nicksdjohnson

7 ms·

31.
Any page loaded in IE can track your mouse movements anywhere(spider.io)
292 points by nicksdjohnson 14y ago|161 comments
32.
by nicksdjohnson 14y ago
I'm guessing you're talking about the SRAM-based alternative I discussed at the end? Yes, that would be an option, as would an SD card. 64Mb would be enough for plenty of 256 kilobit slices. I do prefer the idea of using EEPROM if I was goi
33.
by nicksdjohnson 14y ago
I got them done at Hackvana (hackvana.com, or #hackvana on irc.freenode.net); similar prices to Seeed, and excellent customer service. I'm not sure about the maximum speed. The flipflop, for instance, has a delay of 14ns; if we take that as
34.
by nicksdjohnson 14y ago
Enough parts for 20 boards cost me about 100 pounds; the board fabrication cost about $60, but a lot of that was because I wanted it in a rush. All up, that works out to about 8 pounds, or 13 USD per board. It'd be somewhat cheaper - around
35.
by nicksdjohnson 14y ago
I probably overdid the solder a bit, but there's no way most of the pads had enough solder on them for SOICs without my adding any. I've soldered SOICs before, but this is by far the largest volume I've done in a sitting. As I mentioned bri
36.
by nicksdjohnson 14y ago
Have you read the papers I linked in detail? Some of them, such as HyperLogLog, provide corrections to give better estimates for small sets, and although I can't follow the proof in its entirety, they claim to be more efficient than the alt
37.
by nicksdjohnson 14y ago
A friend mentioned the existence of this, but I couldn't find it myself. Thanks for pointing it out. All the algorithms can process data in a streaming fashion, though - they only require a single pass.
38.
by nicksdjohnson 14y ago
I actually cover that in the post (well, more or less - I talk about hashing to remove bias, after talking about the 'min element' algorithm. According to the papers cited, though, taking the count of leading zeroes is more space efficient,
39.
by nicksdjohnson 14y ago
Very nice, thanks! It might be too similar for a post all of its own, but I think it'd be a worthy followup to this post.
40.
Damn Cool Algorithms: Cardinality Estimation(blog.notdot.net)
233 points by nicksdjohnson 14y ago|30 comments
41.
by nicksdjohnson 14y ago
I can't express how awesome it is to hear that.
42.
by nicksdjohnson 14y ago
Actually, it's even worse than that - with a rateless code like Fountain codes, you can generate an effectively unlimited number of encoded blocks, making pregeneration of hashes for them all completely impractical. In all other particulars
43.
by nicksdjohnson 14y ago
Absolutely. It's still pretty expensive to take a 257-bit power of a 1024-bit number with modular exponentiation, though.
44.
Dear HN: What interesting algorithms would you like to read about?
12 points by nicksdjohnson 14y ago|8 comments
45.
by nicksdjohnson 15y ago
You should write this up somewhere and post it to HN and the App Engine Reddit. Getting geospatial right is hard, and it sounds like you've done a good job.
46.
by nicksdjohnson 15y ago
That's a good question. I can't point to published figures, since the 2.7 runtime is still fairly new, but I can say that based on both my personal experience and based on fairly basic reasoning, the per-thread memory overhead is definitely
47.
by nicksdjohnson 15y ago
One gets from 31 cpu hours to 879 instance hours if your average CPU utilization is about 3.5% - see my other post for details.
48.
by nicksdjohnson 15y ago
Hi folks, I'm on the App Engine team, and I just wanted to clarify one thing: The main difference between CPU hours and Instance hours is that CPU hours are charged based on CPU usage, while instance hours are based on wallclock time. The h