Improving Program Performance via Auto-Vectorization of Loops with Conditional Statements with GCC Compiler Setting

2013 ◽  
Vol 433-435 ◽  
pp. 1410-1414
Author(s):  
Qi Shen Zhu
Keyword(s):  
Search Space ◽  
Compiler Optimizations ◽  
Program Performance ◽  
Performance Improvements ◽  
Iterative Compilation ◽  
Conditional Statements ◽  
Speed Up ◽  
Performance Ability ◽  
Number Of Passes ◽  
Selection Of

The GCC is an auto-vectorization compiler across iterations of loops to parallelism data. Turning GCC compiler optimizations flags for auto-vectorization is a way to improve the performance ability, which is a popular approach to speed up program performance. However, there are many options in GCC compiler and selecting the best combination of these options to improve program performance through vectorization is non-trivial ( as the search space is very large ).In this work we focus on the selection of compiler transformations to auto-vectorize loops with conditional statements. The selection of compiler transformations is based on the correlation between program features, speed-up, and the analysis of the code generated and a small number of passes of iterative compilation. Our preliminary experimental results show that proposed technique attains performance improvements the best ~ 6x using loops in the TSVC benchmark suite on the state-of-the-art Intel Core i3 processor.

Selection of Part Orientation for Multi-Axis Hybrid Manufacturing Process

2009 ◽  
Author(s):  
Jianzhong Ruan ◽  
Jun Zhang ◽  
Frank Liou
Keyword(s):  
Manufacturing Process ◽  
Search Space ◽  
Deposition Process ◽  
Hybrid Manufacturing ◽  
Optimal Orientation ◽  
Multi Stage ◽  
Build Time ◽  
Speed Up ◽  
Computation Algorithm ◽  
Selection Of

In regular 3 axis layered manufacturing processes, the build direction is fixed throughout the process. Multi-axis laser (more than 3-axis motion) deposition process, the orientation of the part can affect the non-support buildability in the multi-axis hybrid manufacturing process. However, each orientation that satisfies the buildability and other constraints may not be unique. In this case, the final optimal orientation is determined based on build time. The build time computation algorithm for multi-axis hybrid system is presented in this paper. To speed up the exhaustive search for the optimal orientation, a multi-stage algorithm is developed to reduce the search space.

An Interactive Visualization of Genetic Algorithm on 2-D Graph

2012 ◽  
Vol 4 (1) ◽  
pp. 34-54 ◽  
Author(s):  
Humera Farooq ◽  
Nordin Zakaria ◽  
Muhammad Tariq Siddique
Keyword(s):  
Genetic Algorithm ◽  
Growth Process ◽  
Search Space ◽  
Human Intervention ◽  
Branching Structures ◽  
Multidimensional Search ◽  
L System ◽  
User Fatigue ◽  
Search Data ◽  
Selection Of

The visualization of search space makes it easy to understand the behavior of the Genetic Algorithm (GA). The authors propose a novel way for representation of multidimensional search space of the GA using 2-D graph. This is carried out based on the gene values of the current generation, and human intervention is only required after several generations. The main contribution of this research is to propose an approach to visualize the GA search data and improve the searching process of the GA with human’s intention in different generations. Besides the selection of best individual or parents for the next generation, interference of human is required to propose a new individual in the search space. Active human intervention leads to a faster searching, resulting in less user fatigue. The experiments were carried out by evolving the parameters to derive the rules for a Parametric L-System. These rules are then used to model the growth process of branching structures in 3-D space. The experiments were conducted to evaluate the ability of the proposed approach to converge to optimized solution as compared to the Simple Genetic Algorithm (SGA).

An expectation-based account of subject islands and parasitism

2012 ◽  
Vol 49 (2) ◽  
pp. 285-327 ◽  
Author(s):  
RUI P. CHAVES
Keyword(s):  
Full Range ◽  
Search Space ◽  
Functional Explanation ◽  
Parasitic Extraction ◽  
Speed Up

Subject phrases impose particularly strong constraints on extraction. Most research assumes a syntactic account (e.g. Kayne 1983, Chomsky 1986, Rizzi 1990, Lasnik & Saito 1992, Takahashi 1994, Uriagereka 1999), but there are also pragmatic accounts (Erteschik-Shir & Lappin 1979; Van Valin 1986, 1995; Erteschik-Shir 2006, 2007) as well as performance-based approaches (Kluender 2004). In this work I argue that none of these accounts captures the full range of empirical facts, and show that subject and adjunct phrases (phrasal or clausal, finite or otherwise) are by no means impermeable to non-parasitic extraction of nominal, prepositional and adverbial phrases. The present empirical reassessment indicates that the phenomena involving subject and adjunct islands defies the formulation of a general grammatical account. Drawing from insights by Engdahl (1983) and Kluender (2004), I argue that subject island effects have a functional explanation. Independently motivated pragmatic and processing limitations cause subject-internal gaps to be heavily dispreferred, and therefore, extremely infrequent. In turn, this has led to heuristic parsing expectations that preempt subject-internal gaps and therefore speed up processing by pruning the search space of filler–gap dependencies. Such expectations cause processing problems when violated, unless they are dampened by prosodic and pragmatic cues that boost the construction of the correct parse. This account predicts subject islands and their (non-)parasitic exceptions.

