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ma-thesis/src/thesis/chapters/3_fault_tolerant_qec.tex

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\chapter{Fault Tolerant QEC}
\section{Fault Tolerance}
\section{Noise Models}
\subsection{Depolarizing Channel}
\subsection{Phenomenological Noise}
\subsection{Circuit-Level Noise}
\section{Detector Error Models}
\subsection{Measurement Syndrome Matrix}
\subsection{Detector Error Matrix}
\subsection{Detector Error Models}
\section{Practical Considerations}
\subsection{Practical Methodology}
\subsection{Stim}
\begin{figure}[t]
\centering
\newcommand{\xerr}{\gate[style={fill=KITblue!50}]{\phantom{1}}}
\newcommand{\xyzerr}{\gate[style={
draw=black,
fill=KITred,
path picture={
% tex-fmt: off
\fill[KITblue!60]
($(path picture bounding box.south west)+(0,0)$)
-- ($(path picture bounding box.north west)+(0,0)$)
-- ($(path picture bounding box.north west)+(0.28,0)$)
-- cycle;
\fill[KITorange!60]
($(path picture bounding box.north east)+(0,0)$)
-- ($(path picture bounding box.south east)+(0,0)$)
-- ($(path picture bounding box.south east)+(-0.28,0)$)
-- cycle;
\fill[KITred!60]
($(path picture bounding box.north east)+(0,0)$)
-- ($(path picture bounding box.south east)+(-0.28,0)$)
-- ($(path picture bounding box.south west)+(0,0)$)
-- ($(path picture bounding box.north west)+(0.28,0)$)
-- cycle;
% tex-fmt: on
}
}]{\phantom{1}}}
\begin{subfigure}{0.48\textwidth}
\centering
% tex-fmt: off
\begin{quantikz}[row sep=4mm, column sep=4mm]
& \xyzerr & \ctrl{3} & & & & & \\
\lstick{$\ket{\psi}$} & \xyzerr & & \ctrl{2} & \ctrl{3} & & & \\
& \xyzerr & & & & \ctrl{2} & & \\
\lstick{$\ket{0}_{\text{A}_1}$} & & \targ{} & \targ{} & & & \meter{} & \setwiretype{c} \\
\lstick{$\ket{0}_{\text{A}_2}$} & & & & \targ{} & \targ{} & \meter{} & \setwiretype{c}
\end{quantikz}
% tex-fmt: on
\caption{Depolarizing channel.}
\end{subfigure}%
\begin{subfigure}{0.48\textwidth}
\centering
% tex-fmt: off
\begin{quantikz}[row sep=4mm, column sep=4mm]
& \xerr & \ctrl{3} & & & & & & \\
\lstick{$\ket{\psi}$} & \xerr & & \ctrl{2} & \ctrl{3} & & & & \\
& \xerr & & & & \ctrl{2} & & & \\
\lstick{$\ket{0}_{\text{A}_1}$} & & \targ{} & \targ{} & & & \xerr & \meter{} & \setwiretype{c} \\
\lstick{$\ket{0}_{\text{A}_2}$} & & & & \targ{} & \targ{} & \xerr & \meter{} & \setwiretype{c}
\end{quantikz}
% tex-fmt: on
\caption{Phenomenological noise.}
\end{subfigure}
\vspace*{3mm}
\centering
\begin{subfigure}[c]{0.75\textwidth}
\centering
% tex-fmt: off
\begin{quantikz}[row sep=4mm, column sep=2mm]
& \xyzerr & \ctrl{3} & \xyzerr \wire[d][3]{q} & & & & & & & & & \\
\lstick{$\ket{\psi}$} & \xyzerr & & & \ctrl{2} & \xyzerr \wire[d][2]{q} & \ctrl{3} & \xyzerr \wire[d][3]{q} & & & & & \\
& \xyzerr & & & & & & & \ctrl{2} & \xyzerr \wire[d][2]{q} & & & \\
\lstick{$\ket{0}_{\text{A}_1}$} & \xyzerr & \targ{} & \xyzerr & \targ{} & \xyzerr & & & & & \xerr & \meter{} & \setwiretype{c} \\
