Search found 250 matches

by poohat
Fri Oct 17, 2014 1:25 am UTC
Forum: Hardware
Topic: What is the Best Laptop of 2014
Replies: 10
Views: 8264

Re: What is the Best Laptop of 2014

If money is no object then the 15" Macbook Pro retina. Almost every other laptop suffers from some combination of: 1) bad screen (once you have got used to retina, everything else looks terrible) 2) bad touchpad (with most non-apple laptops the touchpads are really bad and using a USB mouse is ...
by poohat
Fri Jan 31, 2014 4:18 pm UTC
Forum: Computer Science
Topic: Machine learning model vs heuristic?
Replies: 5
Views: 6813

Re: Machine learning model vs heuristic?

[..]that helps you predict for future data. Not. The machine learning model classifies your current data. Whether or not it's useful for future data is anyone's guess. ? A statistical model will typically give you explicit predictive distributions. Even for more heuristic ML methods, there are ways...
by poohat
Fri Jan 31, 2014 4:17 pm UTC
Forum: Computer Science
Topic: Machine learning model vs heuristic?
Replies: 5
Views: 6813

Re: Machine learning model vs heuristic?

I was under the impression that a machine learning method would train on known data (say the link of 100 factors to cancer), and comes up with some "model" that helps you predict for future data. I was told that it ends up being more complex than a simple heuristic (ie if height > 5' and ...
by poohat
Thu Jan 30, 2014 1:27 am UTC
Forum: Computer Science
Topic: Machine learning model vs heuristic?
Replies: 5
Views: 6813

Re: Machine learning model vs heuristic?

The question doesnt make any sense. What do you think a "machine learning model" is?
by poohat
Tue Jul 16, 2013 6:48 pm UTC
Forum: Computer Science
Topic: Building a foundation for CS/machine learning
Replies: 4
Views: 5775

Re: Building a foundation for CS/machine learning

Machine learning is basically just applied statistics, and statistics is built on calculus. Probability density functions are defined as derivatives of distribution functions. Almost the entirety of Bayesian inference (which is the direction that modern machine learning has moved in) comes down to e...
by poohat
Fri Nov 16, 2012 5:20 am UTC
Forum: Mathematics
Topic: Limit of a Changing Probability Distribution
Replies: 22
Views: 4853

Re: Limit of a Changing Probability Distribution

The procedure you describe is known as a Polya Urn process, and has been well studied. It also has applications within the field of nonparametric Bayesian statistics (as a Chinese Restaurant process)

http://en.wikipedia.org/wiki/Polya_urn_model
by poohat
Sun Aug 19, 2012 3:56 am UTC
Forum: Coding
Topic: give me a small project!
Replies: 16
Views: 5583

Re: give me a small project!

Write a program that connects to your facebook account, downloads your friends list, and all your friends friends lists, and displays the result as a social network graph showing who is friends with who Might take longer than 8 hours if youve never wrote a program that can connect to a website befor...
by poohat
Mon May 07, 2012 5:13 am UTC
Forum: Coding
Topic: Getting into coding with a PhD in math
Replies: 20
Views: 9990

Re: Getting into coding with a PhD in math

[*]One thing I've been wondering about is jobs where math, rather than coding, is the focus, but which involve some coding. I've heard that some jobs in finance and "big data" may be along these lines. I'm interested in the coding side of things, but a job like this may be a good way to t...
by poohat
Mon May 07, 2012 4:55 am UTC
Forum: Coding
Topic: Getting into coding with a PhD in math
Replies: 20
Views: 9990

Re: Getting into coding with a PhD in math

I agree with dockaon - as a math PhD from a top university, a 'programmer' or software developer job would be a waste of your specialized talents, and you might as well have not bothered with the PhD. You shouldnt be considering going for an 'entry level programming' job with a PhD from Chicago, unt...
by poohat
Mon Nov 07, 2011 12:07 am UTC
Forum: Mathematics
Topic: Desperately need statistics help
Replies: 5
Views: 1570

Re: Desperately need statistics help

Also the predict() function is what youll probably want for the last part, the syntax being predict(o,x) where ''o' is your fitted model (as in the above post) and 'x' is the new data. Use '?predict' to get more help. R is a great language but the model formulae that it uses for regression/etc can b...
by poohat
Sun Nov 06, 2011 11:57 pm UTC
Forum: Computer Science
Topic: Naive Bayes Classifier Priors
Replies: 1
Views: 1581

