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authorCarlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au>2012-09-05 10:25:19 +1000
committerCarlo Zancanaro <carlo@pc-4w14-0.cs.usyd.edu.au>2012-09-05 10:25:19 +1000
commit608cf2e6a2ccc967e82b2b7a9693fd0bafb778fb (patch)
tree02a4f4136e50af3865df5acefc9174f73004c10a /tex/presentation/thomas/slides.tex
parent35d53c78a4afd739d1246db486f2703e44590eda (diff)
Delete a lot of tex stuff, better debug info
Some other stuff, too, I think. Oh well. No biggie!
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-\newcommand{\brighten}{\pos{0,0}{\begin{tikzpicture}[fill opacity=.5, opacity=.5]\pgfsetstrokecolor{white}\filldraw[fill=white] (0,0) rectangle (14,12);\end{tikzpicture}}}
-
-\newcommand{\stmtone}{(\vx_1,\vx_2) := (0,1)}
-\newcommand{\stmttwo}{\vx_1 \leq 8 ;\, (\vx_1,\vx_2) := (\vx_1 + 2, \vx_2 + 2)}
-
-%%%
-%%%
-%%%
-
-\title{{\bf Static Analysis \\ through \\Abstract Interpretation, \\Convex Optimization, and\\ Strategy Iteration}}
-
-\author{
- {\bf Thomas Martin Gawlitza${}^1$}
- \\[3pt]
- joint work with
- \\[3pt]
- {\bf Helmut Seidl${}^2$}
-}
-
-\institute{
- $\fourIdx{\text{{\large\bf 1}}}{}{}{}{\text{\includegraphics[height=15mm]{../logos/usyd.pdf}}}$
- \qquad\qquad
- $\fourIdx{\text{{\large\bf 2}}}{}{}{}{\text{\includegraphics[height=15mm]{../logos/TUM.pdf}}}$
-}
-
-\date{\bf SAPLING Meeting, November 2011}
-
-%%%
-%%%
-%%%
-
-\newcommand\partone{Abstract Interpretation using Zones}
-\newcommand\parttwo{Max-Strategy Iteration}
-\newcommand\partthree{Conclusion}
-
-\newcommand{\outline}[1]{
- \frame{\Large\bf
- \frametitle{Outline}
- \begin{enumerate}
- \item
- \ifthenelse{\equal{#1}{1}}%
- {\partone}%
- {\Grey{\partone}}
- \bigskip
- \bigskip
- \item
- \ifthenelse{\equal{#1}{2}}%
- {\bf \parttwo}%
- {\bf\Grey{\parttwo}}
- \bigskip
- \bigskip
- \item
- \ifthenelse{\equal{#1}{3}}%
- {\bf\partthree}%
- {\Grey{\partthree}}
- \end{enumerate}
- }
- \ifthenelse{\equal{#1}{1}}{\section{\partone}}{}
- \ifthenelse{\equal{#1}{2}}{\section{\parttwo}}{}
- \ifthenelse{\equal{#1}{3}}{\section{\partthree}}{}
-}
-
-%%%
-%%%
-%%%
-
-\section{Title}
-
-%%%
-
-\frame[plain]{\titlepage}
-
-%%%
-
-\outline{1}
-
-%%%
-
-\begin{frame}{Abstract Domain: {\bf Zones} (1/2)}
-\uncover<2->{
- \Green{\bf Goal}: \emph{Tight bounds} on the possible values of \emph{integer variables}
-
- \qquad\qquad (like $\vx_1 \leq 42, \; \vx_2 \leq 13$)
-
- \bigskip
- \qquad$\leadsto$ buffer overflows, worst-case execution times, etc.
-}
-
-\uncover<3->{
- \bigskip
- \Green{\bf Definition}:
- Invariants of the form
- \begin{align*}
- \bigwedge_\vx \vx \leq b_{\vx} \wedge \bigwedge_\vx -\vx \leq b_{-\vx} \wedge \bigwedge_{\vx,\vy} \vx - \vy \leq b_{\vx-\vy}
- \end{align*}
-
- That is:
- \emph{bounds} on \emph{variables} and
- \emph{differences of variables}.