\lstick{$\ket{0}_{\text{A}_2}$} & \xyzerr & & & & & \targ{} & \xyzerr & \targ{} & \xyzerr & \xerr & \meter{} & \setwiretype{c}
\end{quantikz}
% tex-fmt: on
\caption{Circuit-level noise.}
\end{subfigure}%
\hfill%
\begin{subfigure}[c]{0.25\textwidth}
\centering
% tex-fmt: off
\begin{quantikz}[row sep=4mm, column sep=2mm]
\setwiretype{n} & \xerr & \gate[style={right, draw=none, xshift=-15mm}]{\text{X error}} \\
\setwiretype{n} & \xyzerr & \gate[style={right, draw=none, xshift=-15mm}]{\text{X,Z, or Y error}} \\
\setwiretype{n} & \gate{\phantom{1}}\wire[d][1]{q} & \gate[style={right, draw=none, xshift=-15mm},2]{\text{Correlated error}} \\
\setwiretype{n} & \gate{\phantom{1}} &
\end{quantikz}
% tex-fmt: on
\end{subfigure}
\caption{Types of noise models.}
\label{fig:Types of noise models.}
\end{figure}
\begin{figure}[t]
\centering
\begin{tikzpicture}
\node[rectangle, draw, fill=orange!20, minimum
height=2cm, minimum width=2.5cm, align=left] at (0,0)
(internal) {Internal\\ Errors};
\node[signal, draw, fill=orange!20, minimum height=2cm,
minimum width=2.5cm, align=left, signal pointer angle=140]
at (-2.45, 0) (input) {Input\\ Errors};
\node at (1.97,0) {\huge =};
\node[rectangle, draw, fill=orange!20, minimum height=2cm,
minimum width=2.5cm, align=left] at (4,0) (output)
{Output\\ Errors};
\node[above] at (input.north) {\small Input State};
\node[above] at (internal.north) {\small QEC};
\node[above] at (output.north) {\small Output State};
\end{tikzpicture}
\caption{Sources of error in a fault-tolerant \ac{qec} system.}
\end{figure}
\begin{figure}[t]
\centering
\begin{minipage}{0.3\textwidth}
\centering
\begin{tikzpicture}
\node{$%
\bm{\Omega} =
\begin{pmatrix}
1 & 1 & 0 \\
0 & 1 & 1 \\
1 & 1 & 0 \\
0 & 1 & 1 \\
1 & 1 & 0 \\
0 & 1 & 1
\end{pmatrix}%
$
};
\draw [
line width=1pt,
decorate,
decoration={brace,mirror,amplitude=3mm,raise=5mm}
]
(1,0.55) -- (1,1.4)
node[midway,right,xshift=10mm]{$\text{SE}_1$};
\draw [
line width=1pt,
decorate,
decoration={brace,mirror,amplitude=3mm,raise=5mm}
]
(1,-0.4) -- (1,0.45)
node[midway,right,xshift=10mm]{$\text{SE}_2\hspace{2mm},$};
\draw [
line width=1pt,
decorate,
decoration={brace,mirror,amplitude=3mm,raise=5mm}
]
(1,-1.38) -- (1,-0.5)
node[midway,right,xshift=10mm]{$\text{SE}_3$};
\end{tikzpicture}
\end{minipage}%
\begin{minipage}{0.3\textwidth}
\centering
\vspace*{-6mm}
\begin{gather*}
\bm{s} \in \text{span} \mleft\{ \bm{\Omega} \mright\}
\end{gather*}
\end{minipage}
\newcommand{\preperr}[1]{
\gate[style={fill=orange!20}]{\scriptstyle #1}
}
\vspace*{10mm}
\begin{quantikz}[
row sep=4mm, column sep=4mm,
wire types={q,q,q,q,q,n,n,n,n},
execute at end picture={
\draw [
line width=1pt,
decorate,
decoration={brace,amplitude=3mm,raise=9mm}
]
(\tikzcdmatrixname-4-19.north east)
--
(\tikzcdmatrixname-5-19.south east)
node[midway,right,xshift=14mm]{$\text{SE}_1$};
\draw [
line width=1pt,
decorate,
