User talk:Tobias Bergemann

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[edit] The Humungous Image Tagging Project

Hi. You've helped with the Wikipedia:WikiProject Wiki Syntax, so I thought it worth alerting you to the latest and greatest of Wikipedia fixing project, User:Yann/Untagged Images, which is seeking to put copyright tags on all of the untagged images. There are probably, oh, thirty thousand or so to do (he said, reaching into the air for a large figure). But hey: they're images ... you'll get to see lots of random pretty pictures. That must be better than looking for at at and the the, non? You know you'll love it. best wishes --Tagishsimon (talk)

[edit] Article Licensing

Hi, I've started a drive to get users to multi-license all of their contributions that they've made to either (1) all U.S. state, county, and city articles or (2) all articles, using the Creative Commons Attribution-Share Alike (CC-by-sa) v1.0 and v2.0 Licenses or into the public domain if they prefer. The CC-by-sa license is a true free documentation license that is similar to Wikipedia's license, the GFDL, but it allows other projects, such as WikiTravel, to use our articles. Since you are among the top 2000 Wikipedians by edits, I was wondering if you would be willing to multi-license all of your contributions or at minimum those on the geographic articles. Over 90% of people asked have agreed. For More Information:

To allow us to track those users who muli-license their contributions, many users copy and paste the "{{DualLicenseWithCC-BySA-Dual}}" template into their user page, but there are other options at Template messages/User namespace. The following examples could also copied and pasted into your user page:

Option 1
I agree to [[Wikipedia:Multi-licensing|multi-license]] all my contributions, with the exception of my user pages, as described below:
{{DualLicenseWithCC-BySA-Dual}}

OR

Option 2
I agree to [[Wikipedia:Multi-licensing|multi-license]] all my contributions to any [[U.S. state]], county, or city article as described below:
{{DualLicenseWithCC-BySA-Dual}}

Or if you wanted to place your work into the public domain, you could replace "{{DualLicenseWithCC-BySA-Dual}}" with "{{MultiLicensePD}}". If you only prefer using the GFDL, I would like to know that too. Please let me know what you think at my talk page. It's important to know either way so no one keeps asking. -- Ram-Man (comment| talk)

[edit] Bundesland-level categories

Hello! I see you are listed in Category:Wikipedians in Germany. I have made subcategories for each Bundesland in case you would like to add yourself to the appropriate one. See Category:Wikipedians in Germany for a list of the subcategories (they use the English names, the same as their Wikipedia articles). --Angr (tɔk) 15:55, 15 January 2006 (UTC)

[edit] forth and scheme

I see you are interested in both Forth and Scheme. These are my two favorite languages, and I feel they have much in common, both having minimalist philosophies and being highly extensible. What do you think? How did you get interested in them? (you can reply here, I'll watchlist you) Ideogram 10:36, 15 June 2006 (UTC)

