0.25 & 0.07 &0.01 & 0.58 & 0.01 \\ \cline{3-7}
        &   Violence&0.04 & 0.01 &0.02 & 0.00 & 0.94 \\ \cline{3-7}
    \end{tabular}
\end{table}
\end{document}

Answer 6

Follows a solution used for a paper about a neural network based classifier. In the example, there are 5 classes and the confusion matrix is a good way to illustrate the network performance. The tikz code is not universal, but it accepts easily some customization.

\documentclass[tikz]{standalone}
\usepackage{ifthen}
\usetikzlibrary{matrix,calc}

\begin{document}

%The matrix in numbers
%Horizontal target class
%Vertical output class
\def\myConfMat{{
{1620,  30,  60,   0,  0},  %row 1
{   0,1390, 110,  80,100},  %row 2
{   0,  40,1090,  40,  0},  %row 3
{   0, 350,  30,1020, 90},  %row 4
{   0,  50,  30, 300,800},  %row 5
}}

\def\classNames{{"A","B","C","D","E"}} %class names. Adapt at will

\def\numClasses{5} %number of classes. Could be automatic, but you can change it for tests.

\def\myScale{1.5} % 1.5 is a good scale. Values under 1 may need smaller fonts!
\begin{tikzpicture}[
    scale = \myScale,
    %font={\scriptsize}, %for smaller scales, even \tiny may be useful
    ]

\tikzset{vertical label/.style={rotate=90,anchor=east}}   % usable styles for below
\tikzset{diagonal label/.style={rotate=45,anchor=north east}}

\foreach \y in {1,...,\numClasses} %loop vertical starting on top
{
    % Add class name on the left
    \node [anchor=east] at (0.4,-\y) {\pgfmathparse{\classNames[\y-1]}\pgfmathresult}; 
    
    \foreach \x in {1,...,\numClasses}  %loop horizontal starting on left
    {
%---- Start of automatic calculation of totSamples for the column ------------   
    \def\totSamples{0}
    \foreach \ll in {1,...,\numClasses}
    {
        \pgfmathparse{\myConfMat[\ll-1][\x-1]}   %fetch next element
        \xdef\totSamples{\totSamples+\pgfmathresult} %accumulate it with previous sum
        %must use \xdef fro global effect otherwise lost in foreach loop!
    }
    \pgfmathparse{\totSamples} \xdef\totSamples{\pgfmathresult}  % put the final sum in variable
%---- End of automatic calculation of totSamples ----------------
    
    \begin{scope}[shift={(\x,-\y)}]
        \def\mVal{\myConfMat[\y-1][\x-1]} % The value at index y,x (-1 because of zero indexing)
        \pgfmathtruncatemacro{\r}{\mVal}   %
        \pgfmathtruncatemacro{\p}{round(\r/\totSamples*100)}
        \coordinate (C) at (0,0);
        \ifthenelse{\p<50}{\def\txtcol{black}}{\def\txtcol{white}} %decide text color for contrast
        \node[
            draw,                 %draw lines
            text=\txtcol,         %text color (automatic for better contrast)
            align=center,         %align text inside cells (also for wrapping)
            fill=black!\p,        %intensity of fill (can change base color)
            minimum size=\myScale*10mm,    %cell size to fit the scale and integer dimensions (in cm)
            inner sep=0,          %remove all inner gaps to save space in small scales
            ] (C) {\r\\\p\%};     %text to put in cell (adapt at will)
        %Now if last vertical class add its label at the bottom
        \ifthenelse{\y=\numClasses}{
        \node [] at ($(C)-(0,0.75)$) % can use vertical or diagonal label as option
        {\pgfmathparse{\classNames[\x-1]}\pgfmathresult};}{}
    \end{scope}
    }
}
%Now add x and y labels on suitable coordinates
\coordinate (yaxis) at (-0.3,0.5-\numClasses/2);  %must adapt if class labels are wider!
\coordinate (xaxis) at (0.5+\numClasses/2, -\numClasses-1.25); %id. for non horizontal labels!
\node [vertical label] at (yaxis) {Output Class};
\node []               at (xaxis) {Target Class};
\end{tikzpicture}

\end{document}

Answer 7

The line:

\multicolumn{1}{c}{} & \multicolumn{1}{c}{Total} & \multicolumn{1}{c}{$a+c$} & \multicolumn{\
1}{c}{$b+d$} & \multicolumn{1}{c}{$N$}\\

needs to be corrected to

\multicolumn{1}{c}{} & \multicolumn{1}{c}{Total} & \multicolumn{1}{c}{$a+c$} & \multicolumn{ 
1}{c}{$b+d$} & \multicolumn{1}{c}{$N$}\\

in order to compile...