decoration={brace,amplitude=3mm,raise=9mm}
]
(\tikzcdmatrixname-6-19.north east)
--
(\tikzcdmatrixname-7-19.south east)
node[midway,right,xshift=14mm]{$\text{SE}_2$};
\draw [
line width=1pt,
decorate,
decoration={brace,amplitude=3mm,raise=9mm}
]
(\tikzcdmatrixname-8-19.north east)
--
(\tikzcdmatrixname-9-19.south east)
node[midway,right,xshift=14mm]{$\text{SE}_3$};
}
]
% tex-fmt: off
\lstick[3]{$\ket{\psi}$} & \preperr{E_0} & \ctrl{3} & & & & & & \ctrl{5} & & & & & & \ctrl{7} & & & & & \\
& \preperr{E_1} & & \ctrl{2} & \ctrl{3} & & & & & \ctrl{4} & \ctrl{5} & & & & & \ctrl{6} & \ctrl{7} & & & \\
& \preperr{E_2} & & & & \ctrl{2} & & & & & & \ctrl{4} & & & & & & \ctrl{6} & & \\
\lstick{$\ket{0}_{\text{A}_1}$} & & \targ{} & \targ{} & & & & & & & & & & & & & & & \meter{} & \setwiretype{c} \\
\lstick{$\ket{0}_{\text{A}_2}$} & & & & \targ{} & \targ{} & & & & & & & & & & & & & \meter{} & \setwiretype{c} \\
& & & & & & \lstick{$\ket{0}_{\text{A}_3}$} & \setwiretype{q} & \targ{} & \targ{} & & & & & & & & & \meter{} & \setwiretype{c} \\
& & & & & & \lstick{$\ket{0}_{\text{A}_4}$} & \setwiretype{q} & & & \targ{} & \targ{} & & & & & & & \meter{} & \setwiretype{c} \\
& & & & & & & & & & & & \lstick{$\ket{0}_{\text{A}_5}$} & \setwiretype{q} & \targ{} & \targ{} & & & \meter{} & \setwiretype{c} \\
& & & & & & & & & & & & \lstick{$\ket{0}_{\text{A}_6}$} & \setwiretype{q} & & & \targ{} & \targ{} & \meter{} & \setwiretype{c}
% tex-fmt: on
\end{quantikz}
\caption{
Repeated syndrome extraction circuit for the two-qubit
repetition code under bit flip noise.
}
\end{figure}
\begin{figure}[t]
\begin{gather*}
\hspace*{-33.3mm}%
\begin{array}{c}
E_6 \\
\downarrow
\end{array}
\end{gather*}
\vspace*{-8mm}
\begin{gather*}
\bm{\Omega} =
\left(
\begin{array}{
cccccc%
>{\columncolor{red!20}}c%
cccccccc
}
1 & 1 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 0
& 0 & 0 & 0 & 0 & 0 \\
0 & 1 & 1 & 0 & 1 & 0 & 0 & 0 & 0 & 0
& 0 & 0 & 0 & 0 & 0 \\
1 & 1 & 0 & 0 & 0 & 1 & 1 & 0 & 1 & 0
& 0 & 0 & 0 & 0 & 0 \\
0 & 1 & 1 & 0 & 0 & 0 & 1 & 1 & 0 & 1
& 0 & 0 & 0 & 0 & 0 \\
1 & 1 & 0 & 0 & 0 & 1 & 1 & 0 & 0 & 0
& 1 & 1 & 0 & 1 & 0 \\
0 & 1 & 1 & 0 & 0 & 0 & 1 & 1 & 0 & 0
& 0 & 1 & 1 & 0 & 1
\end{array}
\right),
\hspace*{7mm}
\bm{s} \in \text{span} \mleft\{
\bm{\Omega} \mright\}
\end{gather*}
\vspace*{10mm}
\newcommand{\preperr}[1]{
\gate[style={fill=orange!20}]{\scriptstyle #1}
}
\newcommand{\measerr}{\gate[style={fill=blue!20}]{\phantom{1}}}
\newcommand{\noise}{
\gate[style={noisy}]{\text{\small X}}%
\setwiretype{n}%
\wire[l][1]{q}
}
\newcommand{\redwire}[1]{
\wire[r][#1][style={draw=red, line width=1.5pt}]{q}
}
\newcommand{\redtarg}{
\targ[style={draw=red}]{}%
\setwiretype{n}%
\wire[l][1]{q}
}
\newcommand{\redctrl}[1]{
\ctrl[style={draw=red,fill=red,line width=1.5pt}]{#1}
}
\newcommand{\redmeter}{\meter[style={draw=red,fill=red!20}]{}}
\tikzset{
noisy/.style={
starburst,
