2,088 research outputs found
DALiuGE: A Graph Execution Framework for Harnessing the Astronomical Data Deluge
The Data Activated Liu Graph Engine - DALiuGE - is an execution framework for
processing large astronomical datasets at a scale required by the Square
Kilometre Array Phase 1 (SKA1). It includes an interface for expressing complex
data reduction pipelines consisting of both data sets and algorithmic
components and an implementation run-time to execute such pipelines on
distributed resources. By mapping the logical view of a pipeline to its
physical realisation, DALiuGE separates the concerns of multiple stakeholders,
allowing them to collectively optimise large-scale data processing solutions in
a coherent manner. The execution in DALiuGE is data-activated, where each
individual data item autonomously triggers the processing on itself. Such
decentralisation also makes the execution framework very scalable and flexible,
supporting pipeline sizes ranging from less than ten tasks running on a laptop
to tens of millions of concurrent tasks on the second fastest supercomputer in
the world. DALiuGE has been used in production for reducing interferometry data
sets from the Karl E. Jansky Very Large Array and the Mingantu Ultrawide
Spectral Radioheliograph; and is being developed as the execution framework
prototype for the Science Data Processor (SDP) consortium of the Square
Kilometre Array (SKA) telescope. This paper presents a technical overview of
DALiuGE and discusses case studies from the CHILES and MUSER projects that use
DALiuGE to execute production pipelines. In a companion paper, we provide
in-depth analysis of DALiuGE's scalability to very large numbers of tasks on
two supercomputing facilities.Comment: 31 pages, 12 figures, currently under review by Astronomy and
Computin
Cohomological Hall algebras, vertex algebras and instantons
We define an action of the (double of) Cohomological Hall algebra of
Kontsevich and Soibelman on the cohomology of the moduli space of spiked
instantons of Nekrasov. We identify this action with the one of the affine
Yangian of . Based on that we derive the vertex algebra at
the corner of Gaiotto and Rapcak. We conjecture
that our approach works for a big class of Calabi-Yau categories, including
those associated with toric Calabi-Yau -folds.Comment: 72 pages, 4 figures, v2: Added some clarifications and updated
references 73 pages, 4 figures, v3: Corrected typos and clarified some minor
point
The quotient in preorder theories
Seeking the largest solution to an expression of the form Ax 64 B is a common task in several domains of engineering and computer science. This largest solution is commonly called quotient. Across domains, the meanings of the binary operation and the preorder are quite different, yet the syntax for computing the largest solution is remarkably similar. This paper is about finding a common framework to reason about quotients. We only assume we operate on a preorder endowed with an abstract monotonic multiplication and an involution. We provide a condition, called admissibility, which guarantees the existence of the quotient, and which yields its closed form. We call preordered heaps those structures satisfying the admissibility condition. We show that many existing theories in computer science are preordered heaps, and we are thus able to derive a quotient for them, subsuming existing solutions when available in the literature. We introduce the concept of sieved heaps to deal with structures which are given over multiple domains of definition. We show that sieved heaps also have well-defined quotients
The Quotient in Preorder Theories
Seeking the largest solution to an expression of the form A x <= B is a
common task in several domains of engineering and computer science. This
largest solution is commonly called quotient. Across domains, the meanings of
the binary operation and the preorder are quite different, yet the syntax for
computing the largest solution is remarkably similar. This paper is about
finding a common framework to reason about quotients. We only assume we operate
on a preorder endowed with an abstract monotonic multiplication and an
involution. We provide a condition, called admissibility, which guarantees the
existence of the quotient, and which yields its closed form. We call preordered
heaps those structures satisfying the admissibility condition. We show that
many existing theories in computer science are preordered heaps, and we are
thus able to derive a quotient for them, subsuming existing solutions when
available in the literature. We introduce the concept of sieved heaps to deal
with structures which are given over multiple domains of definition. We show
that sieved heaps also have well-defined quotients.Comment: In Proceedings GandALF 2020, arXiv:2009.0936
The C++0x "Concepts" Effort
C++0x is the working title for the revision of the ISO standard of the C++
programming language that was originally planned for release in 2009 but that
was delayed to 2011. The largest language extension in C++0x was "concepts",
that is, a collection of features for constraining template parameters. In
September of 2008, the C++ standards committee voted the concepts extension
into C++0x, but then in July of 2009, the committee voted the concepts
extension back out of C++0x.
This article is my account of the technical challenges and debates within the
"concepts" effort in the years 2003 to 2009. To provide some background, the
article also describes the design space for constrained parametric
polymorphism, or what is colloquially know as constrained generics. While this
article is meant to be generally accessible, the writing is aimed toward
readers with background in functional programming and programming language
theory. This article grew out of a lecture at the Spring School on Generic and
Indexed Programming at the University of Oxford, March 2010
On Some Quadratic Algebras I : Combinatorics of Dunkl and Gaudin Elements, Schubert, Grothendieck, Fuss-Catalan, Universal Tutte and Reduced Polynomials
We study some combinatorial and algebraic properties of certain quadratic
algebras related with dynamical classical and classical Yang-Baxter equations.
One can find more details about the content of present paper in Extended
Abstract.Comment: Dedicated to the memory of Alain Lascoux (1944-2013). Preprint
RIMS-1817, 172 page
- …