Computer Science

8:20 AM

@d.w. I don't think persistent is the best choice; the word can mean many things, I don't think it even has a unique meaning in CS.

persistent-data-structure is too long (?); how about persistent-ds?

Gilles

@Raphael persistent-data-structure just fits, but not persistent-data-structures

I agree that persistent is bad

Gilles

9:54 AM

I've renamed the tag to persistent-data-structure

there was no wiki

now there's a starter-class wiki

Raphael

10:11 AM

@Gilles I hesitated because we have been preferring the plural forms

I guess "it's just that one character too long" is a valid reason for an exception. :D

Thanks!

I'm no expert, but I don't think one should use "immutable" in this context -- that word is heavily overloaded and often means different things.

Is not the keeping of the history what's crucial here? But maybe @d.w. can help there.

Gilles

@Raphael what else does it mean? For the meaning that I know, it's correct

the point of persistence is that if you have a pointer to a data structure somewhere, that pointer remains valid and points to the same version of the data structure, no matter what happens in other parts of the code

Raphael

The Wikipedia entry seems to allow for data structures that maintain the history internally, i.e. unlike the typica copy-semantics of functional languages.

Anyway, "immutability" is overloaded, esp. so in OOP. Can the structure change in memory, or are you only interested in the same "view" (wrt its methods)?

hb20007

do u guys if i ask a very simple math question here? I only get troll replies in the math chatroom

* do u guys mind

Gilles

@Raphael oh, yes, I guess persistent also covers explicit version requests. Immutability is rather an implementation technique (a very common one) for persistence

@hb20007 if it's math, here isn't really the place

If you get troll replies, flag for a moderator's attention. But don't confuse that with not getting replies at all — nobody is obliged to reply to you.

Raphael

@hb20007 There's Mathematics for pure mathematics questions.

Gilles

10:25 AM

And if it's a question that should be asked on the site, then ask it on the site.

hb20007

it's too simple for the site

Raphael

@hb20007 I don't think that a too simple mathematics question exists for Mathematics.

Anyway, I see no trolling wrt your question in Mathematics Chat. Tip: if you want to be taken seriously, pose a (mathematics) question without any political baggage.

hb20007

the troller guy started the politics.. I just asked my question initially

Raphael

@hb20007 I agree that the guy was not helpful, but clearly this and this messages of yours were what derailed the discussion.

hb20007

alright maybe I shouldn't have said that. I was trying to justify my question

Raphael

10:34 AM

No justification was needed, the guy was unlikely to listen, anyway. *shrug*

Sab ಠ_ಠ

10:58 AM

Hello fellow computer scientists :P

Well, I'm just a first year cs student but well :P

Sawarnik

@Sabಠ_ಠ In addition to math and what?

Sab ಠ_ಠ

I do Physics and Applied maths too

I will do these till second year but my majors are Cs and Math

Sawarnik

Ook.

@Sabಠ_ಠ Are you on Project Euler?

Sab ಠ_ಠ

I am

But I never actually did anthing

I'll tackle the problems during holidays.

The first few were easy but I stopped

Sawarnik

Ok.

Sab ಠ_ಠ

11:09 AM

I don't remember maybe 2-3

lol

I don't even remember my account lol

oh oh I actually solved 5 of them lol

The first 5

Sawarnik

11:26 AM

@Sabಠ_ಠ Oh ok. I solved 15 last to last year, but then lost interest as it got tougher.

Raphael

Oh noes, we have been boarded!

@Sawarnik I don't know if Project Euler is all that useful for CS training. It's certainly nice to get to do some coding and learn some number theory and combinatorics along the way.

Awal Garg

@Raphael Now tell

Sawarnik

@Raphael I don't know. Its just fun :)

Raphael

@Sawarnik That's enough reason to do them.

@AwalGarg What, a story?

Awal Garg

@Raphael No, tell me, what punchline?

Ok, but one doesn't deliver a joke, isn't it?

@Raphael Ah, ok I get it.... No I don't think so. I think I am genius... Funny is so old fashioned..

Sawarnik

11:38 AM

@Raphael Are you being trolled? :D

@Raphael Yup :)

Bye.

Raphael

@AwalGarg I'm not a native speaker, but Wikipedia uses the phrase.

