667 research outputs found
Integrating a universal query mechanism into java
This thesis discusses design, architecture, and application of a universal query language embedded in Java. Utilizing various design patterns and Java\u27s polymorphism, the current result is a preprocessor that will convert an embedded language into compilable Java. The resulting Java utilizes a back{end developed for the queried data structure, capable of querying that structures internal data
An Introduction to Programming for Bioscientists: A Python-based Primer
Computing has revolutionized the biological sciences over the past several
decades, such that virtually all contemporary research in the biosciences
utilizes computer programs. The computational advances have come on many
fronts, spurred by fundamental developments in hardware, software, and
algorithms. These advances have influenced, and even engendered, a phenomenal
array of bioscience fields, including molecular evolution and bioinformatics;
genome-, proteome-, transcriptome- and metabolome-wide experimental studies;
structural genomics; and atomistic simulations of cellular-scale molecular
assemblies as large as ribosomes and intact viruses. In short, much of
post-genomic biology is increasingly becoming a form of computational biology.
The ability to design and write computer programs is among the most
indispensable skills that a modern researcher can cultivate. Python has become
a popular programming language in the biosciences, largely because (i) its
straightforward semantics and clean syntax make it a readily accessible first
language; (ii) it is expressive and well-suited to object-oriented programming,
as well as other modern paradigms; and (iii) the many available libraries and
third-party toolkits extend the functionality of the core language into
virtually every biological domain (sequence and structure analyses,
phylogenomics, workflow management systems, etc.). This primer offers a basic
introduction to coding, via Python, and it includes concrete examples and
exercises to illustrate the language's usage and capabilities; the main text
culminates with a final project in structural bioinformatics. A suite of
Supplemental Chapters is also provided. Starting with basic concepts, such as
that of a 'variable', the Chapters methodically advance the reader to the point
of writing a graphical user interface to compute the Hamming distance between
two DNA sequences.Comment: 65 pages total, including 45 pages text, 3 figures, 4 tables,
numerous exercises, and 19 pages of Supporting Information; currently in
press at PLOS Computational Biolog
Structure and Interpretation of Computer Programs
Structure and Interpretation of Computer Programs has had a dramatic impact on computer science curricula over the past decade. This long-awaited revision contains changes throughout the text. There are new implementations of most of the major programming systems in the book, including the interpreters and compilers, and the authors have incorporated many small changes that reflect their experience teaching the course at MIT since the first edition was published. A new theme has been introduced that emphasizes the central role played by different approaches to dealing with time in computational models: objects with state, concurrent programming, functional programming and lazy evaluation, and nondeterministic programming. There are new example sections on higher-order procedures in graphics and on applications of stream processing in numerical programming, and many new exercises. In addition, all the programs have been reworked to run in any Scheme implementation that adheres to the IEEE standard
Foundations of Programming Languages
This clearly written textbook provides an accessible introduction to the three programming paradigms of object-oriented/imperative, functional, and logic programming. Highly interactive in style, the text encourages learning through practice, offering test exercises for each topic covered. Review questions and programming projects are also presented, to help reinforce the concepts outside of the classroom. This updated and revised new edition features new material on the Java implementation of the JCoCo virtual machine
An Analytical Approach to Programs as Data Objects
This essay accompanies a selection of 32 articles (referred to in bold face in the text and marginally marked in the bibliographic references) submitted to Aarhus University towards a Doctor Scientiarum degree in Computer Science.The author's previous academic degree, beyond a doctoral degree in June 1986, is an "Habilitation à diriger les recherches" from the Université Pierre et Marie Curie (Paris VI) in France; the corresponding material was submitted in September 1992 and the degree was obtained in January 1993.The present 32 articles have all been written since 1993 and while at DAIMI.Except for one other PhD student, all co-authors are or have been the author's students here in Aarhus
Simple optimizing JIT compilation of higher-order dynamic programming languages
Implémenter efficacement les langages de programmation dynamiques demande beaucoup d’effort de développement.
Les compilateurs ne cessent de devenir de plus en plus complexes.
Aujourd’hui, ils incluent souvent une phase d’interprétation, plusieurs phases de compilation, plusieurs représentations intermédiaires et des analyses de code. Toutes ces techniques permettent d’implémenter efficacement un langage de programmation dynamique, mais leur mise en oeuvre est difficile dans un contexte où les ressources de développement sont limitées.
Nous proposons une nouvelle approche et de nouvelles techniques dynamiques permettant de développer des compilateurs performants pour les langages dynamiques avec de relativement bonnes performances et un faible effort de développement.
Nous présentons une approche simple de compilation à la volée qui permet d’implémenter un langage en une seule phase de compilation, sans transformation vers des représentations intermédiaires.
Nous expliquons comment le versionnement de blocs de base, une technique de compilation existante, peut être étendue, sans effort de développement significatif, pour fonctionner interprocéduralement avec les langages de programmation d’ordre supérieur, permettant d’appliquer des optimisations interprocédurales sur ces langages.
Nous expliquons également comment le versionnement de blocs de base permet de supprimer certaines opérations utilisées pour implémenter les langages dynamiques et qui impactent les performances comme les vérifications de type.
Nous expliquons aussi comment les compilateurs peuvent exploiter les représentations dynamiques des valeurs par Tagging et NaN-boxing pour optimiser le code généré avec peu d’effort de développement.
