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typodupeerror

Comment How about errors and debugging? (Score 2)159

I feel that one of the weakest points of R is the error handling, reporting, and debugging available.  Do you have advice on tools or techniques for people coding in R (aside from using RStudio?  Are there plans for improvements in this area?  The current facilities are reminiscent, at least to me, of using gdb back in the 1990s.

I have in mind cases like the following, in which a confusion about list access using the [ operator (when the [[ should have been used) provides a cryptic error message with no traceback available.

> symlog_scaler <- list(linear_to=2.5,  abscissa=2.0,
+    scaling_function=function(x,linear_to=2.5,abscissa=2.0){
+        y <- x; linear_to = abs(linear_to); big_ix = (linear_to<x)
+        y[big_ix] = linear_to + log(1+(x[big_ix] - linear_to), base=abscissa)
+        small_ix = (-linear_to>x)
+        y[small_ix] = -(linear_to + log(1+(-x[small_ix] - linear_to),base=abscissa))
+        y})
> symlog_scaler\$scaling_function(-5:5)
[1] -4.307355 -3.821928 -3.084963 -2.000000 -1.000000  0.000000  1.000000  2.000000  3.084963
[10]  3.821928  4.307355
> symlog_scaler['scaling_function'](-5:5)
Error: attempt to apply non-function
> traceback()
No traceback available
>

Comment Are symmetries left our because of superko? (Score 2)117

Looking into the paper, we see that with L(2,2)=81-16-8=57 various positions that are symmetric transforms of each other are considered distinct. For example, on sees this in the upper right and lower left corners of Figure 1. Now, it's true that superko will break some of that symmetry, but not all of it. How much complexity disappears with more accounting for symmetry?

Comment Lacking objective quality metric (Score 1)84

To quantify the degree of obfuscation, they have precise computational metrics based on their stylometric algorithms. But to judge the quality of the obfuscation, there is no objective metrics. Instead

To measure soundness and properness, obfuscations will be sampled and handed out to participants for peer-review.

which seems to me to make the contest rather less meaningful. Why not just peer review the quality of all obfuscations exceeding some minimum standard?

Comment Re:OpenWRT for \$25 (Score 1)247

That's from 2002 and I wonder if that's even true of Cisco anymore. I have watched Cisco firewalls hard crash with too many connections on 256 mb ram.

This site seems to indicate 16 KB per connection, which doesn't leave much once you've subtracted the memory needed for OS/daemons etc..

That would be bad. However, I see that later in that document there's a section entitled Ideal case: firewalling-only machine where it says:

sizeof(struct ip_conntrack) is around 300 bytes on i386 for 2.6.5, but heavy development around 2.6.10 make it vary between 352 and 192 bytes!

For safety we might want to assume recent kernels have doubled that again, perhaps to 800 bytes. That still puts us under 2MB of RAM for 2000 connections. For greater certainty, I tried to check the kernel v4.3 source and sizeof(), but NAT has changed drastically in the 4.x series kernels.

Comment Re:OpenWRT for \$25 (Score 1)247

This is not as good as it appears. Their "Enterprise router" has 128 mb ram and there is no way that's going to hold up to a significant amount of simultaneous (connections let alone the 64 mb ram that most of the devices have,

Is that really an issue? According to this, each NAT entry needs <200Bytes, in which case 2000 simultaneous connections (plenty for most any single dwelling) require less than 1MB RAM.

It wasn't that long ago that even enterprise-class routers got by on 32MB or less of RAM.

Comment OpenWRT for \$25 (Score 3, Informative)247

These guys sell a tiny "travel router" (or just the board if you like) that goes for \$25 on Amazon. Crucially it has 2 ethernet ports (albeit only 100Mbits), along with Wifi. It ships with their modified version of OpenWRT but takes only a couple minutes to flash to the latest fully open-source version. From there, going further into homebrew is trivially easy. I find it a better starting point than a raw Linux distro, and the low power consumption just cannot be beat. If you want to go Linux and don't have a fat pipe, I recommend it.

Comment Re:People actually *like* Python whitespace? (Score 1)339

I find that Python is attractive, and works extremely well, for people well-suited to information-dense representation of ideas. This includes physicists, mathematicians and other folks who are used to that property of the hard sciences literature. For software architects and developers, its attractiveness is more if a mixed bag, where many of those folks are more comfortable and productive with a greater amount of structure.

Comment Re:Somewhat hyped (Score 1)48

It's hard to say without doing all the implementation work, but the paper does say that the algo is "...general enough to describe both local polynomial and Gaussian process approximations..." and there is a section called "Local Gaussian process surrogates". So, they do in fact incorporate this in the larger framework of their algo.

In fact, they claim "...that the accuracy is nearly identical for all the cases, but the approximate chains use fewer evaluations of the true model, reducing costs by more than an order of magnitude for quadratic or Gaussian process approximations (Figure 10b)."

Indeed, though that quote is simply pointing out that the relative performance of their algorithm is at its best with its mode set to local Gaussian approximations.

Comment Biased summary (Score 3, Insightful)121

...confirmed their own questionable behavior...

I am a US citizen as frustrated about unauthorized domestic surveillance as anyone. But this summary goes too far. Finding, keeping and using vulnerabilities is exactly what the NSA is supposed to do, and there is nothing questionable about that behavior.
If the submitter wants the government to have a group that finds and discloses vulnerabilities as part of its remit, then make a case for creating such a group. Don't saddle the NSA with the job.

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