-}
-
-\uncover<4->{
- \bigskip
- \Green{\bf Applications}:
-
- \smallskip
- Model-checking of timed automata \cite{DBLP:conf/eef/Yovine96,DBLP:conf/rtss/LarsenLPY97}
-
- \smallskip
- Static program analysis \cite{Sagiv01,DBLP:conf/pado/Mine01}
-}
-
-\end{frame}
-
-%%%
-
-\begin{frame}{Abstract Domain: {\bf Zones} (2/2)}
-\uncover<2->{
- \Green{\bf Our point of view}:
- Zones are special \emph{template polyhedra}
-
- \smallskip
- \qquad$\leadsto$ template polyhedra: \cite{DBLP:conf/vmcai/SankaranarayananSM05}
-}
-
-\uncover<3->{
- \bigskip
- \Green{\bf Given}:
- \emph{template constraint matrix} $T \in \{-1,0,1\}^{m\times n}$, where every row contains
- \emph{at most one $1$}, and
- \emph{at most one $-1$}.
- Then:
-\begin{align*}
- \gamma(b)
- &:=
- \{ x \in \Z^n \mid T x \leq b \}
- &&
- \text{for all } b \in \CZ^m
- \\
- \alpha(X)
- &:=
- \min \; \{ b \in \CZ^m \mid \gamma(b) \supseteq X \}
- &&
- \text{for all } X \subseteq \Z^n
-\end{align*}
-}
-
-\uncover<4->{
- \Green{\bf Example}:
- Let
- $
- T
- =
- \begin{pmatrix}
- 1 & 0 \\
- 0 & 1 \\
- -1 & 1
- \end{pmatrix}
- $.
- Then:
-
- $
- \gamma\left(
- \begin{pmatrix} 3 \\ 2 \\ 1 \end{pmatrix}
- \right)
- =
- \left\{
- \begin{pmatrix} \vx_1 \\ \vx_2 \end{pmatrix} \in \Z^2
- \mid
- T \begin{pmatrix} \vx_1 \\ \vx_2 \end{pmatrix}
- \leq
- \begin{pmatrix} 3 \\ 2 \\ 1 \end{pmatrix}
- \right\}
- =
- \begin{matrix}\mbox{\scalebox{0.5}{
- \begin{tikzpicture}[show background grid,scale=1]
- \filldraw[fill=lightgray,color=lightgray]
- (-1,-1) -- (0-1,1-1) -- (1,2) -- (3,2) -- (3,-1) -- (-1,-1);
- \draw[thick, ->] (-1,0) -- (4.2,0) node[right] {$\vx_1$-axis};
- \draw[thick, ->] (0,-1) -- (0,3.2) node[above] {$\vx_2$-axis};
- \draw[ultra thick] (-1,2) -- (4,2) node[above] {$\vx_2 \leq 2$};
- \draw[ultra thick] (-1,0) -- (2,3) node[above,xshift=2mm] {$\vx_2 \leq 1 {+} \vx_1$};
- \draw[ultra thick] (3,-1) -- (3,3) node[right] {$\vx_1 \leq 3$};
- \end{tikzpicture}}}\end{matrix}
- $
-}
-\end{frame}
-
-%%%
-
-\begin{frame}{Zone-based Static Program Analysis}
-\uncover<2->{
- \Green{\bf Goal}:
- Find minimal \emph{zones} that are \emph{invariants}
-}
-
-\uncover<3->{
- \bigskip
- \Green{\bf Example}:
- \begin{center}
-
- $
- \begin{matrix}\mbox{\scalebox{0.8}{\begin{tikzpicture}
- \node (start) [circle,draw] {$a$};
- \node (null) [coordinate,right of = start] {};
- \node (n1) [below of = start,circle,draw,yshift=-8mm]{$b$};
- \path[ultra thick,->] (null) edge [] node [right] {} (start);
- \path[ultra thick,->] (start) edge [] node [right,yshift=1mm] {$\stmtone$} (n1);
