"This page is not intended to replace reading the Xgrid Admin Manual but rather to supplement it. Additions here concisely hit highlights and integrate issues beyond what is covered in the frequently asked questions."

Stencil computations, involving operations over the elements of an array, are a common programming pattern in scientific computing, games, and image processing. As a programming pattern, stencil computations are highly regular and amenable to optimisation and parallelisation. However, general-purpose languages obscure this regular pattern from the compiler, and even the programmer, preventing optimisation and obfuscating (in)correctness. This paper furthers our work on the Ypnos domain-specific language for stencil computations embedded in Haskell. Ypnos allows declarative, abstract specification of stencil computations, exposing the structure of a problem to the compiler and to the programmer via specialised syntax. In this paper we show the decidable safety guarantee that well-formed, well-typed Ypnos programs cannot index outside of array boundaries. Thus indexing in Ypnos is safe and run-time bounds checking can be eliminated. Program information is encoded as types, using the advanced type-system features of the Glasgow Haskell Compiler, with the safe-indexing invariant enforced at compile time via type checking.

"Task reassignments in 2D mesh-connected systems (2D-MSs) have been researched and simulated for several decades. We propose a hierarchical 2D mesh-connected system (2D-HMS) in order to exploit the regular nature of a 2D-MS. In our approach priority-based task assignments and reassignments in a 2D-HMS are represented by tableaux and their algorithms. We provide examples of priority-based task reassignments in a 2D-HMS in which task relocations are simply reduced to a jeu de taquin slide."

"Storage optimization in distributed environments is a major concern when talking about reliability in this kind of schemes. Although replication is the most used option, erasure coding is a more optimized one.
However, erasure coding uses a lot of bandwidth to replace one node. In a dynamic scheme, where nodes enter and leave the system frequently, bandwidth use could be an important drawback.
Regenerating Codes introduced by Dimakis et al. minimize the code repair problem by applying Network Coding to the distributed storage scheme. However finding the coefficients for the linear combinations used to replace a node is not easy, specially for the systematic case, and must be calculated for each new node fail.…"

"The use of Graphics Processing Units (GPUs) in scientific computing is becoming increasingly common. GPUs are low cost parallel processors that can readily be exploited for many types of general purpose computation. Recently, the computational intelligence community has started to develop for the GPU platform. This web page is primarily dedicated to the use of GPUs as a platform for Genetic Programming. "

"Spot Instances are a new way to purchase and consume Amazon EC2 Instances. They allow customers to bid on unused Amazon EC2 capacity and run those instances for as long as their bid exceeds the current Spot Price. The Spot Price changes periodically based on supply and demand, and customers whose bids meet or exceed it gain access to the available Spot Instances. Spot Instances are complementary to On-Demand Instances and Reserved Instances, providing another option for obtaining compute capacity."

"The Ruby Development Center contains sample code, documentation, tools, and additional resources to help you build applications on Amazon Web Services."

"It boils down to this: GitHub is a warzone. We are constantly overloaded and rely very, very heavily on our queue. If it's backed up, we need to know why. We need to know if we can fix it. We need workers to not get stuck and we need to know when they are stuck.

We need to see what the queue is doing. We need to see what jobs have failed. We need stats: how long are workers living, how many jobs are they processing, how many jobs have been processed total, how many errors have there been, are errors being repeated, did a deploy introduce a new one?

We need a background job system as serious as our web framework. I highly recommend DelayedJob to anyone whose site is not 50% background work.

But GitHub is 50% background work."

"In a CouchDB-enabled web, data-flows don't have to be centralized, which means friends can communicate without going through a fixed domain. This makes the web more efficient. It also means I can make data available to my social network without relying on 3rd-party services."

"The Open Cloud Consortium (OCC) is a member driven organization that:

Supports the development of standards for cloud computing and frameworks for interoperating between clouds;
develops benchmarks for cloud computing;
supports reference implementations for cloud computing, preferably open source reference implementations;
manages a testbed for cloud computing called the Open Cloud Testbed;
sponsors workshops and other events related to cloud computing."

Proof-of-concept of distributed population-based metaheuristics running on a number of phones.

Frickin' expensive. But perhaps, maybe, worthwhile.

I love this. Love it. Lee and Jon, you made my day.

Important.