starburst point height=2.5mm,
fill=red!25, draw=red!85!black,
line width=1.5pt,
inner xsep=-2pt, inner ysep=-2pt
},
}
\centering
\scalebox{0.9}{
% tex-fmt: off
\begin{quantikz}[row sep=4mm, column sep=4mm, wire types={q,q,q,q,q,n,n,n,n}]
\lstick[3]{$\ket{\psi}$} & \preperr{E_0} & \ctrl{3} & & & & \preperr{E_5} & & \ctrl{5} & & & & \preperr{E_{10}} & & \ctrl{7} & & & & & & \\
& \preperr{E_1} & & \ctrl{2} & \ctrl{3} & & \noise\redwire{14} & & & \redctrl{4} & \redctrl{5} & & \preperr{E_{11}} & & & \redctrl{6} & \redctrl{7} & & & & \\
& \preperr{E_2} & & & & \ctrl{2} & \preperr{E_7} & & & & & \ctrl{4} & \preperr{E_{12}} & & & & & \ctrl{6} & & & \\
\lstick{$\ket{0}_{\text{A}_1}$} & & \targ{} & \targ{} & & & & & & & & & & & & & & & \preperr{E_3} & \meter{} & \setwiretype{c} \\
\lstick{$\ket{0}_{\text{A}_2}$} & & & & \targ{} & \targ{} & & & & & & & & & & & & & \preperr{E_4} & \meter{} & \setwiretype{c} \\
& & & & & & \lstick{$\ket{0}_{\text{A}_3}$} & \setwiretype{q} & \targ{} & \redtarg\redwire{10} & & & & & & & & & \preperr{E_8} & \redmeter\wire[r][1][style={draw=red,double, line width=1.5pt}]{q} & \setwiretype{n} \\
& & & & & & \lstick{$\ket{0}_{\text{A}_4}$} & \setwiretype{q} & & & \redtarg\redwire{9} & \targ{} & & & & & & & \preperr{E_9} & \redmeter\wire[r][1][style={draw=red,double, line width=1.5pt}]{q} & \setwiretype{n} \\
& & & & & & & & & & & & \lstick{$\ket{0}_{\text{A}_5}$} & \setwiretype{q} & \targ{} & \redtarg\redwire{4} & & & \preperr{E_{13}} & \redmeter\wire[r][1][style={draw=red,double, line width=1.5pt}]{q} & \setwiretype{n} \\
& & & & & & & & & & & & \lstick{$\ket{0}_{\text{A}_6}$} & \setwiretype{q} & & & \redtarg\redwire{3} & \targ{} & \preperr{E_{14}} & \redmeter\wire[r][1][style={draw=red,double, line width=1.5pt}]{q} & \setwiretype{n}
\end{quantikz}
% tex-fmt: on
}
\caption{
Repeated syndrome extraction circuit for the two-qubit
repetition code under phenomenological noise.
}
\end{figure}
\begin{figure}[t]
\centering
\hspace*{-5mm}
\begin{minipage}{0.42\textwidth}
\newcommand{\redwire}[1]{
\wire[r][#1][style={draw=red, line width=1.5pt, double}]{q}
}
\newcommand{\inwire}{
\wire[l][1][style={draw=red, line width=1.5pt}]{q}
}
\newcommand{\redtarg}{
\targ[style={draw=red,line width=1.5pt}]{}%
\setwiretype{n}%
}
\newcommand{\redctrl}[1]{
\ctrl[style={draw=red,fill=red, line width=1.5pt}]{0}%
\wire[d][#1][style={draw=red, line width=1.5pt, double}]{q}
}
\newcommand{\redmeter}{\meter[style={draw=red,fill=red!20}]{}}
\newcommand{\redgate}[1]{\gate[style={draw=red,fill=red!20}]{\textcolor{red}{#1}}}
\scalebox{0.9}{
% tex-fmt: off
\begin{quantikz}[row sep=4mm, column sep=4mm, wire types={n,n,n,n,n,n}]
& \meter{}\wire[l][1]{q}\wire[r][1]{c} & \setwiretype{c} & & & \ctrl[vertical wire=c]{2} & & \gate{D_1} \\
& \meter{}\wire[l][1]{q}\wire[r][1]{c} & \setwiretype{c} & & & & \ctrl[vertical wire=c]{2} & \gate{D_2} \\