- \path[ultra thick,->] (n1) edge [loop right,out=35,in=-35, distance=20mm] node [right] {
- $\stmttwo$
- } (n1);
- \end{tikzpicture}}}\end{matrix}
- \qquad\quad
- T
- =
- \begin{pmatrix}
- 1 & 0 \\
- 0 & 1 \\
- -1 & 1
- \end{pmatrix}
- $
- \end{center}
-}
-
-\uncover<4->{
- \vspace*{-5mm}
- For program point $a$:
-
- \smallskip
- $
- \gamma \left(
- \begin{pmatrix} \infty \\ \infty \\ \infty \end{pmatrix}
- \right)
- =
- \left\{ 
- \begin{pmatrix} \vx_1\\\vx_2 \end{pmatrix}
- \mid
- \begin{pmatrix}
- 1 & 0 \\
- 0 & 1 \\
- -1 & 1
- \end{pmatrix}
- \begin{pmatrix} \vx_1\\\vx_2 \end{pmatrix}
- \leq
- \begin{pmatrix} \infty \\ \infty \\ \infty \end{pmatrix}
- \right\}
- $
-}
-
-\uncover<5->{
- \bigskip
- For program point $b$:
-
- \smallskip
- $
- \gamma \left(
- \begin{pmatrix} 10 \\ 11 \\ 1 \end{pmatrix}
- \right)
- =
- \left\{ 
- \begin{pmatrix} \vx_1\\\vx_2 \end{pmatrix}
- \mid
- \begin{pmatrix}
- 1 & 0 \\
- 0 & 1 \\
- -1 & 1
- \end{pmatrix}
- \begin{pmatrix} \vx_1\\\vx_2 \end{pmatrix}
- \leq
- \begin{pmatrix} 10 \\ 11 \\ 1 \end{pmatrix}
- \right\}
- $
-}
-\end{frame}
-
-%%%
-
-\begin{frame}{How Can We Compute {\bf Small} Zones?}
- \begin{enumerate}
- \item<2->
- À la \cite{Sagiv01,DBLP:conf/pado/Mine01}
-
- \smallskip
- Abstr.\ Interpr.\ / widening / narrowing à la \cite{DBLP:conf/popl/CousotC77}
-
- \smallskip
- \uncover<3->{\emph{Properties}:}
- \begin{itemize}
- \smallskip\item<4->
- Abstract transformers can be implemented in \emph{strongly polynomial time}
- (based on the Floyd-Warshall algorithm)
- \smallskip\item<5->
- \emph{Best} abstract transformers only for special classes of affine assignments
- (like $\vx = \vx + d$ and $\vx = \vy + d$).
- \smallskip\item<6->
- Computed zones are \emph{not} necessarily \emph{minimal}
- \end{itemize}
- \bigskip\item<7->
- À la \cite{DBLP:conf/csl/GawlitzaS07}
-
- \smallskip
- Abstr.\ Interpr.\ / strategy iteration for \emph{template polyhedra}
-
- \smallskip
- \uncover<8->{\emph{Properties}:}
- \begin{itemize}
- \smallskip\item<9->
- Computed the \emph{minimal} zones that are invariant
- \smallskip\item<10->
- Arbitrary affine assignments (like $\vx = c_1 \vx_1 + \cdots + c_k \vx_k + d$)
- \smallskip\item<11->
- Proves that the corresponding decision problem is in $\mathbf{coNP}$.
-
- \qquad (it is also at least as hard as mean payoff games)
- \smallskip\item<12->
- At most exp. many iterations, each of which can be performed in \emph{weakly polynomial time} through \emph{linear programming}.