Computer Control by Gaze

2012 ◽  
pp. 78-102 ◽  
Author(s):  
Henrik Skovsgaard ◽  
Kari-Jouko Räihä ◽  
Martin Tall
Keyword(s):  
Eye Gaze ◽  
Computer Control ◽  
Target Selection ◽  
Specific Area ◽  
Head Movements ◽  
Interaction Techniques ◽  
Information Spaces ◽  
Speed Up ◽  
Small Targets ◽  
Selection Of

This chapter provides an overview of gaze-based interaction techniques. We will first explore specific techniques intended to make target selection easier and to avoid the Midas touch problem. We will then take a look at techniques that do not require the use of special widgets in the interface but instead manipulate the rendering on the basis of eye gaze to facilitate the selection of small targets. Dwell-based interaction makes use of fixations; recent research has looked into the other option, using saccades as the basis for eye gestures. We will also discuss examples of how eye gaze has been used with other input modalities (blinks and winks, keyboard and mouse, facial gestures, head movements, and speech) to speed up interaction. Finally, we will discuss examples of interaction techniques in the context of a specific area of application: navigating information spaces.

Chapter 13. Symmetry and Satisfiability

2021 ◽  
Author(s):  
Karem A. Sakallah
Keyword(s):  
Group Theory ◽  
Normal Form ◽  
Boolean Functions ◽  
Search Algorithm ◽  
Conjunctive Normal Form ◽  
Search Space ◽  
Decision Problems ◽  
Mathematical Language ◽  
Sat Solvers ◽  
Speed Up

Symmetry is at once a familiar concept (we recognize it when we see it!) and a profoundly deep mathematical subject. At its most basic, a symmetry is some transformation of an object that leaves the object (or some aspect of the object) unchanged. For example, a square can be transformed in eight different ways that leave it looking exactly the same: the identity “do-nothing” transformation, 3 rotations, and 4 mirror images (or reflections). In the context of decision problems, the presence of symmetries in a problem’s search space can frustrate the hunt for a solution by forcing a search algorithm to fruitlessly explore symmetric subspaces that do not contain solutions. Recognizing that such symmetries exist, we can direct a search algorithm to look for solutions only in non-symmetric parts of the search space. In many cases, this can lead to significant pruning of the search space and yield solutions to problems which are otherwise intractable. This chapter explores the symmetries of Boolean functions, particularly the symmetries of their conjunctive normal form (CNF) representations. Specifically, it examines what those symmetries are, how to model them using the mathematical language of group theory, how to derive them from a CNF formula, and how to utilize them to speed up CNF SAT solvers.

On the Similarity Search With Hamming Space Sketches

2021 ◽  
pp. 97-127
Author(s):  
Vladimir Mic ◽  
Pavel Zezula
Keyword(s):  
Computational Complexity ◽  
Metric Space ◽  
Similarity Search ◽  
Space Model ◽  
Similarity Query ◽  
Speed Up ◽  
Hamming Space ◽  
Definition Of ◽  
Metric Function ◽  
Selection Of

This chapter focuses on data searching, which is nowadays mostly based on similarity. The similarity search is challenging due to its computational complexity, and also the fact that similarity is subjective and context dependent. The authors assume the metric space model of similarity, defined by the domain of objects and the metric function that measures the dissimilarity of object pairs. The volume of contemporary data is large, and the time efficiency of similarity query executions is essential. This chapter investigates transformations of metric space to Hamming space to decrease the memory and computational complexity of the search. Various challenges of the similarity search with sketches in the Hamming space are addressed, including the definition of sketching transformation and efficient search algorithms that exploit sketches to speed-up searching. The indexing of Hamming space and a heuristic to facilitate the selection of a suitable sketching technique for any given application are also considered.

scholarly journals File Size and the Cost of Processing MARC Records

1971 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
John P. Kennedy
Keyword(s):  
Title Page ◽  
Significant Determinant ◽  
Georgia Tech ◽  
File Size ◽  
The Cost ◽  
Number Of Passes ◽  
Selection Of