Nous présentons également notre expérience de développement d’un compilateur à la volée pour le langage de programmation Scheme, pour montrer que ces techniques permettent effectivement de construire un compilateur avec un effort moins important que les compilateurs actuels et qu’elles permettent de générer du code efficace, qui rivalise avec les meilleures implémentations du langage Scheme.Efficiently implementing dynamic programming languages requires a significant development
effort. Over the years, compilers have become more complex. Today, they typically include
an interpretation phase, several compilation phases, several intermediate representations and
code analyses. These techniques allow efficiently implementing these programming languages
but are difficult to implement in contexts in which development resources are limited. We
propose a new approach and new techniques to build optimizing just-in-time compilers for
dynamic languages with relatively good performance and low development effort.
We present a simple just-in-time compilation approach to implement a language with
a single compilation phase, without the need to use code transformations to intermediate
representations. We explain how basic block versioning, an existing compilation technique,
can be extended without significant development effort, to work interprocedurally with higherorder
programming languages allowing interprocedural optimizations on these languages. We
also explain how basic block versioning allows removing operations used to implement dynamic
languages that degrade performance, such as type checks, and how compilers can use Tagging
and NaN-boxing to optimize the generated code with low development effort. We present our
experience of building a JIT compiler using these techniques for the Scheme programming
language to show that they indeed allow building compilers with less development effort
than other implementations and that they allow generating efficient code that competes with
current mature implementations of the Scheme language
Compiler of a Language with User-Defined Syntax for New Constructs
Tato práce si klade za cĂl navrhnout a implementovat experimentálnĂ programovacĂ jazyk s podporou uĹľivatelsky definovanĂ˝ch syntaktickĂ˝ch konstrukcĂ. NovĂ˝ jazyk je kompilován do nativnĂ binárnĂ podoby a vyĹľaduje statickou typovou disciplĂnu v dobÄ› pĹ™ekladu. Jazyk se skládá ze dvou hlavnĂch komponent. PrvnĂ z nich je minimalistickĂ© jádro zaloĹľenĂ© na principech zásobnĂkovÄ› orientovanĂ˝ch jazykĹŻ. Druhou částĂ je mechanismus pro definici novĂ˝ch syntaktickĂ˝ch konstrukcĂ uĹľivatelem. PotĂ© jsou shrnuty poznatky nabytĂ© pĹ™i návrhu a experimentovánĂ s prototypem pĹ™ekladaÄŤe tohoto jazyka.This project aims to design and implement an experimental programming language. The main feature of the language shall be the ability of the user to define new syntactic constructs. The language shall be statically typed and compiled to a native binary form. The language consists of two parts. The first part is a minimalistic core based on the principles of stack-oriented languages. The second part is a mechanism that lets users define new syntactic constructs. Then we elaborate on findings that have risen from design and experiments performed with the prototype implementation of the language.
GNU epsilon - an extensible programming language
Reductionism is a viable strategy for designing and implementing practical
programming languages, leading to solutions which are easier to extend,
experiment with and formally analyze. We formally specify and implement an
extensible programming language, based on a minimalistic first-order imperative
core language plus strong abstraction mechanisms, reflection and
self-modification features. The language can be extended to very high levels:
by using Lisp-style macros and code-to-code transforms which automatically
rewrite high-level expressions into core forms, we define closures and
first-class continuations on top of the core. Non-self-modifying programs can
be analyzed and formally reasoned upon, thanks to the language simple
semantics. We formally develop a static analysis and prove a soundness property
with respect to the dynamic semantics. We develop a parallel garbage collector
suitable to multi-core machines to permit efficient execution of parallel
programs.Comment: 172 pages, PhD thesi
A Tracing JIT Compiler for Erlang using LLVM
We have modified the Erlang runtime to add support for a tracing just-in-time (JIT) compiler, similar to Mozilla’s TraceMonkey. Tracing is a technique to augment an existing interpreter with a JIT simply by recording the instructions executed during a loop iteration, and then generate optimized native code from this. Tracing compilers are particularly suited to optimize number crunching tight loops, an area where Erlang traditionally has been lacking. We make use of the LLVM compiler library to optimize and emit native code. In micro benchmarks we show some major improvements, reducing execution time by up to 75%. However, from an engineering point of view, we conclude that the effort of an industrial strength implementation would be substantial – essentially reimplementing large parts of Erlang’s interpreter – and discuss a potential solution based on recent research in the area.Nästan alla moderna programspråk använder en interpretator – en flexibel och praktisk om än långsam lösning. Vi prövar ett enkelt sätt att kraftigt öka prestandan på Erlangs interpretator
Liveness-Based Garbage Collection for Lazy Languages
We consider the problem of reducing the memory required to run lazy
first-order functional programs. Our approach is to analyze programs for
liveness of heap-allocated data. The result of the analysis is used to preserve
only live data---a subset of reachable data---during garbage collection. The
result is an increase in the garbage reclaimed and a reduction in the peak
memory requirement of programs. While this technique has already been shown to
yield benefits for eager first-order languages, the lack of a statically
determinable execution order and the presence of closures pose new challenges
for lazy languages. These require changes both in the liveness analysis itself
and in the design of the garbage collector.
To show the effectiveness of our method, we implemented a copying collector
that uses the results of the liveness analysis to preserve live objects, both
evaluated (i.e., in WHNF) and closures. Our experiments confirm that for
programs running with a liveness-based garbage collector, there is a
significant decrease in peak memory requirements. In addition, a sizable
reduction in the number of collections ensures that in spite of using a more
complex garbage collector, the execution times of programs running with
liveness and reachability-based collectors remain comparable
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