- \end{itemize}
- \end{enumerate}
-\end{frame}
-
-%%%
-
-\begin{frame}{Obvious Question}
- \begin{center}
- \huge
- \uncover<2->{Can we do better?}
- \end{center}
-
- \begin{center}
-\uncover<3->{
- \bigskip
- \Green{\bf\huge Idea}
-
- \bigskip
- max-strategy improvement algorithm for \emph{template polyhedra}
-
- \vspace*{-2mm}
- \scalebox{2}{\rotatebox{-90}{$\leadsto$}}
-
- \smallskip
- max-strategy improvement algorithm for \emph{zones}
-}
-
-\uncover<4->{
- \bigskip
- \bigskip
- \Green{\bf\huge Hope}
-
- \bigskip
- improvement step in \emph{weakly} polynomial time
-
- \vspace*{-2mm}
- \scalebox{2}{\rotatebox{-90}{$\leadsto$}}
-
- \smallskip
- improvement step in \emph{strongly} polynomial time
-}
- \end{center}
-\end{frame}
-
-%%%
-
-\outline{2}
-
-%%%
-
-\begin{frame}{Abstract Transformers}
- \uncover<2->{
- \emph{Statements} %
- %
- \begin{align*}
- T \vx \leq c \; \wedge \; \vx' = A \vx + d
- \end{align*}
-}
-
-\uncover<3->{
- \emph{Collecting Semantics} %
- %
- \begin{align*}
- \sem{T \vx \leq c \; \wedge \; \vx' = A \vx + d} (X)
- =
- \{ x' \mid x \in X \wedge Tx \leq c \wedge x' = Ax+d \}
- \end{align*}
-}
-
-\uncover<4->{
- \emph{Abstract Semantics} %
- %
- \begin{align*}
- \sem{T \vx \leq c \; \wedge \; \vx' = A \vx + d}^\sharp (b)
- &= \alpha(\sem{T \vx \leq c \; \wedge \; \vx' = A \vx + d} (\gamma( b )))
- \end{align*}
-}
-\end{frame}
-
-%%%
-
-\begin{frame}{First Step: {\bf Constraint System} over $\CZ$}
-
- \pos{1,1.0}{
- $
- \begin{matrix}\mbox{\scalebox{1}{\begin{tikzpicture}
- \node (start) [circle,draw] {$a$};
- \node (null) [coordinate,right of = start] {};
- \node (n1) [below of = start,circle,draw,yshift=-8mm]{$b$};
- \uncover<2->{\path[ultra thick,->] (null) edge [] node [right] {} (start);}
- \uncover<6->{\path[ultra thick,->] (start) edge [] node [right,yshift=1mm] {$\stmtone$} (n1);}
- \uncover<10->{\path[ultra thick,->] (n1) edge [loop right,out=35,in=-35, distance=20mm] node [right]
- {$\stmttwo$} (n1);}
- \end{tikzpicture}}}\end{matrix}
- \qquad
- T
- =
- \begin{pmatrix}
- 1 & 0 \\
- 0 & 1 \\
- -1 & 1
- \end{pmatrix}
- $
- }
-
- \pos{0.3,4}{\Green{\bf Least Solution of}}
-
- \pos{0.3,4.5}{
- $
- \begin{array}{@{}r@{}l}
- \uncover<3->{\vb^a_{1} &\geq \infty \\}
- \uncover<4->{\vb^a_{2} &\geq \infty \\}
- \uncover<5->{\vb^a_{3} &\geq \infty}
- \\[5pt]
- \uncover<7->{\vb^b_{1} &\geq \pi_{1}(\sem{\stmtone}^\sharp (\vb^a_{1}, \vb^a_{2}, \vb^a_{3})) \\}
- \uncover<8->{\vb^b_{2} &\geq \pi_{2}(\sem{\stmtone}^\sharp (\vb^a_{1}, \vb^a_{2}, \vb^a_{3})) \\}
- \uncover<9->{\vb^b_{3} &\geq \pi_{3}(\sem{\stmtone}^\sharp (\vb^a_{1}, \vb^a_{2}, \vb^a_{3}))}
- \\[5pt]
- \uncover<11->{\vb^b_{1} &\geq \pi_{1}(\sem{\stmttwo}^\sharp (\vb^b_{1}, \vb^b_{2}, \vb^b_{3})) \\}
- \uncover<12->{\vb^b_{2} &\geq \pi_{2}(\sem{\stmttwo}^\sharp (\vb^b_{1}, \vb^b_{2}, \vb^b_{3})) \\}
- \uncover<13->{\vb^b_{3} &\geq \pi_{3}(\sem{\stmttwo}^\sharp (\vb^b_{1}, \vb^b_{2}, \vb^b_{3})) }
- \end{array}
- $
- }
-\end{frame}
-
-%%%
-
-\begin{frame}{Properties of the Abstract Semantics}
- \Green{\bf Observation}:
- %
- \only<1-10>{%
- \begin{align*}
