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Conditional lexicographic orders in constraint satisfaction problems

Richard J. Wallace, Nic Wilson
2008 Annals of Operations Research  
Rights Abstract The lexicographically-ordered CSP ("lexicographic CSP" or "LO-CSP" for short) combines a simple representation of preferences with the feasibility constraints of ordinary CSPs.  ...  For problems of the first type, any of the algorithms originally devised for ordinary LO-CSPs can also be used when some of the domain orderings are dependent on assignments to "parent" variables.  ...  We are grateful to the editors and referees for their comments and suggestions, which helped improve the exposition of this paper.  ... 
doi:10.1007/s10479-008-0385-3 fatcat:d2vois6fnfd2helkndkb7yjnba

Burrows Wheeler Transform on a Large Scale: Algorithms Implemented in Apache Spark [article]

Ylenia Galluzzo, Raffaele Giancarlo, Mario Randazzo, Simona E. Rombo
2021 arXiv   pre-print
Here we propose algorithms for the computation of Burrows Wheeler transform relying on Big Data technologies, i.e., Apache Spark and Hadoop.  ...  With the rapid growth of Next Generation Sequencing (NGS) technologies, large amounts of "omics" data are daily collected and need to be processed.  ...  Procedure 2 Partial Suffix Arrays Computation 1: procedure CALCULATE PARTIAL SA(p) 2: Calculate l max the maximum distance between two elements in p 3: Generate L the list of S[p[i], l max ] for each i  ... 
arXiv:2107.03341v1 fatcat:cjnjnkpoovfdzpuqcef63jceq4

A Big Data Approach for Sequences Indexing on the Cloud via Burrows Wheeler Transform [article]

Mario Randazzo, Simona E. Rombo
2020 arXiv   pre-print
Here we propose an algorithm for the computation of Burrows Wheeler transform relying on Big Data technologies, i.e., Apache Spark and Hadoop.  ...  Indexing sequence data is important in the context of Precision Medicine, where large amounts of "omics" data have to be daily collected and analyzed in order to categorize patients and identify the most  ...  ACKNOWLEDGEMENTS Part of the research presented here has been funded by the MIUR-PRIN research project "Multicriteria Data Structures and Algorithms: from compressed to learned indexes, and beyond", grant  ... 
arXiv:2007.10095v1 fatcat:vqd7mydjgvhspnfi4csvn572aq

Efficient computation paths for the systematic analysis of sensitivities

Paolo Greppi, Elisabetta Arato
2013 Computer Physics Communications  
Some simple, easy-to-visualize examples are presented, followed by performance results for the quasi-spiral algorithm and the practical application of the different paths in a process simulation tool.  ...  Scanning the domain in the obvious order is sub-optimal in terms of total iterations and is likely to cause many solution failures.  ...  The lexicographical ordering is the same as the zigzag path mentioned above, and provides its generalization for more than two dimensions.  ... 
doi:10.1016/j.cpc.2012.08.018 fatcat:n5hihw3qgvhm3c4nxurwdpn4aq

Ranked Enumeration of Conjunctive Query Results [article]

Shaleen Deep, Paraschos Koutris
2021 arXiv   pre-print
We introduce the notion of decomposable and compatible ranking functions in conjunction with query decomposition, a property that allows for partial aggregation of tuple scores in order to efficiently  ...  The task is to design data structures and algorithms that allow for efficient enumeration after a preprocessing phase.  ...  Here, the lexicographic order is chosen by the algorithm and not the user.  ... 
arXiv:1902.02698v3 fatcat:3kl72emlvrbazjbelc6sp7zn34

MISTRAL: Processing Relational Queries using a Multidimensional Access Technique [chapter]

Volker Markl
2000 Ausgezeichnete Informatikdissertationen 1999  
For this thesis, my colleagues also did a lot of proofreading, which certainly improved the quality of the work. Wohner. Many thanks also to Prof.  ...  Last but not least I thank the Deutsche Bahn (German Rail), since the solution to many algorithmic problems (like the range query algorithm, multidimensional hierarchical clustering) and many new ideas  ...  The same holds for Algorithm 5-2 to calculate the Cartesian coordinates of a tuple from its address.  ... 
doi:10.1007/978-3-322-84823-9_15 dblp:conf/gi/Markl99 fatcat:mg4ldvzrofh4voexja7nn37p4m

Data-Driven Loop Bound Learning for Termination Analysis

Rongchen Xu, Jianhui Chen, Fei He0001
2022 International Conference on Software Engineering  
We present efficient data-driven algorithms for inferring various kinds of loop bounds, including simple loop bounds, conjunctive loop bounds, and lexicographic loop bounds.  ...  Termination is a fundamental liveness property for program verification. A loop bound is an upper bound of the number of loop iterations for a given program.  ...  Without loss of generality, suppose branch B1 is bound to idc 1 and branch B2 is bound to idc 2 . For each trace in H ρ , we calculate the values of idc backward along that trace.  ... 
doi:10.1145/3510003.3510220 dblp:conf/icse/XuCH22 fatcat:6kwuh7e2ijbenmjyb7blp24sha


