Academic research is funded through taxpayer money, and, as an academic, I can assure you that much of it has a much lower impact than many open source projects.
I had a somewhat similar experience the day shellshock was announced on a layover in Atlanta flying between two different universities. I had been browsing the news and coding for maybe an hour after dinner at the battery-charging station in my completely empty terminal, and three clean-cut men in their late thirties sat down on all sides of me and started joking about how I was in trouble.
Long story short, after a few minutes of awkward chit chat where they repeatedly try to determine whether I "believed in absolutes", they let me know that, yes, they were "professional interrogators". They then all immediately got up and left for what they claimed was their flight to Minneapolis.
I have no idea who those three people were. I do agree that "unprofessional" is a good way to describe their behavior. I emailed a few colleagues about it but it was all too strange to speak publicly about. There was also a bit of a religious vibe to their questions, so there is a (small) chance that they were evangelicals claiming to be interrogators.
Almost nothing about the solver would need to change in order to support computation over GF(p), which suggests that someone should create a version of Lights Out / Inverter which cycles through a prime number of colors rather than just off/on.
Wikipedia has an article on this, http://en.wikipedia.org/wiki/Linear_equation_over_a_ring it would take a long time to read up the background to understand it, and I don't have the background to distill it to the exact result we want.
Note the wiki article references this book: Ideals, Varieties, and Algorithms by Cox, Little and O'Shea. This is a standard and approachable reference on this kind of topics.
Although this topic is interesting, I think it's best to treating it as a technology. Knowing it's existence and know when to apply them is good enough. Understanding how it works would be a big time sink and sadly doesn't give much useful insights.
I've manually verified that the binary matrix printed out by the following Octave/MATLAB routine provides solutions to Inverter. (NOTE: You may want to use the gflineq.m implementation from http://lost-contact.mit.edu/afs/cs.stanford.edu/package/matl...)
function M = Inverter(nx,ny)
A=eye(nx*ny,nx*ny);
for x=1:nx, for y=1:ny,
i=x+(y-1)*nx;
if( x ~= 1 ), A(i,i-1)=1; end;
if( x ~= nx ), A(i,i+1)=1; end;
if( y ~= 1 ), A(i,i-nx)=1; end;
if( y ~= ny ), A(i,i+nx)=1; end;
end; end;
b=ones(nx*ny,1);
s=gflineq(A,b);
M=zeros(ny,nx);
for x=1:nx, for y=1:ny, M(x,y)=s(x+(y-1)*nx); end; end;
return
A more effective approach might be to maintain a peer-reviewed ranking of various large tech companies based upon their patent history and to semi-regularly publicly base your employment decisions upon said list.
I'd argue that merely holding an egregious patent should not be the criterion but rather using it in a unprovoked manner. However, as I say this I wonder whether my bias is showing... against Microsoft (who I am frankly not very fond of) vs Google (who I like much more).
It is clear that with their investment in the patent troll, Microsoft is evil. However, Google has tried to hold up the evil companies by using standards essential patents as well. I can try to justify it in my mind but is Google really better than Microsoft? We have yet to see (as far as I know) Google sue anybody but isn't having a trove of nuclear weapons enough of a reason to distrust someone? It is not like they have to blatantly display it for it to be a part of negotiations (might be hand wrangling if you're on the wrong end of it).
I am conflicted because the more I think about it, the more I doubt my previous assertion. A pledge to not use frivolous patents in an aggressive way is not sufficient. However, wouldn't I rather Google or Twitter hold a frivolous patent knowing they likely won't sue me directly (I have very small dreams and I doubt I'd ever show up on their radar). If it keeps one more patent off of the hands of Intellectual Ventures (or even the likes of Amazon.com, Apple, and Microsoft), isn't that a good thing for the world?
Or, "Brian builds distributed-memory computers". Despite the misleading title, I think such a project would be a great tool for a parallel computing class. Such a machine would be roughly the same cost as a textbook and would be much more rewarding than running MPI on a multicore laptop/desktop.
Even if one buys the (demonstrably false) claim that all real-world problems are sparse, most sparse techniques (especially sparse-direct, and, to a limited degree, Krylov subspace methods) boil down to dense linear algebra on smaller matrices. When executing dense linear algebra on accelerators, it can be surprising just how carefully one must organize the computation in order to make the best use of the memory hierarchy. When I was writing these types of routines years ago, it was often beneficial to pre-/post-process certain operations, such as A^T B^T = C, by explicitly transposing either the input or output matrix (in my case, to ensure that reads from global memory could be coalesced in one of the inner loops).
With that said, an example of efficiently transposing dense matrices was one of the CUDA examples five years ago...
What makes satellite communication special? Is it okay to monitor the CEO of every communication company? If so, is it any different for non-US governments to monitor the CEO's of US tech companies?
I would bet that foreign countries (at least China, Russia, Israel and France) are at least trying to, and any competent CEO of an international communications company should be taking reasonable measures to protect their own and their clients confidentiality.
Arguing the rights or wrongs of the agency action misses the point: it's inevitable that someone is going to try it, so take counter measures.
This is why in the fuss over the NSA we shouldn't ignore the fact that Google, Facebook etc. are encouraging bad security practices by creating giant repositories of everyone's information. It just happens, this time, to be the NSA, but it could be any government, or even organised crime, and the only ways to stop all of them are by acting prudently in the first instance.