Re: Naive Bayes Classifier Priors

I assume it means the prior probability of class membership, i.e P(C_i) (rather than P(C_i|X), which is the condtional probability). In a basic two class problem you have probably been setting P(C_i) = 0.5 for both class, the question is (probably) asking you to use a more informed value. So for exa...
by poohat
Mon Oct 17, 2011 12:38 am UTC
Forum: Coding
Topic: Self-Modifying Code
Replies: 5
Views: 3560

Re: Self-Modifying Code

More powerful languages like Lisp still make regular use of self-modifying code; its the only way that you can do things like (eg) adding new syntax (foreach statements, etc) to the language. You cant really do that in languages like python wtihout a huge amount of hassle though, because unless you ...
by poohat
Mon Aug 29, 2011 3:40 am UTC
Forum: Coding
Topic: CS Student Resume
Replies: 8
Views: 4627

Re: CS Student Resume

If youre genuinely proficient with (eg) Scheme, rather than just having rudimentary knowledge, then I wouldnt leave it off your CV. Mainly because 1) functional programming does occasionally get used in industry so having knowledge of it gives more options, 2) the (admitedly very small) number of jo...
by poohat
Fri Jun 24, 2011 7:40 pm UTC
Forum: Computer Science
Topic: Programming Language Syntax Thoughts?
Replies: 26
Views: 5954

Re: Programming Language Syntax Thoughts?

webbrowsers are the one place where multithreading is really important; compare single-threaded firefox and how the whole browser crashes whenever some site contains broken code, to chromium which runs each tab in a separate thread so that errors in one thread dont crash everything. yeah, if you ign...
by poohat
Wed Jun 22, 2011 10:56 pm UTC
Forum: Computer Science
Topic: Programming Language Syntax Thoughts?
Replies: 26
Views: 5954

Re: Programming Language Syntax Thoughts?

Lisp/Scheme syntax is the best because it lets you do powerful things that you cant do in other languages and thats more important than all the other stuff. Lisp is basically the only language where if you (eg) dont have a foreach statement built into the language then you can literally just add it ...
by poohat
Sat Jun 11, 2011 1:38 pm UTC
Forum: Coding
Topic: Cross language communication over sockets
Replies: 5
Views: 1889

Re: Cross language communication over sockets

just pick whatever data representation format and go for it. JSON is probably best if all your languages have built in parsers/serialization functions for it, otherwise you could use XML if you dont care about the inefficiency. Or something like s-expressions/CSV if youre prepared to write your own ...
by poohat
Sun Jun 05, 2011 11:33 pm UTC
Forum: Coding
Topic: Time Series Languages and Implementation
Replies: 1
Views: 662

Re: Time Series Languages and Implementation

Im not sure what you mean by a "time series language"; you can implement time series algorithms in any language. Im sure there are some python models containing functions for basic time series analysis. Im not sure what you would do with them though, or why/how you want to access the sound...
by poohat
Mon May 09, 2011 12:41 am UTC
Forum: Coding
Topic: Macro Ethics
Replies: 17
Views: 2978

Re: Macro Ethics

Its pointless and makes your code harder to read (both for others, and for yourself when you try to read it again in 6 months time). It also makes the code less portable if you want to recode it in a different language for whatever reason. ochuckles; the powerful Lisp macro system is good for doing ...
by poohat
Mon May 09, 2011 12:30 am UTC
Forum: The Help Desk
Topic: Bandwidth: How much does one person need?
Replies: 13
Views: 7276

Re: Bandwidth: How much does one person need?

Realistically for 90% of people, 10MB will be enough. In most cases, your downloads are limited by the other person's upload speed - how often do you ever see 1MB+/s downloads regardless of your connection speed, unless youre (eg) downloading from microsoft.com or whatever? More than 2MB/s is just a...
by poohat
Fri Apr 29, 2011 1:53 pm UTC
Forum: Computer Science
Topic: Algorithms to Pseudo-code
Replies: 45
Views: 7734

Re: Algorithms to Pseudo-code

This is the wrong question to ask, the right one is "how do I learn to understand the algorithms I'm reading about?". Once you understand how they work, converting them into code usually isnt too hard (but not everything in mathematics can be written down in an algorithm easily, a lot of i...
by poohat
Sun Apr 17, 2011 9:28 pm UTC
Forum: Coding
Topic: Why don't ALL computer programs have customizable controls?
Replies: 25
Views: 3639

