If all you need to do is create a negative version of pre-existing image, you can use ImageMagick on the command line:

$ converge in.png -negate out.png

Pashin' it doon

It's hard getting something that sounds consistently good in all listening environments - I've seen cases where music is offered in digital format either as 'play anywhere' loud .mp3s or 24-bit high dynamic-range .flacs for DJs, but most commercial music is mastered for the poorest environments (in the car, over the radio).

Getting a good master is very important - I'm reminded of a story I heard about an album that was mastered by the artist, and pressed to CD with a high-pitched whine over the top which the artist hadn't been able to hear - like Aphex Twin's Ventolin, but unintentional.

> most commercial music is mastered for the poorest environments (in the car, over the radio).

One thing to consider (at least, that I consider when mastering my own music) is what processing might be applied in the future.

I helped out at the radio station back in college, and you can see the signal chain for audio coming from the studio onto the airwaves. Radio stations often add at least 9 dB of gain via compression, sometimes more. So, if you want a quick and dirty "how does my track sound on the radio?" toss on a master limiter and give yourself 12 dB of gain, then see whether it sounds as you intend (then don't forget to remove the gain after you've made your tweaks).

> a story I heard about an album that was mastered by the artist, and pressed to CD with a high-pitched whine over the top which the artist hadn't been able to hear

Funnily enough, this was common in albums recorded in the 80s and 90s. Reason? CRT monitors were used in the studio, and the high-pitched sound of the screens would get picked up by the microphones. A little discussion here: http://forums.stevehoffman.tv/threads/high-frequency-tones-o...

Aside from being one of the singers involved, I make archival recordings of my community chorus's performances. In my case, I use a rather simple setup: a pair of small-diaphragm condenser mics (usually but not always set up in the ORTF configuration), a preamp, and a digital recorder. Audacity has all of the capabilities I need for the editing/mastering phase.

One thing I've noticed is that the dynamic range of a live choral performance tends to exceed the useful range of typical consumer audio equipment[1], and it's necessary for me to deal with audience applause (usually by temporary dropping its level), and I also need to carefully apply some limiting on peaks - and sometimes a little bit of compression can work wonders.

If I resort to compression, I typically use parallel ("New York") compression, in which the uncompressed audio gets mixed with the compressed audio. It can be a bit fiddly, since it's necessary to apply the right settings to the compressed track, and to find the right proportion of compressed to uncompressed audio in the final mix.

The finished result tends to sound a bit more "up close" than the raw recording, which can be useful when I'm forced to record from the back of the room.

Even so, I find that I have to turn the volume up quite a bit higher than I would for typical pop music (especially since the Loudness War).

[1]What I mean above is, "being able to listen to the recording at a reasonable level without the peaks distorting or blowing out your speakers."

Certain models of SSL consoles could produce a ~15khz ringing in the master output. I had this exact thing happen to me, and eventhough my hearing good enough to hear it clearly once I was paying attention, in the middle of working I didn't notice it at all, until I got home. I heard that it happened on some Peter Gabriel records (he was famously a fan of SSL consoles). Probably wouldn't be too hard to remove in mastering, incidentally.

Actually, the car is one of the best listening environments most people have ready access to - an enclosed space (perhaps dolby 5.1) with sufficient bass, with all the channels pointed more or less equally at your head. Many audio engineers use a car as a reference point.

I dunno. Between road noise and my crappy speakers, GP made perfect sense to me. :)

The shell '>' redirect will truncate the file first of all, for example:

  echo "foo" > message.txt ; ( sleep 3 ; echo "bar" ) > message.txt & echo "message: '$( cat message.txt )'"

will print "message ''", not "message 'foo'".

Interestingly, that means that the 'openssl' command might have been working with an empty signature.

Of course, he might have just aliased 'openssl' as 'echo "Verified OK"' ...

Vim's built-in encryption is pretty useful, although the default cipher is weak (you can override this in the vimrc).

I didn't know vim had any built-in encryption. I've been using this for a while: https://gist.github.com/ipartola/ea5a88675cc548425ecb

Basically, I just do something like `vim foo.txt.gpg` and it transparently encrypts/decrypts the contents.

I always liked the quantum bogo-sort algorithm:

1) Randomise list

2) if list not in correct order, destroy the universe

The universe that's left will have the correct answer.

Note that the random source should be truly (in quantum sense) random for this to work.

"Help, I used a PRNG and I accidentally destroyed all known universes"

Better check StackOverflow.

Yes - Go is full of concepts like 'aji' (lit. "taste"), thickness, influence, good and bad shape which are features that can only really be evaluated in terms of actual points dozens of moves later.

I think Go is particularly difficult for AI because you need fuzzy pattern matching and precise reading out of positions (life and death problems). as well as the judgement to know when to use which.

According to Google - $14,281.50

The point isn't that those 50 Bitcoins are worth $14k, it's that he owns up to a million of them, and nobody is sure who he is or whether he still had control of those coins. This seems to prove that he does, unless blockchain.info is wrong.

> it's that he owns up to a million of them

We have no evidence that that is true, however it is widely speculated and believed to be so.

The speculation for that particular number is trivially falsified: It's based on assumption that all unmoved coins in the first year were mined by the system's creator (no justification is provided for this assumption).

And it is false, many other people mined during that time and lost keys (myself included).

I play Go a lot, and chess occasionally.

I think it's about mindset not skillset - games like these are about solving local problems ('tactics') to achieve a greater aim ('strategy'); people who are attracted to them are generally people who like the sort of problem solving that comes up in programming, hence the cross-over.

Your question, however was whether or not the skills translate - I don't think that solving daily chess problems or tsumego will do as much for your programming than solving programming puzzles (e.g. codewars), but the discipline of thinking through all possible paths ('reading') definitely helps.

neil, are you on OGS?

Yeah :-)

I got some very interesting results from feeding fractal images into a program like this a few years back - unfortunately, I don't have the resulting sounds, but you pick less busy images with filaments, and adjust the contrast - the result is very organic. Must have a go with this ...