- &\pi_{k}(\sem{T \vx \leq c \; \wedge \; \vx' = A \vx + d}^\sharp (b)) \\
- \uncover<2->{=\;& \pi_{k}( \alpha(\sem{T \vx \leq c \; \wedge \; \vx' = A \vx + d} (\gamma( b ))) ) \\}
- \uncover<3->{=\;& \pi_{k}( \alpha(\sem{T \vx \leq c \; \wedge \; \vx' = A \vx + d} ( \{ \vx \in \Z^n \mid T\vx \leq b \} )) ) \\}
- \uncover<4->{=\;& \pi_{k}( \alpha( \{ \vx' \mid \vx, \vx' \in \Z^n \;\wedge\; T \vx \leq b, c \; \wedge \; \vx' = A \vx + d \} ) ) \\}
- \uncover<5->{=\;& \pi_{k}( \alpha( \{ A \vx + d \mid \vx \in \Z^n \;\wedge\; T \vx \leq \min(b, c) \} ) ) \\}
- \uncover<6->{=\;& \sup \; \{ T_k(A \vx + d) \mid \vx \in \Z^n \;\wedge\; T \vx \leq \min(b, c) \} \\}
- \uncover<7->{=\;& T_k d + \sup \; \{ T_k A \vx \mid \vx \in \Z^n \;\wedge\; T \vx \leq \min ( b, c ) \} \\}
- \uncover<8->{=\;& T_k d + \sup \; \{ T_k A \vx \mid \vx \in \R^n \;\wedge\; T \vx \leq \min ( b, c ) \} \\}
- \uncover<9->{=\;& T_k d + \inf \; \{ (\min( b, c ))^\top \vy \mid \vy \in \R_{\geq 0}^n \wedge T^\top \vy = (T_1A)^\top \vy \} \\}
- \uncover<10->{=\;& T_k d + \inf \; \{ (\min( b, c ))^\top \vy \mid \vy \in \Z_{\geq 0}^n \wedge T^\top \vy = (T_1A)^\top \vy \} \\}
- \end{align*}%
- }%
- \only<11->{%
- \begin{align*}
- &\pi_{k}(\sem{T \vx \leq c \; \wedge \; \vx' = A \vx + d}^\sharp (b)) \\
- \uncover<10->{=\;& T_k d + \inf \; \{ (\min( b, c ))^\top \vy \mid \vy \in \Z_{\geq 0}^n \wedge T^\top \vy = (T_1A)^\top \vy \} \\}
- \end{align*}
- }%
-
- \uncover<12->{
- \Green{\bf Consequences}:
-
- \bigskip
- $\pi_k \circ \sem{T \vx \leq c \; \wedge \; \vx' = A \vx + d}^\sharp : \CZ^m \to \CZ$
- \begin{enumerate}
- \smallskip\item<13->
- is a point-wise \emph{minimum} of finitely many \emph{monotone} and \emph{affine} functions from the set $\CZ^M \to \CZ$.
- \smallskip\item<14->
- can be evaluated in \emph{strongly polynomial time}.
-
- \smallskip
- \qquad$\leadsto$ minimum cost flow network problem
-
- \qquad$\leadsto$ $\mathcal{O}( m \cdot \log m \cdot ( n + m \cdot \log m ))$
- \end{enumerate}
- }
-
-% \uncover<15>{
-% \bigskip
-% \Green{\bf So What?}
-% }
-\end{frame}
-
-%%%
-
-\begin{frame}{Minimum Cost Flow Network Problem}
- \begin{align*}
- \min \;\; b^\top \begin{pmatrix} \vy_1 \\ \vy_2 \\ \vy_3 \end{pmatrix}
- \qquad\qquad
- \\[10pt]
- %
- \begin{pmatrix}
- 1 & 0 & -1 \\
- 0 & 1 & 1\\
- -1 & -1 & 0
- \end{pmatrix}
- \begin{pmatrix} \vy_1 \\ \vy_2 \\ \vy_3 \end{pmatrix}
- &=
- \begin{pmatrix} c_1 \\ c_2 \\ c_3 \end{pmatrix}
- &
- \begin{pmatrix} \vy_1 \\ \vy_2 \\ \vy_3 \end{pmatrix}
- &\geq
- 0
- \end{align*}
-
- \bigskip
-
- \begin{center}
- $
- \begin{matrix}\mbox{\scalebox{1}{\begin{tikzpicture}
- \node (c1) [circle,draw] {$c_1$};
- \node (c2) [circle,draw,right of = c1, xshift=10mm] {$c_2$};
- \node (c3) [below of = c2,circle,draw,yshift=-8mm]{$c_3$};
- \uncover{\path[ultra thick,->] (c1) edge [] node [left] {$\vy_1$} (c3);}
- \uncover{\path[ultra thick,->] (c2) edge [] node [right] {$\vy_2$} (c3);}
- \uncover{\path[ultra thick,->] (c1) edge [] node [above] {$\vy_3$} (c2);}
- \end{tikzpicture}}}\end{matrix}
- $
- \end{center}
-
-\end{frame}
-
-%%%
-
-\begin{frame}{}
-\vfill
- \begin{center}
- \huge\bf And now?