Speaking as an engineer (well, I am a physicist really, but I work as a software developer), I generally find an economical use of resources and concepts attractive. I would not call Forth or Scheme my favorite languages, however. I like them because they encourage a bottom-up/incremental approach to software development (which in my experience leads to really nice solutions) and because they encourage the development of domain-specific languages. However, the one resource that I now value most highly is developer time, i.e. the time that I myself have to invest to solve a given problem. The one drawback of minimalist languages (I would include Lua into this category) I see is that while I can extend them in all possible directions I often have to do a lot of things myself that I do not have to with other languages.
Both Forth and Scheme suffer from highly fragmented user communities ("If you have seen one Forth, well, then you have seen one Forth."), both with dozens of mostly but not quite standard-conforming implementations an few portable libraries. I think this a result of their respective minimalist philosophies.
I learned Forth to see how close one could get "to the metal" while retaining the possibility to use high-level concepts, and I learned Scheme to understand continuations, and because it is used in the book Structure and Interpretation of Computer Programs. I learned them years before I considered working as a software developer. During that time I also toyed around with Prolog and Common Lisp. At work, we use a mixture of C++ and Python.
I have not had the chance to use Forth or Scheme in a commercial setting yet, and I wonder how well they scale to teams with more then a dozen developers.
That said, I still like to use Scheme if I do not know what I am doing, i.e. if I am trying out things, toying with ideas etc. — Tobias Bergemann 11:06, 15 June 2006 (UTC)
I think you make valid points regarding the disadvantages of minimalist philosophies. I was always turned off by the philosophy of Perl but when I actually used it I was amazed at how quickly I could produce something. It just goes to show no language is perfect.
I actually feel continuation-passing is a better foundation for programming than function calls. Carl Hewitt in his Actor paradigm showed that continuation-passing can represent all control structures, and it generalizes to parallel distributed systems better than synchronous function calls. The requirement to optimize tail-recursion is an ugly hack in the Scheme specification that would not be necessary in a continuation-passing style.
BTW I am working heavily on programming language and I would love to have your input there if you are interested. I even copied your references on typing for use there. Ideogram 11:38, 15 June 2006 (UTC)
On a syntactic level, explicit continuation-passing can get annoying if you have to write down all intermediate continuations. This may be strictly a language issue, and may well vanish with a syntax that is better adjusted to continuation-passing (for example, the Io language used in Raphael Finkel's book Advanced Programming Language Design; this is not the same language as Io). However, there are certainly situations where continuation-passing can actually improve the clarity of a program, e.g. when you are passing around explicit error continuations or are simulating Prolog-style constraint programming. (These uses can often be simulated with exception handling as they only use single-shot upward-only continuations.)
On a semantic level, I find it difficult to reason about the performance of a program written with explicit continuation-passing. It all depends on the concrete representation of the continuations, I guess. Modern Scheme and ML compilers work hard to remove unnecessary continuations, e.g. using Amr Sabry's Administrative Normal Form internally.
I probably would prefer to work with a rich language that supported exception handling, co-routines, cooperative multithreading, futures etc. out of the box than work with "naked" continuation-passing.
My knowledge about parallel distributed systems is too limited to form an opinion about the advantages and disadvantes of continuation-passing. Do you mean distributed as in geographically distributed networked systems? Does your definition of parallel include mutable shared state?
Shared memory parallelism is one model but it does not map well to distributed systems, which, indeed, may be geographically distributed and therefore have high latency. The actor paradigm is based on message-passing and has no globally shared state. Continuations can naturally be viewed as a form of message-passing.
The high latency and possible communication failures in geographically distributed systems favor asynchronous message-passing over synchronous function calls which may block for arbitrarily long periods of time. This solution has been discovered over and over every time large geographically distributed systems have been built.
Note that with increasing clock rates and shrinking feature size the same issues with geographically distributed systems appear for signals that have to travel across a large CPU chip. Current practice is moving to multicore chips for this reason; they generally have a shared memory architecture but this will become increasingly difficult as cores and caches multiply and cache coherence becomes an issue. See the Cell chip architecture for instance which does away with cache entirely.
As for the ongoing work on the page programming language, I am not sure I can be of much help. This is a really big topic, given the rich history and the sheer number of programming languages. — Tobias Bergemann 12:54, 15 June 2006 (UTC)
No one "knows it all" regarding the subject. What makes Wikipedia great is we can each contribute part of the knowledge. We only need a general overview in any case; it is intended to be an introduction to a reader who doesn't even know what a programming language is. You have already contributed by giving me two references on types that I was able to use; our greatest need right now is for more references on already written material. Come on, it'll be fun! Ideogram 13:24, 15 June 2006 (UTC)

Thank you for your heavy work on forth. It is greatly appreciated. Ideogram 15:33, 20 June 2006 (UTC)

[edit] The "programming language" article suffix

I read your comments on the language naming conventions talk page about the questionable "programming language" article suffix, and i thought you might be interested to know that several editors (including me) are trying to get the policy fixed. --Piet Delport 15:44, 5 August 2006 (UTC)

[edit] cofinal

I was a bit puzzled by the definition cofinal set of subsets on the Cofinal (mathematics) page. I've put a question on the discussion page and wondered if you could have a look at it? Francis Davey 09:44, 9 August 2006 (UTC)

[edit] Hello!

Just a word of greetings :-) --HappyCamper 09:34, 14 August 2006 (UTC)

[edit] "feel free to revert if you prefer the previous version"

I thought your changes to Prime number theorem make the article look much neater, actually. It's much better than two header rows. CRGreathouse (talk | contribs) 18:29, 15 August 2006 (UTC)

That is reassuring to hear. It's just that in light of the current debates on Wikipedia talk:Citing sources and Wikipedia talk:Citation templates I try to be really careful with this kind of edits. — Tobias Bergemann 07:19, 16 August 2006 (UTC)

[edit] RV?

You did the following: "Removed rant ("This is not a forum for general discussion about the article's subject."))" Ok. So, what is the proper venue for discussion? Respond back at my talk page, thanks. C++ Template 14:57, 2 March 2007 (UTC)

[edit] Sighting

It was a pleasure to spot a genuine WikiGnome in action. Thank you for your help! Geometry guy 19:26, 3 April 2007 (UTC)

[edit] A moron.

