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Incorporated Vitor's minimal changes.

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kostis 2007-06-06 21:01:46 +00:00
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21
docs/index/iclp07.tex
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@ -133,7 +133,7 @@ features that drastically depart from WAM's basic characteristics.
% %
For example, first argument indexing is sufficient for many Prolog For example, first argument indexing is sufficient for many Prolog
applications. However, it is clearly sub-optimal for applications applications. However, it is clearly sub-optimal for applications
accessing large databases; for a long time now, the database community accessing large data sets; for a long time now, the database community
has recognized that good indexing is the basis for fast query has recognized that good indexing is the basis for fast query
processing. processing.
@ -293,12 +293,12 @@ removes it.
The WAM has additional indexing instructions (\instr{try\_me\_else} The WAM has additional indexing instructions (\instr{try\_me\_else}
and friends) that allow indexing to be interspersed with the code of and friends) that allow indexing to be interspersed with the code of
clauses. For simplicity of presentation we will not consider them clauses. For simplicity of presentation we will not consider them
here. This is not a problem since the above scheme handles all cases. here. This is not a problem since the above scheme handles all programs.
Also, we will feel free to do some minor modifications and Also, we will feel free to do some minor modifications and
optimizations when this simplifies things. optimizations when this simplifies things.
We present an example. Consider the Prolog code shown in We present an example. Consider the Prolog code shown in
Fig.~\ref{fig:carc:facts}. It is a fragment of the well-known machine Fig.~\ref{fig:carc:facts}. It is a fragment of the machine
learning dataset \textit{Carcinogenesis}~\cite{Carcinogenesis@ILP-97}. learning dataset \textit{Carcinogenesis}~\cite{Carcinogenesis@ILP-97}.
The five clauses get compiled to the WAM code shown in The five clauses get compiled to the WAM code shown in
Fig.~\ref{fig:carc:clauses}. The first argument indexing indexing code Fig.~\ref{fig:carc:clauses}. The first argument indexing indexing code
@ -807,7 +807,7 @@ to a \switchSTAR WAM instruction.
\end{itemize} \end{itemize}
\end{itemize} \end{itemize}
\item[2.2.4] transform the \jitiSTAR $r, l, k$ instruction to \item[2.2.4] transform the \jitiSTAR $r, l, k$ instruction to
a \switchSTAR $r, l, \&{\cal T}$ instruction; and a \switchSTAR $r, l, {\cal T}$ instruction; and
\item[2.2.5] continue execution with this instruction. \item[2.2.5] continue execution with this instruction.
\end{itemize} \end{itemize}
\end{enumerate} \end{enumerate}
@ -821,7 +821,7 @@ query execution. First, note that each demanded index table will be
constructed at most once. Also, a \jitiSTAR instruction will be constructed at most once. Also, a \jitiSTAR instruction will be
encountered only in cases where execution would examine all clauses in encountered only in cases where execution would examine all clauses in
the \TryRetryTrust chain.\footnote{This statement is possibly not the \TryRetryTrust chain.\footnote{This statement is possibly not
valid the presence of Prolog cuts.} The construction visits these valid in the presence of Prolog cuts.} The construction visits these
clauses \emph{once} and then creates the index table in time linear in clauses \emph{once} and then creates the index table in time linear in
the number of clauses as one pass over the list of $\langle c, L the number of clauses as one pass over the list of $\langle c, L
\rangle$ pairs suffices. After index construction, execution will \rangle$ pairs suffices. After index construction, execution will
@ -1003,7 +1003,7 @@ construction. We therefore wanted to measure this overhead.
% %
As both systems support tabling, we decided to use tabling benchmarks As both systems support tabling, we decided to use tabling benchmarks
because they are small and easy to understand, and because they are a because they are small and easy to understand, and because they are a
worst case for JITI in the following sense: tabling avoids generating bad case for JITI in the following sense: tabling avoids generating
repetitive queries and the benchmarks operate over extensional repetitive queries and the benchmarks operate over extensional
database (EDB) predicates of size approximately equal the size of the database (EDB) predicates of size approximately equal the size of the
program. We used \compress, a tabled program that solves a puzzle from program. We used \compress, a tabled program that solves a puzzle from
@ -1298,6 +1298,15 @@ performance can be achieved in the context of one solution
computations, or in the context of tabling where order of clauses and computations, or in the context of tabling where order of clauses and
solutions does not matter and repeated solutions are discarded. solutions does not matter and repeated solutions are discarded.
\paragraph{Acknowledgments}
This work is dedicated to the memory of our friend and colleague
Ricardo Lopes. We miss you! V\'{\i}tor Santos Costa was partially
supported by CNPq and would like to acknowledge support received while
visiting at UW-Madison and the support of the YAP user community.
This work has been partially supported by MYDDAS (POSC/EIA/59154/2004)
and by funds granted to LIACC through the Programa de Financiamento
Plurianual, Fundação para a Ciência e Tecnologia and Programa POSC.
%============================================================================== %==============================================================================
\bibliographystyle{splncs} \bibliographystyle{splncs}