Tight Polynomial Bounds for Loop Programs in Polynomial Space

2021 ◽  
Vol Volume 17, Issue 4 ◽  
Author(s):  
A. M. Ben-Amram ◽  
G. W. Hamilton
Keyword(s):  
Program Analysis ◽  
Decision Procedure ◽  
Polynomial Space ◽  
Analysis Problem ◽  
Analysis Algorithm ◽  
Asymptotic Bounds ◽  
Bounded Variables ◽  
New Space ◽  
Polynomial Bounds ◽  
Program Point

We consider the following problem: given a program, find tight asymptotic bounds on the values of some variables at the end of the computation (or at any given program point) in terms of its input values. We focus on the case of polynomially-bounded variables, and on a weak programming language for which we have recently shown that tight bounds for polynomially-bounded variables are computable. These bounds are sets of multivariate polynomials. While their computability has been settled, the complexity of this program-analysis problem remained open. In this paper, we show the problem to be PSPACE-complete. The main contribution is a new, space-efficient analysis algorithm. This algorithm is obtained in a few steps. First, we develop an algorithm for univariate bounds, a sub-problem which is already PSPACE-hard. Then, a decision procedure for multivariate bounds is achieved by reducing this problem to the univariate case; this reduction is orthogonal to the solution of the univariate problem and uses observations on the geometry of a set of vectors that represent multivariate bounds. Finally, we transform the univariate-bound algorithm to produce multivariate bounds.

Layered Region Based Flow-Sensitive Demand-Driven Alias Analysis

2014 ◽  
Vol 577 ◽  
pp. 917-920
Author(s):  
Long Pang ◽  
Xiao Hong Su ◽  
Pei Jun Ma ◽  
Ling Ling Zhao
Keyword(s):  
Program Analysis ◽  
Control Flow ◽  
Alias Analysis ◽  
Reachability Problem ◽  
Analysis Algorithm ◽  
Context Free Language ◽  
Context Free ◽  
Free Language ◽  
Demand Driven Analysis

The pointer alias is indispensable for program analysis. Comparing to point-to set, it’s more efficient to formulate the alias as the context free language (CFL) reachability problem. However, the precision is limited to flow-insensitivity. To solve this problem, we propose a flow sensitive, demand-driven analysis algorithm for answering may-alias queries. First the partial single static assignment is used to discriminate the address-taken pointers. Then the order of control flow is encoded in the level linearization code to ease comparison. Finally, the query of alias in demand driven is converted into the search of CFL reachability with feasible flows. The experiments demonstrate the effectiveness of the proposed approach.

scholarly journals Decidable Inequalities over Infinite Trees

10.29007/s21n ◽  
2018 ◽  
Author(s):  
Sabine Bauer ◽  
Steffen Jost ◽  
Martin Hofmann
Keyword(s):  
Entire Range ◽  
Decision Procedure ◽  
Object Oriented ◽  
Rational Numbers ◽  
Resource Analysis ◽  
Analysis Problem ◽  
Inference Mechanism ◽  
Combinatorics Of Words ◽  
Infinite Trees ◽  
The Given

Linear tree constraints are given by pointwise linear inequalities between infinite trees labeled with nonnegative rational numbers. Satisfiablity of such constraints is at least as hard as solving the Skolem-Mahler-Lech Problem. We provide an interesting subcase, for which we prove that satisfiablity is decidable. Our decision procedure is based on intricate arguments using automata and combinatorics of words.Our subcase allows to construct an inference mechanism for resource bounds of object oriented Java-like programs: actual resource bounds can be read off from solutions of tree constraints. So far, only the case of degenerated tree constraints (i.e. lists) was known to be decidable which, however, is insufficient to generally solve the given resource analysis problem. The present paper therefore provides a generalisation to trees of higher degree in order to cover the entire range of constraints encountered by resource analysis.

scholarly journals The semantics of future and an application

1999 ◽  
Vol 9 (1) ◽  
pp. 1-31 ◽  
Author(s):  
C. FLANAGAN ◽  
M. FELLEISEN
Keyword(s):  
Optimization Algorithm ◽  
Program Analysis ◽  
Operational Semantics ◽  
Functional Language ◽  
Design Issues ◽  
Simple Method ◽  
Analysis Algorithm ◽  
The Third ◽  
Parallel Tasks