& \redmeter{}\inwire\redwire{6} & & \redctrl{2} & & \targ{} & & \redgate{D_3} \\
& \redmeter{}\inwire\redwire{6} & & & \redctrl{2} & & \targ{} & \redgate{D_4} \\
& \redmeter{}\inwire\redwire{2} & & \redtarg\wire[r][4]{c} & & & & \gate{D_5} \\
& \redmeter{}\inwire\redwire{3} & & & \redtarg\wire[r][3]{c} & & & \gate{D_6}
\end{quantikz}
% tex-fmt: on
}
\end{minipage}%
\begin{minipage}{0.56\textwidth}
\newcommand\cc{\cellcolor{blue!20}}
\begin{align*}
\bm{H} =
% tex-fmt: off
\left(\begin{array}{ccccccccccccccc}
1 & 1 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 \\
0 & 1 & 1 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 & 0 \\
\cc{0} & \cc{0} & \cc{0} & \cc{1} & \cc{0} & 1 & 1 & 0 & 1 & 0 & 0 & 0 & 0 & 0 & 0 \\
\cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{1} & 0 & 1 & 1 & 0 & 1 & 0 & 0 & 0 & 0 & 0 \\
\cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{1} & \cc{0} & 1 & 1 & 0 & 1 & 0 \\
\cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{0} & \cc{1} & 0 & 1 & 1 & 0 & 1
\end{array}\right)
% tex-fmt: on
\end{align*}
\end{minipage}
\caption{Construction of the detectors from the measurements.}
\label{fig:Construction of the detectors from the measurements}
\end{figure}
\begin{figure}[t]
\centering
\hspace*{-114mm}%
\begin{tikzpicture}
\draw[decorate, decoration={brace, amplitude=10pt}, line width=1pt]
(0,0) -- (3.1,0) node[midway, above=4mm] {Commit region};
\end{tikzpicture}
\centering
\includegraphics[scale=0.75]{res/72_bb_dem.pdf}
\vspace*{-25.3mm}
\hspace*{-98mm}%
\begin{tikzpicture}
\draw[{Latex}-{Latex}, line width=.7pt] (0, -0.75mm) -- (0, 5mm);
\draw[line width=1pt] (-1mm,-0.75mm) -- (3mm,-0.75mm);
\draw[line width=1pt] (-1mm,5mm) -- (3mm,5mm);
\node[left] at (-2mm,2.125mm) {$\sim W$};
\draw[{Latex}-{Latex}, line width=.3pt] (6.5cm,1.6mm) -- (6.5cm,5mm);
\draw[line width=1pt] (6.5cm,4.9mm) -- (6.5cm,7mm);
\node[above] at (6.5cm,7mm) {$\sim F$};
\end{tikzpicture}
\vspace*{10mm}
\caption{
Visualization of the windowing process on the detector
error matrix.
}
\label{fig:windowing_pcm}
\end{figure}
\begin{figure}[t]
\centering
\tikzset{
VN/.style={
circle, fill=KITgreen, minimum width=1mm, minimum height=1mm,
},
CN/.style={
rectangle, fill=KITblue, minimum width=1mm, minimum height=1mm,
},
}
\begin{tikzpicture}[node distance = 5mm]
\node[VN] (vn00) {};
\node[VN, below = of vn00] (vn01) {};
\node[VN, below = of vn01] (vn02) {};
\node[VN, below = of vn02] (vn03) {};
\node[VN, below = of vn03] (vn04) {};
\coordinate (temp) at ($(vn01)!0.5!(vn02)$);
\node[CN, left =10mm of temp] (cn00) {};
\node[CN, below = of cn00] (cn01) {};
\draw (vn00) -- (cn00);
\draw (vn01) -- (cn00);
\draw (vn03) -- (cn00);
\draw (vn01) -- (cn01);
\draw (vn02) -- (cn01);
\draw (vn04) -- (cn01);
\foreach \i in {1,2,3,4} {
\pgfmathtruncatemacro{\prev}{\i-1}
\node[VN, right = 25mm of vn\prev 0] (vn\i0) {};
\node[VN, below = of vn\i0] (vn\i1) {};
\node[VN, below = of vn\i1] (vn\i2) {};