- \end{center}
- \vfill
-\end{frame}
-
-%%%
-
-\begin{frame}{A Simple Example}
-\pos{0,1.3}{
- $
- \begin{array}{@{}p{8mm}@{\quad}r@{\,}l@{\qquad}r@{\,}l@{\quad}r@{\,}l@{\quad}}
- \centering $\Rot{\only<4-6>\neginfty\only<7-19>0\only<20->{42}}$
- & \uncover<1->{\vx_1^+ &\geq \neginfty & \vx_1^+ &\geq 0 \qquad \vx_1^+ \geq \vx_3^+ + 1 } \\[0.2mm]
- \centering $\Rot{\only<4-6>\neginfty\only<7->0}$
- & \uncover<1->{\vx_1^- &\geq \neginfty & \vx_1^- &\geq 0 \qquad \vx_1^- \geq \vx_3^- + (-1)} \\[0.2mm]
- \centering $\Rot{\only<4-10>\neginfty\only<11-19>0\only<20->{41}}$
- & \uncover<1->{\vx_2^+ &\geq \neginfty & \vx_2^+ &\geq (\vx_1^- \geq -41) \;?\; \min \{ \vx_1^+, 41 \} } \\[0.2mm]
- \centering $\Rot{\only<4-10>\neginfty\only<11->0}$
- & \uncover<1->{\vx_2^- &\geq \neginfty & \vx_2^- &\geq (\vx_1^- \geq -41) \;?\; \vx_1^-} \\[0.2mm]
- \centering $\Rot{\only<4-15>\neginfty\only<16-19>0\only<20->{41}}$
- & \uncover<1->{\vx_3^+ &\geq \neginfty & \vx_3^+ &\geq (\vx_2^- \geq -41 \;\&\; \vx_2^+ \geq 0 ) \;?\; \min \{ \vx_2^+, 41 \}} \\[0.2mm]
- \centering $\Rot{\only<4-15>\neginfty\only<16->0}$
- & \uncover<1->{\vx_3^- &\geq \neginfty & \vx_3^- &\geq (\vx_2^- \geq -41 \;\&\; \vx_2^+ \geq 0 ) \;?\; \min \{ \vx_2^-, 0 \} }
- \end{array}
- $}
-\pos{1,4.8}{\emph{Greatest Fixpoint Iteration:}}
-\pos{1,5.4}{
- $
- \begin{array}{|r||p{10mm}|p{10mm}|p{10mm}|p{10mm}|p{10mm}|p{10mm}|p{10mm}|@{}l@{}}
- & \centering 0
- & \centering 1
- & \centering 2
- & \centering 3
- & \centering 4
- & \centering 5
- & \centering 6
- & \\
- \hline
- \hline
- \vx_1^+
- & \centering $\infty$
- & \centering $\only<3>\neginfty\only<6,9-10,13-15>0\only<18-19>\infty$
- & \centering $\only<10,14-15>0\only<19>{42}$
- & \centering $\only<15>0$
- & \centering
- & \centering
- & \centering
- &\\[0mm]\hline
- \vx_1^-
- & \centering $\infty$
- & \centering $\only<3>\neginfty\only<6,9-10,13-15,18-19>0$
- & \centering $\only<10,14-15,19>0$
- & \centering $\only<15>0$
- & \centering
- & \centering
- & \centering
- &\\[0mm]\hline
- \vx_2^+
- & \centering $\infty$
- & \centering $\only<3,6>\neginfty\only<9-10,13-15,18-19>{41}$
- & \centering $\only<10,14-15>0\only<19>{41}$
- & \centering $\only<15>0$
- & \centering
- & \centering
- & \centering
- &\\[0mm]\hline
- \vx_2^-
- & \centering $\infty$
- & \centering $\only<3,6>\neginfty\only<9-10,13-15,18-19>\infty$
- & \centering $\only<10,14-15,19>0$
- & \centering $\only<15>0$
- & \centering
- & \centering
- & \centering
- &\\[0mm]\hline
- \vx_3^+
- & \centering $\infty$
- & \centering $\only<3,6,9-10>\neginfty\only<13-15,18-19>{41}$
- & \centering $\only<10>\neginfty\only<14-15,19>{41}$