Re: Why don't ALL computer programs have customizable contro

... Yeah, but none of this changes the fact it takes half an hour to actually do. Moving a table can also take several days if you have to get health and safety approval before youre allowed to pick it up, but that doesnt mean its time consuming in itself. The customer service point is a fair one I...
by poohat
Sun Apr 17, 2011 1:25 am UTC
Forum: Coding
Topic: Why don't ALL computer programs have customizable controls?
Replies: 25
Views: 3639

Re: Why don't ALL computer programs have customizable contro

Adding redefiniable shortcuts should really take less than 30 minutes of work, you just read the shortcuts from a config file instead of having them hardcoded, and then allow users to modify the file. If adding them would require weeks of effort then the program is probably badly designed in some fu...
by poohat
Sat Apr 09, 2011 1:18 pm UTC
Forum: Coding
Topic: How bad are singletons?
Replies: 24
Views: 3756

Re: How bad are singletons?

Global immutable values are not bad and for types like Strings are often preferred. However the same can not be said for values that mutable or can have there state changed. For example a database connection class is bad to have as a global value because it's internal state will change and it thus ...
by poohat
Fri Apr 08, 2011 1:28 am UTC
Forum: Coding
Topic: How bad are singletons?
Replies: 24
Views: 3756

Re: How bad are singletons?

I dont really get the problem with either global variables or singletons, the hate seems to be coming from an "everything must be OO" perspective, which is a bit silly. If you have (eg) a set of settings that apply throughout your program, defining them globally is easier than passing refe...
by poohat
Fri Apr 01, 2011 10:35 pm UTC
Forum: Computer Science
Topic: Should I help anonimity related projects?
Replies: 13
Views: 2833

Re: could I help anonimity related projects?

Im not sure how Tor encryption specifically works, but end-to-end encryption through SSL can be broken by an ISP playing man-in-the-middle and using spoofed certificates , if they have government cooperation. If Tor doesnt use external certificate authorities for verifying certificates then yes, you...
by poohat
Fri Apr 01, 2011 10:10 pm UTC
Forum: Coding
Topic: Noob Question: How to make an equation look simpler
Replies: 18
Views: 2942

Re: Noob Question: How to make a equation look simpler

Actually if n is stored as a rėal numbėr then you can do

Code: Select all

n*=3+1/n

and that works (since 3n+1 can be rewritten as n(3+1/n)) (this definitely isnt simpler though)

however if n is stored as an integėr then 1/n will return 0 unless you cast it (this is a really dumb thing about python)
by poohat
Fri Apr 01, 2011 10:09 pm UTC
Forum: Coding
Topic: Noob Question: How to make an equation look simpler
Replies: 18
Views: 2942

Re: Noob Question: How to make a equation look simpler

yóur university is silly

I dont think you can condense it further though, unless Python evaluates stuff weirdly and lets you do (n*=3)++ (I doubt it, and good-souled people will recoil from that in horror ilke vāmpires from a crucifix)
by poohat
Fri Apr 01, 2011 10:03 pm UTC
Forum: Coding
Topic: Noob Question: How to make an equation look simpler
Replies: 18
Views: 2942

Re: Noob Question: How to make a equation look simpler

"n /= 2" isnt simpler than "n = n/2", the latter is much easier to understand. Dont confuse "uses less characters" with "simpler". I know when you learn a language its fun to play around with the syntax like that, but in general using too much shorthand is bad...
by poohat
Fri Apr 01, 2011 5:44 am UTC
Forum: Computer Science
Topic: Should I help anonimity related projects?
Replies: 13
Views: 2833

Re: could I help anonimity related projects?

Bear in mind that Tor/etc arent totally secure; if the government really wanted to monitor yòur intérnet usage then they could theoretically force yòur ISP to perform a man-in-the-middle attack and they'd be able to intercept everything. This is more difficult than simple surveillance though, so it ...
by poohat
Thu Mar 24, 2011 11:00 am UTC
Forum: Computer Science
Topic: Computer Science at University
Replies: 18
Views: 3774

Re: Computer Science at University

This has been helping me alot guys, another question which would benefit me massively is what university preferably in the uk would be a good choice for a possible CS Degree? The 'best' ones for general academics and career prospects are Oxbridge/Imperial/UCL/Warwick, depending on your grades, and ...
by poohat
Thu Mar 24, 2011 10:46 am UTC
Forum: Computer Science
Topic: Frontiers in Data Indexing
Replies: 25
Views: 3894