The future annotation of MultiLisp provides a simple method for taming the implicit parallelism of functional programs. Prior research on future has concentrated on implementation and design issues, and has largely ignored the development of a semantic characterization of future. This paper considers an idealized functional language with futures and presents a series of operational semantics with increasing degrees of intensionality. The first semantics defines future to be a semantically transparent annotation. The second semantics interprets a future expression as a potentially parallel task. The third semantics explicates the coordination of parallel tasks by introducing placeholder objects and touch operations.We use the last semantics to derive a program analysis algorithm and an optimization algorithm that removes provably redundant touch operations. Experiments with the Gambit compiler indicate that this optimization significantly reduces the overhead imposed by touch operations.

Seti Space Missions

1997 ◽  
Vol 161 ◽  
pp. 761-776 ◽  
Author(s):  
Claudio Maccone
Keyword(s):  
Electromagnetic Waves ◽  
Space Missions ◽  
Gravitational Lens ◽  
The Sun ◽  
Space Antenna ◽  
Focal Distance ◽  
Large Space ◽  
The Earth ◽  
Space Antennas ◽  
New Space

AbstractSETI from space is currently envisaged in three ways: i) by large space antennas orbiting the Earth that could be used for both VLBI and SETI (VSOP and RadioAstron missions), ii) by a radiotelescope inside the Saha far side Moon crater and an Earth-link antenna on the Mare Smythii near side plain. Such SETIMOON mission would require no astronaut work since a Tether, deployed in Moon orbit until the two antennas landed softly, would also be the cable connecting them. Alternatively, a data relay satellite orbiting the Earth-Moon Lagrangian pointL2would avoid the Earthlink antenna, iii) by a large space antenna put at the foci of the Sun gravitational lens: 1) for electromagnetic waves, the minimal focal distance is 550 Astronomical Units (AU) or 14 times beyond Pluto. One could use the huge radio magnifications of sources aligned to the Sun and spacecraft; 2) for gravitational waves and neutrinos, the focus lies between 22.45 and 29.59 AU (Uranus and Neptune orbits), with a flight time of less than 30 years. Two new space missions, of SETI interest if ET’s use neutrinos for communications, are proposed.

Interpreting HVEM of muscle-cell impulse networks

1992 ◽  
Vol 50 (1) ◽  
pp. 126-127
Author(s):  
Paul DeCosta ◽  
Kyugon Cho ◽  
Stephen Shemlon ◽  
Heesung Jun ◽  
Stanley M. Dunn
Keyword(s):  
Structural Analysis ◽  
Muscle Cell ◽  
Electron Micrographs ◽  
Relative Size ◽  
Automatic Classification ◽  
Nerve Fibers ◽  
Analysis Algorithm ◽  
Structural Networks

Introduction: The analysis and interpretation of electron micrographs of cells and tissues, often requires the accurate extraction of structural networks, which either provide immediate 2D or 3D information, or from which the desired information can be inferred. The images of these structures contain lines and/or curves whose orientation, lengths, and intersections characterize the overall network.Some examples exist of studies that have been done in the analysis of networks of natural structures. In, Sebok and Roemer determine the complexity of nerve structures in an EM formed slide. Here the number of nodes that exist in the image describes how dense nerve fibers are in a particular region of the skin. Hildith proposes a network structural analysis algorithm for the automatic classification of chromosome spreads (type, relative size and orientation).

A Semantic Perspective on Omission Abstraction in ASP

2020 ◽  
Author(s):  
Zeynep G. Saribatur ◽  
Thomas Eiter
Keyword(s):  
Problem Solving ◽  
Program Analysis ◽  
Abstract Level ◽  
Answer Sets

The recently introduced notion of ASP abstraction is on reducing the vocabulary of a program while ensuring over-approximation of its answer sets, with a focus on having a syntactic operator that constructs an abstract program. It has been shown that such a notion has the potential for program analysis at the abstract level by getting rid of irrelevant details to problem solving while preserving the structure, that aids in the explanation of the solutions. We take here a further look on ASP abstraction, focusing on abstraction by omission with the aim to obtain a better understanding of the notion. We distinguish the key conditions for omission abstraction which sheds light on the differences to the well-studied notion of forgetting. We demonstrate how omission abstraction fits into the overall spectrum, by also investigating its behavior in the semantics of a program in the framework of HT logic.

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