\node[VN, below = of vn\i2] (vn\i3) {};
\node[VN, below = of vn\i3] (vn\i4) {};
\coordinate (temp) at ($(vn\i1)!0.5!(vn\i2)$);
\node[CN, left = 10mm of temp] (cn\i0) {};
\node[CN, below = of cn\i0] (cn\i1) {};
\draw (vn\i0) -- (cn\i0);
\draw (vn\i1) -- (cn\i0);
\draw (vn\i3) -- (cn\i0);
\draw (vn\i1) -- (cn\i1);
\draw (vn\i2) -- (cn\i1);
\draw (vn\i4) -- (cn\i1);
}
\foreach \i in {1,2,3,4} {
\pgfmathtruncatemacro{\prev}{\i-1}
\draw (vn\prev 3) -- (cn\i 0);
\draw (vn\prev 4) -- (cn\i 1);
}
\node[
draw, inner sep=5mm,line width=1pt,
fit=(vn00)(vn04)(cn00)(cn01)(vn20)(vn24)(cn20)(cn21)
]
(box1) {};
\node[
draw, dashed, inner sep=5mm, inner ysep=8mm,line width=1pt,
fit=(vn10)(vn14)(cn10)(cn11)(vn30)(vn34)(cn30)(cn31)
]
(box2) {};
% Marker for W on the bottom
\draw[line width=1pt]
([yshift=-5mm, line width=1pt]box1.south west) -- ++(0,-4mm)
coordinate (dim1l);
\draw[line width=1pt]
([yshift=-5mm]box1.south east) -- ++(0,-4mm)
coordinate (dim1r);
\draw[{Latex}-{Latex}, line width=1pt]
([yshift=1mm]dim1l) -- ([yshift=1mm]dim1r)
node[midway, below=2pt] {$W$};
% Marker for F on top
\draw[line width=1pt]
([yshift=3mm]box2.north west) -- ++(0,4mm)
coordinate (dim3l);
\draw[line width=1pt]
([yshift=3mm]box2.north west -| box1.north west) -- ++(0,4mm)
coordinate (dim3r);
\draw[{Latex}-{Latex}, line width=1pt]
([yshift=-1mm]dim3l) -- ([yshift=-1mm]dim3r)
node[midway, above=2pt] {$F$};
% Arrow on the top right
\draw[-{Latex}, line width=1pt]
([yshift=8mm] box1.north east) -- ++(28mm,0);
\end{tikzpicture}
\caption{Visualization of the windowing process on the Tanner graph.}
\label{fig:windowing_tanner}
\end{figure}
\begin{figure}[t]
\centering
\tikzset{
VN/.style={
circle, fill=KITgreen, minimum width=1mm, minimum height=1mm,
},
CN/.style={
rectangle, fill=KITblue, minimum width=1mm, minimum height=1mm,
},
}
\begin{tikzpicture}[node distance = 5mm]
\node[VN] (vn00) {};
\node[VN, below = of vn00] (vn01) {};
\node[VN, below = of vn01] (vn02) {};
\node[VN, below = of vn02] (vn03) {};
\node[VN, below = of vn03] (vn04) {};
\coordinate (temp) at ($(vn01)!0.5!(vn02)$);
\node[CN, left =10mm of temp] (cn00) {};
\node[CN, below = of cn00] (cn01) {};
\draw (vn00) -- (cn00);
\draw (vn01) -- (cn00);
\draw (vn03) -- (cn00);
\draw (vn01) -- (cn01);
\draw (vn02) -- (cn01);
\draw (vn04) -- (cn01);
\foreach \i in {1,2,3,4} {
\pgfmathtruncatemacro{\prev}{\i-1}
\node[VN, right = 25mm of vn\prev 0] (vn\i0) {};
\node[VN, below = of vn\i0] (vn\i1) {};
\node[VN, below = of vn\i1] (vn\i2) {};
\node[VN, below = of vn\i2] (vn\i3) {};
\node[VN, below = of vn\i3] (vn\i4) {};
\coordinate (temp) at ($(vn\i1)!0.5!(vn\i2)$);
\node[CN, left = 10mm of temp] (cn\i0) {};
\node[CN, below = of cn\i0] (cn\i1) {};
\draw (vn\i0) -- (cn\i0);
\draw (vn\i1) -- (cn\i0);
\draw (vn\i3) -- (cn\i0);
\draw (vn\i1) -- (cn\i1);
\draw (vn\i2) -- (cn\i1);
\draw (vn\i4) -- (cn\i1);
}
\foreach \i in {1,2,3,4} {