<div class="page" title="Page 1"><div class="section"><div class="layoutArea"><div class="column"><p><span>Many systems being developed for utilizing MARC records in acquisitions and cataloging operations depend on the selection of records from a cumulative tape </span><span>file</span><span>. </span><span>Analysis of cost </span><span>data </span><span>accumulated during two years' experi</span><span>e</span><span>nce in using MARC records for the production of catalog cards at the Georgia Tech Library indicates that the ratio of titles selected to titles read from the </span><span>c</span><span>umulative </span><span>file </span><span>is the most significant determinant of cost. This implies that the number of passes of the </span><span>file </span><span>must be minimized and </span><span>an </span><span>effective formula for limiting the growth of the </span><span>file </span><span>must be developed in the design of an </span><span>e</span><span>conomical system. </span></p></div></div></div></div>

Automated Cryptanalysis of Classical Ciphers

2011 ◽  
pp. 186-191
Author(s):  
Otokar Grošek ◽  
Pavol Zajac
Keyword(s):  
Artificial Intelligence ◽  
Natural Language ◽  
Language Processing ◽  
Text Processing ◽  
Search Space ◽  
Text Recognition ◽  
Brute Force Search ◽  
Key Space ◽  
Optimization Heuristics ◽  
Speed Up

Classical ciphers are used to encrypt plaintext messages written in a natural language in such a way that they are readable for sender or intended recipient only. Many classical ciphers can be broken by brute-force search through the key-space. Methods of artificial intelligence, such as optimization heuristics, can be used to narrow the search space, to speed-up text processing and text recognition in the cryptanalytic process. Here we present a broad overview of different AI techniques usable in cryptanalysis of classical ciphers. Specific methods to effectively recognize the correctly decrypted text among many possible decrypts are discussed in the next part Automated cryptanalysis – Language processing.

scholarly journals Mobile robot path planning using an improved ant colony optimization

2018 ◽  
Vol 15 (3) ◽  
pp. 172988141877467 ◽  
Author(s):  
Khaled Akka ◽  
Farid Khaber
Keyword(s):  
Path Planning ◽  
Mobile Robot ◽  
Ant Colony Algorithm ◽  
Search Space ◽  
Step Length ◽  
Ant Colony ◽  
Dynamic Adjustment ◽  
Feedback Information ◽  
Intelligent Optimization Algorithm ◽  
Selection Of

Ant colony algorithm is an intelligent optimization algorithm that is widely used in path planning for mobile robot due to its advantages, such as good feedback information, strong robustness and better distributed computing. However, it has some problems such as the slow convergence and the prematurity. This article introduces an improved ant colony algorithm that uses a stimulating probability to help the ant in its selection of the next grid and employs new heuristic information based on the principle of unlimited step length to expand the vision field and to increase the visibility accuracy; and also the improved algorithm adopts new pheromone updating rule and dynamic adjustment of the evaporation rate to accelerate the convergence speed and to enlarge the search space. Simulation results prove that the proposed algorithm overcomes the shortcomings of the conventional algorithms.

Improving Matsui’s Search Algorithm For The Best Differential/Linear Trails And Its Applications For DES, DESL And GIFT

2020 ◽  
Author(s):  
Fulei Ji ◽  
Wentao Zhang ◽  
Tianyou Ding
Keyword(s):  
Search Algorithm ◽  
Search Space ◽  
Search Methods ◽  
New Methods ◽  
Linear Layer ◽  
Speed Up ◽  
Automatic Search ◽  
The Cost ◽  
First Time ◽  
Improved Algorithm

Abstract Automatic search methods have been widely used for cryptanalysis of block ciphers, especially for the most classic cryptanalysis methods—differential and linear cryptanalysis. However, the automatic search methods, no matter based on MILP, SMT/SAT or CP techniques, can be inefficient when the search space is too large. In this paper, we propose three new methods to improve Matsui’s branch-and-bound search algorithm, which is known as the first generic algorithm for finding the best differential and linear trails. The three methods, named reconstructing DDT and LAT according to weight, executing linear layer operations in minimal cost and merging two 4-bit S-boxes into one 8-bit S-box, respectively, can efficiently speed up the search process by reducing the search space as much as possible and reducing the cost of executing linear layer operations. We apply our improved algorithm to DESL and GIFT, which are still the hard instances for the automatic search methods. As a result, we find the best differential trails for DESL (up to 14-round) and GIFT-128 (up to 19-round). The best linear trails for DESL (up to 16-round), GIFT-128 (up to 10-round) and GIFT-64 (up to 15-round) are also found. To the best of our knowledge, these security bounds for DESL and GIFT under single-key scenario are given for the first time. Meanwhile, it is the longest exploitable (differential or linear) trails for DESL and GIFT. Furthermore, benefiting from the efficiency of the improved algorithm, we do experiments to demonstrate that the clustering effect of differential trails for 13-round DES and DESL are both weak.

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