- & \centering $\only<15>0$
- & \centering
- & \centering
- & \centering
- &\\[0mm]\hline
- \vx_3^-
- & \centering $\infty$
- & \centering $\only<3,6,9-10>\neginfty\only<13-15,18-19>0$
- & \centering $\only<10>\neginfty\only<14-15,19>0$
- & \centering $\only<15>0$
- & \centering
- & \centering
- & \centering
- &\\[0mm]\hline
- \end{array}
- $}
-
- \pos{1,1.3}{\uncover<2-4>{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (2,0.5);\end{tikzpicture}}}
- \pos{3.4,1.3}{\uncover<5-16>{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (1.6,0.5);\end{tikzpicture}}}
- \pos{5.3,1.3}{\uncover<17->{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (2.5,0.5);\end{tikzpicture}}}
- %
- \pos{1,1.8}{\uncover<2-4>{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (2,0.5);\end{tikzpicture}}}
- \pos{3.4,1.8}{\uncover<5->{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (1.6,0.5);\end{tikzpicture}}}
- %
- \pos{1,2.3}{\uncover<2-7>{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (2,0.5);\end{tikzpicture}}}
- \pos{3.4,2.3}{\uncover<8->{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (6.0,0.5);\end{tikzpicture}}}
- %
- \pos{1,2.8}{\uncover<2-7>{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (2,0.5);\end{tikzpicture}}}
- \pos{3.4,2.8}{\uncover<8->{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (6,0.5);\end{tikzpicture}}}
- %
- \pos{1,3.3}{\uncover<2-11>{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (2,0.5);\end{tikzpicture}}}
- \pos{3.4,3.3}{\uncover<12->{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (7.5,0.5);\end{tikzpicture}}}
- %
- \pos{1,3.8}{\uncover<2-11>{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (2,0.5);\end{tikzpicture}}}
- \pos{3.4,3.8}{\uncover<12->{\begin{tikzpicture}[fill opacity=0.25, opacity=0.25]\pgfsetstrokecolor{blue}\filldraw[fill=blue] (0,0) rectangle (7.5,0.5);\end{tikzpicture}}}
-
- \only<21,22>{\brighten\brighten}
-
- \only<21>{\pos{1,1}{{\bf\huge
- \hspace*{1.1cm}\scalebox{2}[3]{\Rot{No further}}
-
- \bigskip
- \scalebox{2}[3]{\Rot{Improvement}}
-
- \bigskip
- \hspace*{1.2cm}\scalebox{2}[3]{\Rot{possible!}}
- }}}
- \only<22>{\pos{0.3,1.5}{{\bf\huge
- \bigskip
- \scalebox{2}[3.5]{\Rot{Least Solution}}
-
- \bigskip
- \bigskip
- \hspace*{3.5cm}\scalebox{2}[3.5]{\Rot{FOUND!}}
- }}}
-\end{frame}
-
-\frame{\frametitle{Theorem}
- \begin{itemize}
- \item<2->
- Our \emph{strategy improvement algorithm}
- computes \emph{least solutions}. %of certain fixpoint equation systems over $\mathbb{Z} \cup \{ \neginfty, \infty \}$.
- \bigskip
- \item<3->
- It can be used for performing \emph{precise zone analysis}.
- % i.e., no widening.