\pgfmathtruncatemacro{\prev}{\i-1}
\draw (vn\prev 3) -- (cn\i 0);
\draw (vn\prev 4) -- (cn\i 1);
}
\node[
draw, inner sep=5mm,line width=1pt,
fit=(vn00)(vn04)(cn00)(cn01)(vn20)(vn24)(cn20)(cn21)
]
(box1) {};
\node[
draw, dashed, inner sep=5mm, inner ysep=8mm,line width=1pt,
fit=(vn10)(vn14)(cn10)(cn11)(vn30)(vn34)(cn30)(cn31)
]
(box2) {};
\draw[KITorange, line width=2pt] (cn10) -- (vn10);
\draw[KITorange, line width=2pt] (cn10) -- (vn11);
\draw[KITorange, line width=2pt] (cn10) -- (vn13);
\draw[KITorange, line width=2pt] (cn11) -- (vn11);
\draw[KITorange, line width=2pt] (cn11) -- (vn12);
\draw[KITorange, line width=2pt] (cn11) -- (vn14);
\draw[KITorange, line width=2pt] (vn13) -- (cn20);
\draw[KITorange, line width=2pt] (vn14) -- (cn21);
\draw[KITorange, line width=2pt] (cn20) -- (vn20);
\draw[KITorange, line width=2pt] (cn20) -- (vn21);
\draw[KITorange, line width=2pt] (cn20) -- (vn23);
\draw[KITorange, line width=2pt] (cn21) -- (vn21);
\draw[KITorange, line width=2pt] (cn21) -- (vn22);
\draw[KITorange, line width=2pt] (cn21) -- (vn24);
% Marker for W on the bottom
\draw[line width=1pt]
([yshift=-5mm, line width=1pt]box1.south west) -- ++(0,-4mm)
coordinate (dim1l);
\draw[line width=1pt]
([yshift=-5mm]box1.south east) -- ++(0,-4mm)
coordinate (dim1r);
\draw[{Latex}-{Latex}, line width=1pt]
([yshift=1mm]dim1l) -- ([yshift=1mm]dim1r)
node[midway, below=2pt] {$W$};
% Marker for F on top
\draw[line width=1pt]
([yshift=3mm]box2.north west) -- ++(0,4mm)
coordinate (dim3l);
\draw[line width=1pt]
([yshift=3mm]box2.north west -| box1.north west) -- ++(0,4mm)
coordinate (dim3r);
\draw[{Latex}-{Latex}, line width=1pt]
([yshift=-1mm]dim3l) -- ([yshift=-1mm]dim3r)
node[midway, above=2pt] {$F$};
% Arrow on the top right
\draw[-{Latex}, line width=1pt]
([yshift=8mm] box1.north east) -- ++(28mm,0);
\end{tikzpicture}
\caption{
Visualization of the messages used for the
initialization of the next window.
}
\label{fig:messages_tanner}
\end{figure}
\begin{figure}[t]
\centering
\tikzset{
VN/.style={
circle, fill=KITgreen, minimum width=1mm, minimum height=1mm,
},
CN/.style={
rectangle, fill=KITblue, minimum width=1mm, minimum height=1mm,
},
}
\begin{tikzpicture}[node distance = 5mm]
\node[VN] (vn00) {};
\node[VN, below = of vn00] (vn01) {};
\node[VN, below = of vn01] (vn02) {};
\node[VN, below = of vn02] (vn03) {};
\node[VN, below = of vn03] (vn04) {};
\coordinate (temp) at ($(vn01)!0.5!(vn02)$);
\node[CN, left =10mm of temp] (cn00) {};
\node[CN, below = of cn00] (cn01) {};
\draw (vn00) -- (cn00);
\draw (vn01) -- (cn00);
\draw (vn03) -- (cn00);
\draw (vn01) -- (cn01);
\draw (vn02) -- (cn01);
\draw (vn04) -- (cn01);
\foreach \i in {1,2,3,4} {
\pgfmathtruncatemacro{\prev}{\i-1}
\node[VN, right = 25mm of vn\prev 0] (vn\i0) {};
\node[VN, below = of vn\i0] (vn\i1) {};
\node[VN, below = of vn\i1] (vn\i2) {};
\node[VN, below = of vn\i2] (vn\i3) {};
\node[VN, below = of vn\i3] (vn\i4) {};
