Pushdown Automaton

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Zengo Furukawa - One of the best experts on this subject based on the ideXlab platform.

Jan Janousek - One of the best experts on this subject based on the ideXlab platform.

  • SLATE - Target Code Selection by Tilling AST with the Use of Tree Pattern Pushdown Automaton.
    2014
    Co-Authors: Jan Janousek, Jaroslav Málek
    Abstract:

    A new and simple method for target code selection by tilling an abstract syntax tree is presented. As it is usual, tree patterns corresponding to target machine instructions are matched in the abstract syntax tree. Matching tree patterns is performed with the use of tree pattern Pushdown Automaton, which accepts all tree patterns matching the abstract syntax tree in the linear postfix bar notation and represents a full index of the abstract syntax tree for tree patterns. The use of the index allows to match patterns quickly, in time depending on the size of patterns and not depending on the size of the tree. The selection of a particular target instruction corresponds to a modification of the abstract syntax tree and also a corresponding incremental modification of the index is performed. A reference to a fully functional prototype is provided.

  • target code selection by tilling ast with the use of tree pattern Pushdown Automaton
    Symposium on Languages Applications and Technologies, 2014
    Co-Authors: Jan Janousek, Jaroslav Málek
    Abstract:

    A new and simple method for target code selection by tilling an abstract syntax tree is presented. As it is usual, tree patterns corresponding to target machine instructions are matched in the abstract syntax tree. Matching tree patterns is performed with the use of tree pattern Pushdown Automaton, which accepts all tree patterns matching the abstract syntax tree in the linear postfix bar notation and represents a full index of the abstract syntax tree for tree patterns. The use of the index allows to match patterns quickly, in time depending on the size of patterns and not depending on the size of the tree. The selection of a particular target instruction corresponds to a modification of the abstract syntax tree and also a corresponding incremental modification of the index is performed. A reference to a fully functional prototype is provided.

  • Tree compression Pushdown Automaton
    Kybernetika, 2012
    Co-Authors: Jan Janousek, Borivoj Melichar, Martin Poliak
    Abstract:

    A new kind of a deterministic Pushdown Automaton, called a Tree Compression Automaton, is presented. The tree compression Automaton represents a complete compressed index of a set of trees for subtrees and accepts all subtrees of given trees. The algorithm for constructing our Pushdown Automaton is incremental. For a single tree with $n$ nodes, the Automaton has at most $n+1$ states, its transition function cardinality is at most $4n$ and there are $2n+1$ Pushdown store symbols. If hashing is used for storing Automaton's transitions, thus removing a factor of $log n$, the construction of the Automaton takes linear time and space with respect to the length $n$ of the input tree(s). Our Pushdown Automaton construction can also be used for finding all subtree repeats without augmenting the overall complexity.

  • Indexing ordered trees for (nonlinear) tree pattern matching by Pushdown automata
    Computer Science and Information Systems, 2012
    Co-Authors: Jan Trávníček, Jan Janousek, Borivoj Melichar
    Abstract:

    Trees are one of the fundamental data structures used in Computer Science. We present a new kind of acyclic Pushdown automata, the tree pattern Pushdown Automaton and the nonlinear tree pattern Pushdown Automaton, constructed for an ordered tree. These automata accept all tree patterns and nonlinear tree patterns, respectively, which match the tree and represent a full index of the tree for such patterns. Given a tree with n nodes, the numbers of these distinct tree patterns and nonlinear tree patterns can be at most 2n−1 +n and at most (2+v)n−1+2, respectively, where v is the maximal number of nonlinear variables allowed in nonlinear tree patterns. The total sizes of nondeterministic versions of the two Pushdown automata are O(n) and O(n2), respectively. We discuss the time complexities and show timings of our implementations using the bit-parallelism technique. The timings show that for a given tree the running time is linear to the size of the input pattern.

  • Indexing trees by Pushdown automata for nonlinear tree pattern matching
    2011
    Co-Authors: Jan Trávníček, Jan Janousek, Borivoj Melichar
    Abstract:

    A new kind of an acyclic Pushdown Automaton for an ordered tree is presented. The nonlinear tree pattern Pushdown Automaton represents a complete index of the tree for nonlinear tree patterns and accepts all nonlinear tree patterns which match the tree. Given a tree with n nodes, the number of such nonlinear tree patterns is O((2+v)n), where v is the number of variables in the patterns. We discuss time and space complexities of the nondeterministic nonlinear tree pattern Pushdown Automaton and a way of its implementation. The presented Pushdown Automaton is input-driven and therefore can be determinised.

Jean-marc Talbot - One of the best experts on this subject based on the ideXlab platform.

  • Trimming visibly Pushdown automata
    Theoretical Computer Science, 2015
    Co-Authors: Mathieu Caralp, Pierre-alain Reynier, Jean-marc Talbot
    Abstract:

    We study the problem of trimming visibly Pushdown automata (VPA). We first describe a polynomial time procedure which, given a visibly Pushdown Automaton that accepts only well-nested words, returns an equivalent visibly Pushdown Automaton that is trimmed. We then show how this procedure can be lifted to the setting of arbitrary VPA. Furthermore, we present a way of building, given a VPA, an equivalent VPA which is both deterministic and trimmed. Last, our trimming procedures can be applied to weighted VPA.

  • CIAA - Trimming visibly Pushdown automata
    Implementation and Application of Automata, 2013
    Co-Authors: Mathieu Caralp, Pierre-alain Reynier, Jean-marc Talbot
    Abstract:

    We study the problem of trimming visibly Pushdown automata (VPA). We first describe a polynomial time procedure which, given a visibly Pushdown Automaton that accepts only well-nested words, returns an equivalent visibly Pushdown Automaton that is trimmed. We then show how this procedure can be lifted to the setting of arbitrary VPA. Furthermore, we present a way of building, given a VPA, an equivalent VPA which is both deterministic and trimmed.

  • A polynomial procedure for trimming visibly Pushdown automata
    2011
    Co-Authors: Mathieu Caralp, Pierre-alain Reynier, Jean-marc Talbot
    Abstract:

    We describe a polynomial procedure which, given a visibly Pushdown Automaton that accepts only well-nested words, returns an equivalent visibly Pushdown Automaton that is trimmed. We also show that this procedure can be applied to weighted visibly Pushdown automata such as visibly Pushdown transducers.

Tomohiko Takagi - One of the best experts on this subject based on the ideXlab platform.

Didier Caucal - One of the best experts on this subject based on the ideXlab platform.

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