Computer Science

Evil

00:43

'Similarly, what is "a machine less powerful then a TM"? Any single machine is ... not all that powerful.' What if I pick UTM? With halting Oracle?

Little Alien

08:58

I wonder, how do you make a cartesian power of a list, e.g 'abc'? I tried to start from a dot, which is an empty list. I then should get one-dimensional strings a,b,c when multiply it with possible values. Then, taking second power, I should get strings of len 2: aa, ab, ac, ba, bb, bc, ca, cb, cc and so on.

Theoretically, I map every exsting strings of lenth-1 with abc, I am getting 3 more strings in response. The theoretical problem I see here is that when I try to map an empty, zero-dim strings, I get 0 in response because 0 multiplied by whatever is 0.

How do you program this theoretically?

That is, my cartesian power looks like `(list, pow) =>
range(pow).reduce((acc, _) => cartesian(list, acc).flatten(), [])`. But calling it with (abc, 2) gives me empty array since, I believe, it cannot kick off from 0 dimension -- cartesian(empty, whatever) == empty. How do you work it around?

Little Alien

09:26

Wait, I feel I am getting it.

After first iteration, you get ((), a), ((), b) and ((), c). After second, (((), a), a), (((), a), b), (((), a), c), (((), b), a), and so on.

Now, it is a matter of flattening it.

Little Alien

10:15

But, anyway, cartesian([], whatever) = [].

Little Alien

10:30

Not, it is ([],whatever[1]), ([],whatever[2]), ... = whatever[1], whatever[2], ...

Raphael

11:32

@Evil Yea, well... I wanted to make the OP use precise language in the hope that that would order their thoughts and help them reach an answer on their own. But apparently they insist on using their own language but still expect to be understood.

@LittleAlien Are you asking how to implement the Cartesian product, or are you asking what some operation you want is called?

Bounty!

17:08

-1

Q: Algorithm: How many symbols of occurence k fit into b buckets under condition

I have the following problem to solve: Given a set of buckets $B=\{b_0,\dots b_n\}$ of known size, a constant $k$ < |B| and a set of symbols $S=\{s_0,\dots, s_?\}$ with unknown size. Place a total of $k$ instances of each symbol into some of the buckets of B, whereas there must not be t...

Evil

17:44

I do not get it, bounty? It would be more benefitial if the question was clarified and took hints from the comments...

Unless... There is some quirk preventing bountied question from closure, but in that case there is probably refunding or mod hammer power tool...

roscoe_casita

Yar, I'm going to say that is a great feeling walking into a meeting with thesis /project teacher ... and your prepared. Walk out and they are happy... oh glorious day!

Evil

18:28

@roscoe_casita congratulations, so it was thesis preparation or defending your work?

roscoe_casita

18:40

@Evil just preparation weekly meeting. think status update, but I did my calcs and realized I needed to be writing about a page a day ... so I got my ass in gear.

thesis prep work

Evil

This reminds me my first thesis defense, I was so pumped, hype and the celestial moment of glory, but... my promoteur didn't shared that feeling, overslept and didn't showed up ;)

roscoe_casita

YOUCH

I sat in a presentation recently... the presenter was a guest of a professor... who fell asleep during the presenters presentation

as you can imagine... the presenter was visibly disturbed.

Evil

One page per day? Why?

roscoe_casita

I'm a masters student, I want to get into the phd progrm... I need to distinguish myself. Also, 1 page a day, can be condensing 2 pages to 1 page, etc... just practice writing EVERY day.

this is first term of Thesis, so I wanted to have publishable material before the next year ~

realized I needed to already have 40+ pages done... figured out a reasonable plan of action.

alright, lunch time, keep it easy.

Evil

Could you share the topic?

Raphael

19:52

@roscoe_casita So long as you keep in mind that content is more important than page count.

roscoe_casita

20:08

@Raphael aye, I guess I mostly realized the schedule I needed to stay on to keep up with generating quality content / @Evil hypergraphs, odometers, hilbert spaces and category theory

Evil

I wrote my first one over one night, and wrote the application supporting it. The page count was a new record. It was the new minimum, but quality was excelent, I did supplemented exactly as many pictures as needed, no overbloating

Raphael

@Evil Hehe, been there. The guys I went to for binding wouldn't believe that you could have a bachelor's thesis that short.

Evil

@Raphael I was so hyped that I ordered custom binding and paper, so ommited that part.

roscoe_casita

This is new territory for me

I quit my job of 9 years to go back for masters/phd

Raphael

Wow, kudos.

Evil

20:18

So the knowledge conquers all.

Juho

@Raphael How come I'm purple on the site, but orange (or at least, non-purple) here in the chat o.o

roscoe_casita

Thanks, it was a hell of a change. I'm sitting in the class I'm a teacher for in lab right now ;) (CIS 210)

Evil

@Juho gravatar problem, it appeared some time ago. To me you are orange everywhere.

Juho

oh, okay

Evil

Yeah, I was so confused, let me say purple suited you (or I just got used to)

Juho

20:22

haha, I agree!

Evil

Not everyone was lucky, I cannot get used to Ricks new color...

Raphael

@Juho Still adapting to this change...

heather

hello

Evil

It is like a piktogram theory about double representation that text + picture is perfect identifier, so if nick = name, than change of picture is just like a plastic surgery...

