Author Archives: L. Chamberlain

Album of the Week: Toska – Ode to the Author

I should be going to bed and I have some important emails to read but this album is so good that I want to write some quick words about it.

toska-ode-to-the-author-otta-front-cover

This is the debut EP by the band Toska, which is all of the members of the band Dorje minus Rob Chapman, and is more metally and more proggy. And Ode to the Author is pretty amazing. It’s an instrumental EP from an instrumental band, and this EP is what got me into the more instrumental side of music. It made me realize that, for me, the main barrier to enjoying some music (a lot of metal especially) is the vocals. I’m pretty picky. I don’t like whiny vocals, or intense screaming or growling, or just certain types of singing. I’m not sure what my exact criteria are, but some bands are just ruined for me because I can’t get into their vocalist.

But Toska is not a band with that problem. In fact, I think their style of music really benefits from not having a vocalist, because it allows for a much greater variety in instrumentation. There aren’t really any repeating song-wide riffs, just a sort of theme that ties the whole song together. The first track, Chalk Teeth, (which used to be my second favorite but might be rising to the top) has a really awesome beginning riff that is a really good combination of chuggy low-string stuff and higher pitched dissonance, and just as you begin to take it in, it isn’t played until the very end of the song. It’s these kind of things that make instrumental music interesting for me. (I’m not a classical music guy by any means, but I occasionally try to get into stuff like Rachmaninoff and others, and from my limited experience there’s a lot of this kind of unexpectedness.) There isn’t the structure of intro-verse-chorus-verse-bridge-chorus, so it’s a much more interesting listening experience. Personally, it’s not the kind of music I can easily listen to while trying to work, for instance (although I can’t easily listen to any music and work). Without the vocals, it’s much easier to take in all the intricacies of how the different instruments sound and how they interact with each other. Toska is a three-piece band, so there aren’t a thousand guitar parts or extra instruments, but it doesn’t sound minimal at all. I imagine they would sound pretty similar live to how they sound on the album. (That’s something I really admire.)

This EP also has the prog thing where there are short bridge tracks between songs sometimes. I like this, as an artistic sort of thing, but it’s easy to overdo. There are two of these (Phoneme and Anthropocene), which is probably my upper limit for song to instrumental bridge track ratio. Any more and it would feel like overkill.

My favorite track (now tied with Chalk Teeth, though…) is Infantile. This song really feels like a journey. It starts out with a heavy metal part, goes to a more ambient cleaner part, and then to a more powerchordy part, and just keeps going…. Most of the songs go like this. There’s a heavy part, and then a clean ambient part with a lot of reverb and delay. I’m not a fan of the ambient parts myself, but I know these songs would be less interesting if they were constantly heavy chugging riffs the whole time. Chalk Teeth has a part near the 1:45 mark where it gradually transitions from an ambient part to a heavy part, and it’s awesome. Knowing when to play intensely and when to play softly is something that this band can do very well, and it’s very important, I think.

The other actual songs I haven’t mentioned are Chasm and Illumo, which are both good, but I don’t like them as much as Chalk Teeth and Infantile for some reason. It’s probably the riffs. Chalk Teeth has three awesome riffs, Infantile has a bunch, but the other two don’t really have any that I like that much. I still listen to them, though, and I do think they’re good tracks, but they don’t captivate me as much as Chalk Teeth and Ilumo, which are both amazing.

So, that’s all for now. I’ll try and write about an album every now and then (maybe not as often as the title suggests), but next album is probably going to be something quite different from this one. Or maybe not. Who knows?

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Sieve of Eratosthenes (without iteration) in MATLAB

For my CS class there was an extra credit problem in this week’s problem set where we had to write a sieve of Eratosthenes to find prime numbers up to an input integer. I had written the following for fun a few weeks before:

function [ primes, num ] = sieve( n )
% generate list of prime numbers less than or equal to n

    % start with list of all odd numbers from 3 to n
    primes = 3:2:n;

    % check numbers up to floor of sqrt(n)
    for i = 3:floor(sqrt(n))
        % delete all numbers multiple of that
        primes(mod(primes, i) == 0 & i ~= primes) = [];
    end

    % add the 2 back on
    primes = [2 primes];
    num = length(primes);
end

So this is a pretty standard way of doing it (although it’s way slower than the built-in primes(), which probably uses a much cleverer method that I can’t figure out).

But we haven’t officially been taught iteration in lecture yet, so this problem had a rule of no using for or while loops. It took me a long time of staring at the command window but eventually I came up with this.

function [ primes ] = sieve( limit )

    % first, make a list containing all numbers (potential primes) up to limit
    % don't need to even bother with the even numbers
    % but do remember to put the 2 back on at the end
    primes = 3:2:limit;
    
    % divide each number in primes by every other number (but not itself) and find where
    % that result is a whole number
    evenlyDivide = floor(primes ./ primes') == primes ./ primes' & floor(primes ./ primes') ~= 1;
    
    % anywhere there is a true value means that the number is not prime so
    % get rid of it
    primes(any(evenlyDivide)) = [];
    
    % remembered to add the 2 back on the end because it was taken off at
    % the beginning
    primes = [2 primes];
end

This works because right division (./) in MATLAB works between a 1xN row vector and a Mx1 column vector, where the result is a MxN matrix with every value of the row vector divided by every value of the column vector. This was a little surprising, because my professor said multiple times that you can only right divide vectors and matricies if they are the same size or if one of them is 1×1, which is clearly not the case here.

This method wins for number of lines, but doesn’t win when you run it with a large input like a million:

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Clearly, it’s not the most optimal sieve known to man. Firstly, it doesn’t even take into consideration the sqrt(n) limit on numbers you have to check the primes list with, it just divides the entire list of potential primes by itself, which ends up making massive arrays.

By fiddling around with the solution sieve function they give, I discovered that it uses ones() somehow, but I can’t figure out an alternative method, and this homework is due tomorrow so I can’t really be bothered to try and figure out a method that doesn’t error with inputs greater than 100,000. Hopefully they won’t test any inputs that large. Someday, though, I would like to try and work out a faster and less resource-heavy method for doing this, because I like these kind of problems. (Project Euler is fun too! although it’s hard not to just take the easy way out and brute force some of the problems…)

 

Molecule of the Day #1: Cubane

It’s a cube!

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It’s not very good for the longevity of the single bonds on my molecular model kit, but I did my best to get a semi-decent picture of it:

cubane-model

It has the formula C8H8 and it’s the second simplest prismane (polyhedral hydrocarbons with regular polygonal faces) after prismane itself:

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But it’s boring and looks like a tent so I went with cubane. It was first synthesized in the 60s, but I can’t find any sort of information about its reactivity, besides a really long series of reactions to synthesize it, starting from 2-pentenone.

Cubane belongs to a family of Platonic hydrocarbons, none of which are found in nature due to angle strain, but all of which are nice to look at. Out of the five Platonic solids, only two have been synthesized in hydrocarbon form: cubane and dodecahedrane. Tetrahedrane and octahedrane could hypothetically exist, but have not yet been synthesized due to the extreme angle strain involved.

There’s also octaazacubane, which is eight nitrogen atoms bonded in a cube, with the formula N8:

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which, apparently, has five times the energy density of TNT, despite being a rather stable molecule. It has a cool name, as well, but as far as nomenclature goes it falls short of this one:

Basketane, also synthesized in the 60s. It’s a basket. Two minutes of Google searching found nothing about it, so I’ll assume that not much has been done with it besides synthesizing it, and it’s as good a place as any to end this post.