Re: Frontiers in Data Indexing

Databases are generally annotated, to make various activites more complicated than "get bytes X to Y" faster, which does make them bigger, but nothing can possibly make them smaller than an ordered 1 dimensional string comprised of the stored data. So whatever you're thinking, it's defini...
by poohat
Thu Mar 24, 2011 10:18 am UTC
Forum: Computer Science
Topic: Frontiers in Data Indexing
Replies: 25
Views: 3894

Re: Frontiers in Data Indexing

There is some abstract sense in which any possible* data storage system can theoretically be replaced by a 1 dimensional line (the Church-Turing thesis essentially claims that any computer program can be run by a single tape [1D] Turing machine) but that doesnt mean that things are actually stored i...
by poohat
Wed Mar 23, 2011 2:21 pm UTC
Forum: Computer Science
Topic: Bother with Analysis 2 and 3?
Replies: 6
Views: 1450

Re: Bother with Analysis 2 and 3?

ExMathematician wrote:Doesn't look like I am going to do OR as the Masters degree i'd need is based on Business statistics sigh.
What? I find it hard to believe you need a Masters specifically in Business statistics to get onto an OR PhD... Where did you hear this?
by poohat
Wed Mar 23, 2011 6:55 am UTC
Forum: Computer Science
Topic: Throw me potential CS research topics!
Replies: 22
Views: 4884

Re: Throw me potential CS research topics!

Something I always wanted to try was the minimum effort required to cross a hilly plain. The land is defined with some function z(x,y) which should be smooth (Bezier etc) and the objective is to get from x1,y1 to x2,y2 using the least energy. I.e. not a straight line if it takes you over a hill. AF...
by poohat
Wed Mar 23, 2011 6:46 am UTC
Forum: Computer Science
Topic: Frontiers in Data Indexing
Replies: 25
Views: 3894

Re: Frontiers in Data Indexing

So the other night my roommate paid me to read a couple chapters of his CS textbook and take notes on it. In the process, I found out something, that to put it mildly, shocked me. I had no idea that (as far as I can tell) every data storage indexing scheme is one dimensional. [...] I have been thin...
by poohat
Wed Mar 23, 2011 6:06 am UTC
Forum: Computer Science
Topic: Computer Science at University
Replies: 18
Views: 3774

Re: Computer Science at University

It would be difficult, though not impossible, to get a computer programming job without a degree. This varies a lot by employer. Where I work we have a number of keyboard jockeys with CS degrees, and ones who majored in physics, geography or some flavors of the arts. There are a lot of good compani...
by poohat
Wed Mar 23, 2011 5:40 am UTC
Forum: Computer Science
Topic: Bother with Analysis 2 and 3?
Replies: 6
Views: 1450

Re: Bother with Analysis 2 and 3?

Id take the analysis courses. You probably wont do much real analysis during a PhD in computational mathematics (although you might, depends what youre doing), but these sort of classes are good for developing mathematical maturity and if youre struggling then you need all the practice you can get. ...
by poohat
Wed Mar 23, 2011 5:22 am UTC
Forum: Computer Science
Topic: Removing repeated numbers from a very large list.
Replies: 39
Views: 5811

Re: Removing repeated numbers from a very large list.

It was specified that the integers are all 32-bit, so we don't need to worry about exceeding our 2^32 element hash table, but what about only using a small portion of it? This seems pretty wasteful Here is a proposed modification which would increase the time complexity and potentially decrease the...
by poohat
Fri Dec 24, 2010 1:49 am UTC
Forum: Computer Science
Topic: Feels type insecure? (informal discussion of opinions)
Replies: 15
Views: 3116

Re: Feels type insecure? (informal discussion of opinions)

dynamic typing does the work of dealing with types for you "int" instead of "var" ... yeah, there goes my day, better to crash at runtime. You still have to annotate, possibly many times for the same variable with dynamic types. Otherwise it could be (in js) "", undefi...
by poohat
Mon Dec 20, 2010 9:07 am UTC
Forum: Coding
Topic: Similarities between C/C++ and Java
Replies: 24
Views: 5835

Re: Similarities between C/C++ and Java

I don't think the point of a CS course is to educate you on many languages. A course that teaches Java, C++ and Python, as languages, doesn't seem like a good course to me. Really, I think that a CS course should use a language like Java/Python/C# as it's "base" (ie, the language that it ...

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