Lorin Hochstein

Ramblings about software, research and other things

Archive for December 2011

IEEE and the newspaper industry

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Ian Sommerville went on a tear the other day about IEEE not supporting open access content. I suspect that IEEE uses the revenues it gets from publication subscriptions to subsidize other activities like conferences. I think the open access model for research publications is inevitable, especially in tech-savvy fields like electrical engineering and computer science. When that happens,  the IEEE may find itself in the position that the newspapers did when one of their profit centers (classifieds) got disrupted by free online services like Craigslist, making it difficult to fund the cost centers (news reporting).

Mind you, if free journals and fewer subsidized IEEE conferences means that computer science shifts from being conference-oriented to being journal-oriented like the rest of academia, it will probably be a benefit to the CS research community. But IEEE will have to either reinvent itself or go the way of the local newspaper.

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Written by Lorin

December 21, 2011 at 4:31 pm

Posted in research, software

Bifurcation

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The IT community:

Shared memory programming (pthreads) is awful! Message-passing (Erlang) would make our lives so much easier!

The high-performance computing community:

Message-passing (MPI) is awful! Shared-memory programming (OpenMP, PGAS) would make our lives so much easier!

See also.

Written by Lorin

December 21, 2011 at 9:22 am

Posted in software

Weird and gross

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I always get a kick out of the error message that appears when trying to install TeX with Homebrew.

$ brew install tex
Error: No available formula for tex
Installing TeX from source is weird and gross, requires a lot of patches,
and only builds 32-bit (and thus can't use Homebrew deps on Snow Leopard.)

We recommend using a MacTeX distribution: http://www.tug.org/mactex/

Written by Lorin

December 20, 2011 at 10:06 pm

Posted in software

A preliminary empirical study to compare MPI and OpenMP

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Part of my dissertation work involved controlled experiments to measure the effect of parallel programming model on programmer productivity. Unfortunately, I didn’t have much luck getting these studies published. I just made one of them into a tech report (after being rejected from multiple journals), it’s an experiment that measures the difference in programming effort of MPI vs OpenMP on a programming task.  You can judge for yourself whether it’s any good. Here’s the abstract:

Context: The rise of multicore is bringing shared-memory parallelism to the masses. The community is struggling to identify which parallel models are most productive.

Objective: Measure the effect of MPI and OpenMP models on programmer productivity.

Design: One group of programmers solved the sharks and fishes problem using MPI and a second group solved the same problem using OpenMP, then each programmer switched models and solved the same problem again. The participants were graduate students in an HPC course.

Measures: Development effort (hours), program correctness (grades), program performance (speedup versus serial implementation).

Results: Mean OpenMP development time was 9.6 hours less than MPI (95% CI, 0.37-19 hours), a 43% reduction. No statistically significant difference was observed in assignment grades. MPI performance was better than OpenMP performance for 4 out of the 5 students that submitted correct implementations for both models.

Conclusions: OpenMP solutions for this problem required less effort than MPI, but insufficient power to measure the effect on correctness. The performance data was insufficient to draw strong conclusions but suggests that unoptimized MPI programs perform better than unoptimized OpenMP programs, even with a similar parallelization strategy. Further studies are necessary to examine different programming problems, models, and levels of programmer experience.

Written by Lorin

December 20, 2011 at 9:12 pm

Posted in research, software

Newer interfaces aren’t always better

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I was at the car dealer today, dropping of the car for safety and emission inspections. The service advisor brought up a VT100-style terminal interface on her computer to punch in the service details. She made an offhand remark about a problem with the computer system today, and slammed her way through some text screens on the numeric keypad.

If that system was implemented today, it would have a web interface. It would be more pleasant to look at, and easier for a new employee to learn. And, yet, once that employee became proficient, I’d wager that tasks would take longer using a web interface compared to the original terminal interface.

Written by Lorin

December 20, 2011 at 10:52 am

Posted in software

Rankings are hard

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Good Communications of the ACM article on the challenge of generating reliable university rankings. I wonder if NSF funds research to solve this problem.

Written by Lorin

December 18, 2011 at 9:16 pm

Posted in research

Apple and published research

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Written by Lorin

December 18, 2011 at 6:30 pm

Posted in research, software