Włodzimierz Bielecki, Piotr Skotnicki
2017 Computer Science  
The paper presents an approach for code generation that allows for the free schedule for tiles of arbitrarily nested affine loops at run-time.  ...  The scope of the applicability of the introduced algorithms is limited to tiled loop nests whose inter-tile dependence graphs are cycle-free. The approach is based on the polyhedral model.  ...  Techniques aimed at breaking cycles in the original inter-tile dependence graph and then calculating the free schedule at run-time will be addressed in our future publications.  ... 
doi:10.7494/csci.2017.18.2.195 fatcat:z62idoea65h45cn2oxwh7m3f4i

A Survey on Mining User-Aware Rare Sequential Pattern

2017 International Journal of Science and Research (IJSR)  
To address the problem of finding frequent and rare itemsets from the data streams, we propose another algorithm called New_SPAM.  ...  New_SPAM Algorithm is the combination of both Per_SPAM and Min_SPAM algorithm.  ...  Assume that there is a lexicographical orderingof the items I in the database. If item i occurs before item j in the ordering, then denote this by i ≤ Ij.  ... 
doi:10.21275/art20164632 fatcat:35qtyobxmvbk5dcdvdrftyjcu4

Expressiveness and complexity of order dependencies

Jaroslaw Szlichta, Parke Godfrey, Jarek Gryz, Calisto Zuzarte
2013 Proceedings of the VLDB Endowment  
We study order dependencies (ODs)-and unidirectional order dependencies (UODs), a proper sub-class of ODs-which describe the relationships among lexicographical orderings of sets of tuples.  ...  We consider lexicographical ordering, as by the order-by operator in SQL, because this is the notion of order used in SQL and within query optimization.  ...  The complexity of the inference problem for (lexicographical) OD has heretofore not been known. We address this in this work.  ... 
doi:10.14778/2556549.2556568 fatcat:h5mjqhrrfvbj5nzpclr4vj2y7i

Effective and complete discovery of order dependencies via set-based axiomatization

Jaroslaw Szlichta, Parke Godfrey, Lukasz Golab, Mehdi Kargar, Divesh Srivastava
2017 Proceedings of the VLDB Endowment  
Our algorithm has exponential worst-case time complexity, O(2 |R| ), in the number of attributes |R| and linear complexity in the number of tuples.  ...  Hence, proposals for automatic discovery have been made for some classes of ICs, such as functional dependencies (FDs), and recently, order dependencies (ODs).  ...  For all single attributes A ∈ R at level l = 2, we calculate sorted partitions τ A . A sorted partition τ A is a list of equivalence classes according to the ordering imposed on the tuples by A.  ... 
doi:10.14778/3067421.3067422 fatcat:s5dwqctbtrdzxh5xkco4io2n3e


2008 International Journal of Foundations of Computer Science  
This method avoids a rejection phase, that would be needed if a generation algorithm for a larger class of objects that contains the MADFAs were used.  ...  Using this normal form, we present a method for the exact generation of MADFAs.  ...  We thank also the anonymous referees for their valuable comments.  ... 
doi:10.1142/s0129054108005930 fatcat:qzi4mn5efnfl5g62avueuczhmu

A Theoretical and Experimental Study on the Construction of Suffix Arrays in External Memory

Crauser, Ferragina
2002 Algorithmica  
In this paper we analyze, both theoretically and experimentally, the I/O-complexity and the working space of six algorithms for constructing large su x arrays.  ...  Three of them are the state-of-the-art, the other three algorithms are our new proposals.  ...  Results for the Doubl+Disc+Radix algorithm. This algorithm is not as fast as we conjectured in Section 2.2.2, even for the tuple ordering of Step 2.  ... 
doi:10.1007/s00453-001-0051-5 fatcat:ahux4xnt25fzfhn7htyziq3nxq

Tiling Nussinov's RNA folding loop nest with a space-time approach

Marek Palkowski, Wlodzimierz Bielecki
2019 BMC Bioinformatics  
Results: We suggest a space-time tiling approach and apply it to generate parallel cache effective tiled code for RNA folding using Nussinov's algorithm.  ...  Generated parallel tiled code is scalable regarding to the number of parallel threadsincreasing the number of threads reduces code execution time.  ...  Availability of data and materials At the address, all source codes used for carrying out experiments can be found as well as a program allowing us to run each parallel  ... 
doi:10.1186/s12859-019-2785-6 fatcat:lu47i4i355abpmfxyoaojasjvi

Optimal Algorithms for Ranked Enumeration of Answers to Full Conjunctive Queries [article]

Nikolaos Tziavelis, Deepak Ajwani, Wolfgang Gatterbauer, Mirek Riedewald, Xiaofeng Yang
2020 arXiv   pre-print
We study ranked enumeration of join-query results according to very general orders defined by selective dioids.  ...  Our technique is not only faster for returning the first few results, but on some inputs beats the batch algorithm even when all results are produced.  ...  Ngo for reading drafts of this paper and providing valuable feedback.  ... 
arXiv:1911.05582v3 fatcat:6o76icz54fhhtcduouv64udvvu
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