@Sawarnik Probably. I wouldn't know, I've pretty much been immunized by our resident troll.

Awal Garg

anyways, good luck. I like to see people interested in both computers and maths...

specially those, who hate ecma5script and its sisters

bye :) have a nice day

Sawarnik

@Raphael :D

Raphael

@AwalGarg Bye, likewise.

Awal Garg

@Raphael its not to trusted. he must be joking. - and this is not a joke ok...

vzn

3:20 PM

to me, most coding challenges are worthwhile for CS in general.

but of course its just one element.

one needs diversity in ones intellectual diet.

several coding challenges listed in links here

joy of code 2013

Juho

Project Euler is definitely fun, at least most of the problems. I've done about 60

vzn

cool juho do any use algorithmic type ideas

ie non brute force, CS-std algorithms etc...

figure they do... or figure at least one who knows classic algorithms can do better...

Juho

Yes, and you have to. Most of the problems are made so that you can't brute-force them

vzn

exactly. :)

so there ya go R.

competitions can be very effective in motivation etc

they can also push ppl in certain narrow directions at times...

have you newbies heard of Programming Puzzles & Code Golf?

Juho

Their idea was something like that for each problem, there is a way to solve it in under 2 minutes with even a bit out dated hardware

vzn

3:24 PM

yeah if you cant win without some efficient code, thats hardcore CS right there...

Juho

some of the problems I didn't like just because you can't fit the answer into 64 bits

it's annoying to use bignums in languages that don't have a native support :p

vzn

you can use any language though right?

Juho

yeah

vzn

yeah bignums, one of those modern language constructs, like strings etc...

Juho

and it doesn't have really be a "language" either, you can use MATLAB, Mathematica, pen & paper, or whatever you want. You just input the answer, and the system checks it

vzn

3:28 PM

to me these are the CS version of the putnam competition, which is old/esteemed in math circles

William Lowell Putnam Mathematical Competition

The William Lowell Putnam Mathematical Competition, often abbreviated to the Putnam Competition, is an annual mathematics competition for undergraduate college students enrolled at institutions of higher learning in the United States, Canada, and Tel-Aviv University (regardless of the students' nationalities). It awards scholarships with cash prizes ranging from $250 to $2,500 for the top students and $5,000 to $25,000 for the top schools, plus the top ten individual scores get tuition waived at Harvard, and the top 100 individual scores have their names mentioned by rank to leading univers...

think ideally CS competitions should be scaled up to offer prizes/scholarships also

somewhat on this subj ran across this wild story recently

California regulator seeks to shut down ‘learn to code’ bootcamps / venturebeat

terrible!

Raphael

4:10 PM

1

Q: How to prove that problem is not in P

Given some abstract problem how can I prove that this problem is not in P. I mean, what is the method for proving such thesis?

complexity-theory

Isn't this one too broad?

Juho

@Raphael Seems fine to me, given that we have similar questions like the one I linked to

Raphael

I don't think I like the one you link, esp since the answers are basically "it's hard".

The only examples I have in mind that I like are reference questions.

Does this stand a change to become one? My gut feeling is that if it did, we'd have solved P vs NP.

Juho

I'm not really sure. I can only imagine it's definitely not easy (as the answers in the other question state)

Wandering Logic

9:41 PM

1

Q: Your Thoughts on an "Operating Systems" Proposal

The Stack Exchange team is in the final stages of evaluating a subject for a proposed Stack Exchange site. I'd like to get your feedback and thoughts on this proposal: Area 51 Site Proposal — Operating Systems I'm not generally opposed to creating a more-specialized site when it would attract a...

discussion scope

We discussed this briefly on chat a few weeks ago. Now Robert Cartaino is asking us explicitly on meta.

vzn

11:07 PM

hah interesting.

now you guys have lots of chance to chime in with all the opinions...!

we had quite an animated chat about this stuff...

found on google+

20 questions for donald knuth / informit

> To celebrate the publication of the eBooks of The Art of Computer Programming, (TAOCP), we asked several computer scientists, contemporaries, colleagues, and well-wishers to pose one question each to author Donald E. Knuth. Here are his answers.

> As you say, I've come to believe that P = N P, namely that there does exist an integer M and an algorithm that will solve every n-bit problem belonging to the class N P in nM elementary steps.

the questioners list is a real whos who in CS...

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