- \bigskip
- \item<4->
- The number of \emph{strategy improvement steps} is at most exponential.
- \bigskip
- \item<5->
- Each \emph{strategy improvement step} can be carried out by \emph{ordinary greatest fixpoint iteration}.
- \bigskip
- \item<6->
- The greatest fixpoint iterations can be performed in \emph{strongly polynomial time}
- using a reduction
- to the \emph{minimum cost flow network problem}.
- \end{itemize}
-}
-
-%%%
-
-\outline{3}
-
-%%%
-
-\begin{frame}{Conclusion}
- \begin{itemize}
- \pause\item
- \emph{Strategy iteration} is an interesting alternative to valued-based Approaches.
- \pause\bigskip\item
- Computes \emph{minimal zones} instead of some small \emph{zones}.
- \pause\bigskip\item
- Extensions:
- \begin{itemize}
- \medskip
- \item[$\bullet$]
- \emph{Template-based} analysis:
-
- \emph{Linear}:
- \includegraphics[height=6mm]{figs/region_convex_poly}, i.e., $\vx + 2\vy \leq b_1 \wedge -\vy \leq b_2$
- (ESOP'07)
-
- \emph{Quadratic}:
- \includegraphics[height=6mm]{figs/region_convex}
- \;
- \includegraphics[height=6mm]{figs/region_general}, i.e.,
- $\vx^2 + 2\vx\vy \leq b_1 \wedge \vy^2 \leq b_2$
- (SAS'10)
- \bigskip
- \item[$\bullet$]
- Strategy Iteration + \emph{SMT solving} (ESOP'11)
-
- \smallskip
- \quad From \;
-%
- $\begin{matrix}\text{
- \scalebox{0.3}{
- \begin{tikzpicture}
- \node (n1) [coordinate]{};
- \node (n2) [coordinate,below of = n1,yshift=-10mm]{};
- \node (n3) [coordinate,below of = n2,yshift=-10mm]{};
- \path[-,ultra thick] (n1) edge [bend right] node [left,xshift=-2mm] {\huge $\mathbf{abstr.} (s_{1})$} (n2);
- \path[-,ultra thick] (n1) edge [bend left] node [right,xshift=2mm] {\huge $\mathbf{abstr.} (s_{1}')$} (n2);
- \path[->,ultra thick] (n2) edge [bend right] node [left,xshift=-2mm] {\huge $\mathbf{abstr.} (s_{2})$} (n3);
- \path[->,ultra thick] (n2) edge [bend left] node [right,xshift=2mm] {\huge $\mathbf{abstr.} (s_{2}')$} (n3);
- \end{tikzpicture}
- }}\end{matrix}$
-%
- \; to \;
-%
- $\mathbf{abstr.} \begin{pmatrix}\text{
- \scalebox{0.3}{
- \begin{tikzpicture}
- \node (n1) [coordinate]{};
- \node (n2) [coordinate,below of = n1,yshift=-10mm]{};
- \node (n3) [coordinate,below of = n2,yshift=-10mm]{};
- \path[-,ultra thick] (n1) edge [bend right] node [left,xshift=-2mm] {\huge $s_{1}$} (n2);
- \path[-,ultra thick] (n1) edge [bend left] node [right,xshift=2mm] {\huge $s_{1}'$} (n2);
- \path[->,ultra thick] (n2) edge [bend right] node [left,xshift=-2mm] {\huge $s_{2}$} (n3);
- \path[->,ultra thick] (n2) edge [bend left] node [right,xshift=2mm] {\huge $s_{2}'$} (n3);
- \end{tikzpicture}
- }}\end{pmatrix}$
-%
-
- \medskip\item[$\bullet$]
- \emph{Unbounded Time} Verification
- for \emph{Cyber-Physical Systems}
- through Abstract Interpretation (ATVA'11, APLAS'11, Current Work)
- \end{itemize}
- \end{itemize}
-
- \vspace*{-2mm}
- \begin{center}
- \Large\bf
- \pause Thanks for Your Attention! \pause Questions?
- \end{center}
-\end{frame}
-
-%%%
-
-\begin{frame}[allowframebreaks]{References}
- \bibliographystyle{apalike2}
- \bibliography{bib}
-\end{frame}