\coordinate (temp) at ($(vn\i1)!0.5!(vn\i2)$);
\node[CN, left = 10mm of temp] (cn\i0) {};
\node[CN, below = of cn\i0] (cn\i1) {};
\draw (vn\i0) -- (cn\i0);
\draw (vn\i1) -- (cn\i0);
\draw (vn\i3) -- (cn\i0);
\draw (vn\i1) -- (cn\i1);
\draw (vn\i2) -- (cn\i1);
\draw (vn\i4) -- (cn\i1);
}
\foreach \i in {1,2,3,4} {
\pgfmathtruncatemacro{\prev}{\i-1}
\draw (vn\prev 3) -- (cn\i 0);
\draw (vn\prev 4) -- (cn\i 1);
}
\node[
draw, inner sep=5mm,line width=1pt,
fit=(vn00)(vn04)(cn00)(cn01)(vn20)(vn24)(cn20)(cn21)
]
(box1) {};
\node[
draw, dashed, inner sep=5mm, inner ysep=8mm,line width=1pt,
fit=(vn10)(vn14)(cn10)(cn11)(vn30)(vn34)(cn30)(cn31)
]
(box2) {};
\draw[KITorange, line width=2pt] (cn10) -- (vn10);
\draw[KITorange, line width=2pt] (cn10) -- (vn11);
\draw[KITorange, line width=2pt] (cn10) -- (vn13);
\draw[KITorange, line width=2pt] (cn11) -- (vn11);
\draw[KITorange, line width=2pt] (cn11) -- (vn12);
\draw[KITorange, line width=2pt] (cn11) -- (vn14);
\draw[KITorange, line width=2pt] (vn13) -- (cn20);
\draw[KITorange, line width=2pt] (vn14) -- (cn21);
\draw[KITorange, line width=2pt] (cn20) -- (vn20);
\draw[KITorange, line width=2pt] (cn20) -- (vn21);
\draw[KITorange, line width=2pt] (cn20) -- (vn23);
\draw[KITorange, line width=2pt] (cn21) -- (vn21);
\draw[KITorange, line width=2pt] (cn21) -- (vn22);
\draw[KITorange, line width=2pt] (cn21) -- (vn24);
\node[VN, draw=KITorange, fill=KITorange] at (vn10) {};
\node[VN, draw=KITorange, fill=KITorange] at (vn11) {};
\node[VN, draw=KITorange, fill=KITorange] at (vn12) {};
\node[VN, draw=KITorange, fill=KITorange] at (vn13) {};
\node[VN, draw=KITorange, fill=KITorange] at (vn14) {};
\node[VN, draw=KITorange, fill=KITorange] at (vn20) {};
\node[VN, draw=KITorange, fill=KITorange] at (vn21) {};
\node[VN, draw=KITorange, fill=KITorange] at (vn22) {};
\node[VN, draw=KITorange, fill=KITorange] at (vn23) {};
\node[VN, draw=KITorange, fill=KITorange] at (vn24) {};
% Marker for W on the bottom
\draw[line width=1pt]
([yshift=-5mm, line width=1pt]box1.south west) -- ++(0,-4mm)
coordinate (dim1l);
\draw[line width=1pt]
([yshift=-5mm]box1.south east) -- ++(0,-4mm)
coordinate (dim1r);
\draw[{Latex}-{Latex}, line width=1pt]
([yshift=1mm]dim1l) -- ([yshift=1mm]dim1r)
node[midway, below=2pt] {$W$};
% Marker for F on top
\draw[line width=1pt]
([yshift=3mm]box2.north west) -- ++(0,4mm)
coordinate (dim3l);
\draw[line width=1pt]
([yshift=3mm]box2.north west -| box1.north west) -- ++(0,4mm)
coordinate (dim3r);
\draw[{Latex}-{Latex}, line width=1pt]
([yshift=-1mm]dim3l) -- ([yshift=-1mm]dim3r)
node[midway, above=2pt] {$F$};
% Arrow on the top right
\draw[-{Latex}, line width=1pt]
([yshift=8mm] box1.north east) -- ++(28mm,0);
\end{tikzpicture}
\caption{
Visualization of the messages and decimation information used for the
initialization of the next window.
}
\label{fig:messages_decimation_tanner}
\end{figure}