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Submission + - Same programs + Different computers = Different weather forecasts (ametsoc.org)

Submitted by knorthern knight
knorthern knight writes: Most major weather services (US NWS, Britain's Met Office, etc) have their own supercomputers, and their own weather models. But there are some models which are used globally. A new paper has been published, comparing outputs from one such program on different machines around the world. Apparently, the same code, running on different machines, can produce different outputs due to accumulation of differing round-off errors. The handling of floating-point numbers in computing is a field in its own right http://docs.oracle.com/cd/E19957-01/806-3568/ncg_goldberg.html

The paper apparently deals with 10-day weather forecasts. Weather forecasts are generally done in steps of 1 hour. I.e. the output from hour 1 is used as the starting condition for the hour 2 forecast. The output from hour 2 is used as the starting condition for hour 3, etc.

The paper is paywalled, but the abstract at http://journals.ametsoc.org/doi/abs/10.1175/MWR-D-12-00352.1 says...

The global model program (GMP) of the Global/Regional Integrated Model system (GRIMs) is tested on 10 different computer systems having different central processing unit (CPU) architectures or compilers. There exist differences in the results for different compilers, parallel libraries, and optimization levels, primarily due to the treatment of rounding errors by the different software systems. The system dependency, which is the standard deviation of the 500-hPa geopotential height averaged over the globe, increases with time. However, its fractional tendency, which is the change of the standard deviation relative to the value itself, remains nearly zero with time. In a seasonal prediction framework, the ensemble spread due to the differences in software system is comparable to the ensemble spread due to the differences in initial conditions that is used for the traditional ensemble forecasting.

Submission + - Obama promise to 'Protect Whistleblowers' disappears from change.gov (sunlightfoundation.com)

Submitted by Anonymous Coward
An anonymous reader writes: The Sunlight Foundation noticed that the change.gov website set up by the Obama transition team in 2008 after the election had its original content removed. "It wouldn't be the first time administration positions disappear from the internet when they become inconvenient descriptions of their assurances."

"Protect Whistleblowers: Often the best source of information about waste, fraud, and abuse in government is an existing government employee committed to public integrity and willing to speak out. Such acts of courage and patriotism, which can sometimes save lives and often save taxpayer dollars, should be encouraged rather than stifled. We need to empower federal employees as watchdogs of wrongdoing and partners in performance. Barack Obama will strengthen whistleblower laws to protect federal workers who expose waste, fraud, and abuse of authority in government. Obama will ensure that federal agencies expedite the process for reviewing whistleblower claims and whistleblowers have full access to courts and due process."

Comment Re:Congratulations! (Score 1) 5

by mcgrew (#44398457) Attached to: 2001 essay of mine front paged at Long Form

Will do. I'm still editing and making minor changes so it will probably be a few more months, but I'll email a PDF when I send it to the printers. I'm publishing under the same license Cory Doctorow uses; he credits that with his status as a NYT best seller, and I think I write better than he does (of course, I'm probably the only one that thinks that).

Comment Re:Scams against Cisco? (Score 1) 74

branding the counterfeit gear(I'm just guessing that

I'm offtopic here (checking the "no bonus" boxes), but I notice you continue to omit the needed space between "gear" and "(I'm just guessing)". Your comments would be more readable (and more easily taken seriously) if you followed centuries old proper formatting rules.

Minor nit, far better than some folks here's "todays special's" or "there car is over their". If I were moderating I'd probably have modded you up despite the rather annoying mistake.

Comment Re:I'll vote for a libertarian when I see one (Score 1) 15

by mcgrew (#44392405) Attached to: Edward Snowden vs President Alan Richmond

As for the greens, I'm OK with them for the most part. I just don't see pot as being an important enough issue to warrant establishing an entire political party around it.

Actually, I think the Greens' main platform is the environment.

I'll even go so far as to say that the first presidential candidate in 2016 who declares universal single-payer health care as a part of their platform will get my vote as long as I don't have to write them in.

We had a Congressional candidate last election, a medical doctor, who wanted medicare for everyone. Unfortunately, the tea party candidate beat him.

I'd like to have a labor party here.

Submission + - Multi-purpose wings allow flying robot to walk across rough terrain (robohub.org) 1

Submitted by Sabine Hauert
Sabine Hauert writes: The Deployable Air Land Exploration Robot (DALER) uses its own wings to crawl and roll over a variety of terrains. Using a self-adjusting structure to transform its wings into rotating arms, the robot is able to flip, rotate and navigate its way around and over obstacles on the ground. Sharing the wings across different modes of locomotion reduces the amount of infrastructure and weight the robot must carry, thus improving flight performance. The ability to adapt to a variety of environments is important in search and rescue operations, where both air and ground searching may be required.

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