Juho

@Raphael I feel you, it was the same for me when you changed out of that... rat :-D

Evil

20:27

Rat? It wasn't a weasel? Anyway when I saw that police car... Tough...

heather

so, I'm trying to learn about computer science, and complexity theory in particular, what would be some good introductory textbooks?

roscoe_casita

like big O notation?

heather

@roscoe_casita, well, mainly introductory concepts, but yes, I supppose

Juho

@Evil It always looked like a rat to me, but I guess it was something else

Raphael

@Juho Hehe. It was a dog, though.

heather

20:28

And my other question would be what level of math is required to learn general computer science

Raphael

@heather I don't know about complexity theory, but for algorithms I can recommend the Sedgewick series.

heather

@Raphael, okay, thank you, I'll look into those.

Evil

@heather there was a question about that with many awesome answers - taking different paths into account.

Juho

@heather the more math the better, imo. but it depends a bit on what you wanna focus on

roscoe_casita

@heather any solid algorithms book will delve into big O notation, and complexity classes. Lots of discrete math helps

Raphael

20:30

@Juho @Evil: disabilityinkidlit.com/2015/04/04/…

roscoe_casita

I would agree Juho... every branch of mathematics is potentially involved in CS

Raphael

To my knowledge, only one person figured it out in all these years.

heather

@roscoe_casita, I see, okay.

Raphael

@roscoe_casita No, an algorithms book doesn't necessarily do complexity classes.

heather

@Juho, oh, wow. Okay, if I said I'm specifically interested in quantum computing, as well as more overarching problems like the P=NP problem, what types of math should I look into?

Raphael

20:31

Big-Oh is, unfortunately, ubiquituous.

Juho

@Raphael OK, I see now (still looks like a rat to me)

Raphael

@heather I don't think P=NP is particularly overarching... it's a rather specialized question, if very popular.

Juho

@heather in general, combinatorics doesn't hurt

Raphael

@Juho Have you ever seen a live rat? O.o

heather

@Raphael, hmm, I guess I didn't quite realize that. What area of computer science would this fall into then? Complexity theory?

Juho

20:32

@Raphael sure have

Raphael

@heather Discrete mathematics, I guess. And only so much analysis as you need for stochastics.

@heather What now?

@Juho The proportions are very different. In particular, rats don't have much of a neck.

heather

@Raphael, you said P=NP is a rather specialized question, what area of computer science would that problem fall into then?

Evil

@heather well, I do not snoop around... yeah, you have mentioned it somewhere, but I was not Googling either nicks or images ;)

Raphael

@Juho But well, it's a sketch. :D

Can't even remember why I chose it... probably for no particular reason at all.

Juho

@Raphael Exactly :-) It's still an artist's view of whatever it is

Raphael

20:34

@heather Complexity theory.

heather

@Evil, my apologies, I'm not quite sure what you mean.

Evil

@Raphael lol? Of course, the amount of different animals I see everyday is amazing... You haven't?

heather

@Raphael, okay then, that's what I thought =)

Raphael

@Evil I have seen and held a rat, and I have seen and petted dogs. Very dissimilar creatures, mostly.

roscoe_casita

@heather quantum computing is one of the bleeding edges of research in CIS

Evil

20:37

@heather this and this

heather

@roscoe_casita, bleeding edges? Do you mean it is cutting edge research?

Evil

@Raphael I found my cat in the forest and took it... Anyway I saw a fox today

heather

@Evil, thank you for the links!

roscoe_casita

@heather Indeed. You will need to go to the latest journals, papers, seminars, and conferences to get relevant information.

heather

@roscoe_casita, I was pretty lucky in that I got ahold of Nielsen and Chuang's Quantum Computing and Quantum Information, so I'm reading through that.

roscoe_casita

20:42

and then trace their references

and those references ;)

heather

@roscoe_casita, yep =)

Evil

@heather in my opinion you should consider reading various resources about the same topic, there are different styles, examples etc. and also reading more than once will help.

heather

@Evil, thank you, I will keep that in mind as well.

Evil

With at least 24h between reading the same chapter from two books ;)

Raphael

@heather I take it you are a beginning learner?

heather

20:56

@Raphael, yeah, pretty beginner. And it doesn't exactly help that I'm in middle school so I haven't had a lot of the math classes required yet (though I am teaching myself calculus in my spare time).

Raphael

@heather In that case, I'd advise patience. Don't try to learn everything at once -- pick a topic that interests you and start reading anything. Branch out from there, following your "nose". As soon as possible, start doing. As with any skill, doing things is a lot more important than just consuming stuff.

heather

@Raphael, okay. Would doing in this case be doing problems in the textbook, or writing algorithms and trying to improve their efficiency, both, other things...?

Raphael

@heather Both, but I'd focus on the latter for now. And anything that comes to mind. Want to build a quantum computer simulator? Go ahead. Play.

heather

@Raphael, okay, cool! Thanks for all the advice. I'd love to build a quantum computer simulator, not that I have any idea of where to start. =)

Raphael

(Background: textbooks and everything in them are intended to be shortcuts. Their goal is to get you somewhere fast. That doesn't mean that's the best way. If you have the time, take the scenic route.)

@heather Seems like you have a perfect idea: first, find out what constitutes a quantum computer and how it works. ;)

heather

21:02

@Raphael, right, continue reading the books I have, ask questions of course, and then try to start diving in. ;)

Evil

Well, you should consider reading, writing, looking at interactive presentations / visualizations, applications of topic in real world, and repeat from another book, solve excersises and be patient.

And in the end phase, try to teach someone that topic / about that topic

Raphael

21:17

And, of course, don't listen to any advice on the internet because -- as evident here -- you'll get five opinions out of every three people. XD

Evil

21:33

I almost dropped weights... It is true, but it is not the best timming to share that after all advices...

Raphael

Better late than never. ;)

Evil

22:21

@heather and how is the primes code?

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