Sorry about that, I won't be calling people "morons" anymore and won't bite them either. Just that I am always getting very touchy about that subject, because it seems to me as an inconceivable inequity towards Albinoni, on a hand, and act of foolishness from those who still believe that's one of the finest Baroque pieces, or those who've heard it's a lie but still are stubborn. All in all, it was just some sick publicity for a piece that would have never gained attention otherwise, had it been not attributed to Albinoni and claimed as a disappeared piece recovered! All these, on behalf of money. Impy4ever 12:23, 1 June 2007 (UTC)

Thanks. (I can relate to what you write. Still, the world is harsh enough without people calling each other names.) — Tobias Bergemann 12:28, 1 June 2007 (UTC)

[edit] simpletons

While I can understand the concept of not telling people how stupid they are in an overt and offensive manner, I find myself unable to restrain myself when a fool refuses to think before taking action. 74.13.39.27 21:44, 19 June 2007 (UTC)

[edit] WikiProject Germany Invitation

Hello, Tobias Bergemann! I'd like to call your attention to the WikiProject Germany and the German-speaking Wikipedians' notice board. I hope their links, sub-projects and discussions are interesting and even helpful to you. If not, I hope that new ones will be.

--Zeitgespenst (talk) 20:21, 10 March 2008 (UTC)

[edit] WikiProject Germany Invitation

Hello, Tobias Bergemann! I'd like to call your attention to the WikiProject Germany and the German-speaking Wikipedians' notice board. I hope their links, sub-projects and discussions are interesting and even helpful to you. If not, I hope that new ones will be.

--Zeitgespenst (talk) 23:05, 10 March 2008 (UTC)

[edit] Hello

I've seen your important contributions for the article Exact trigonometric constants. I'm looking for the general (non-iterative) non-trigonometric expression for the exact trigonometric constants of the form: \begin{align}\cos \frac{\pi}{2^n}\end{align}, when n is natural (and is not given in advance). Do you know of any such general (non-iterative) non-trigonometric expression? (note that any exponential-expression-over-the-imaginaries is also excluded since it's trivially equivalent to a real-trigonometric expression).

  • Let me explain: if we choose n=1 then the term \begin{align}\cos \frac{\pi}{2^n}\end{align} becomes "0", which is a simple (non-trigonometric) constant. If we choose n=2 then the term \begin{align}\cos \frac{\pi}{2^n}\end{align} becomes \begin{align}\frac{1}{\sqrt{2}}\end{align}, which is again a non-trigonometric expression. etc. etc. Generally, for every natural n, the term \begin{align}\cos \frac{\pi}{2^n}\end{align} becomes a non-trigonometric expression. However, when n is not given in advance, then the very expression \begin{align}\cos \frac{\pi}{2^n}\end{align} per se - is a trigonometric expression. I'm looking for the general (non-iterative) non-trigonometric expression equivalent to \begin{align}\cos \frac{\pi}{2^n}\end{align}, when n is not given in advance. If not for the cosine - then for the sine or the tangent or the cotangent.

Eliko (talk) 07:38, 31 March 2008 (UTC)

I am not sure what you are asking for. Using the usual addition theorem I get the following:
\cos \alpha = cos \left( 2 \cdot \frac{\alpha}{2} \right) = 2 \left(\cos \frac{\alpha}{2}\right)^2 - 1
And then:
\cos \frac{\alpha}{2} = \sqrt{\frac{1}{2} \left( 1 + \cos \alpha \right)}
(In the region where cos(α / 2) is non-negative). From this we find
\cos \frac{\pi}{2^{n+1}} = \sqrt{\frac{1}{2} \left( 1 + \cos \frac{\pi}{2^n} \right)}
So I take it you want a closed formula for this square-root? — Tobias Bergemann (talk) 09:25, 31 March 2008 (UTC)
What you give here is an iterative formula, using the trigonometric term "cos". I'm looking for the general (non-iterative) formula, using no trigonometric terms. Eliko (talk) 09:28, 31 March 2008 (UTC)
Hm, I don't now of such a general formula. Let's see:
\begin{array}{lcc} \cos \frac{\pi}{2^n} & = & \sqrt\frac{p_n}{q_n} \\ \cos \frac{\pi}{2^{n+1}} & = & \sqrt \frac{1 + \sqrt{p_n/q_n}} 2 \\ & = & \sqrt \frac{\sqrt{q_n} + \sqrt{p_n}}{2 \sqrt{q_n}} \\ & = & \sqrt\frac{p_{n+1}}{q_{n+1}} \end{array}
So we get q_{n+1} = 2 \sqrt{q_n} and p_{n+1} = \sqrt{q_n} + \sqrt{p_n}. We also have q1 = 1 and p1 = 0. So we get
q_1, q_2, q_3, q_4, q_5, \dots = 1, 2, 2 \sqrt2, 2 \sqrt{2 \sqrt 2}, 2 \sqrt{2 \sqrt{2 \sqrt 2}}\dots
and
p_1, p_2, p_3, p_4, p_5\dots = 0, 1, \sqrt 2 + 1, \sqrt{2 \sqrt 2} + \sqrt{\sqrt 2 + 1}, \sqrt{2 \sqrt{2 \sqrt 2} + \sqrt{\sqrt{2 \sqrt 2} + \sqrt{\sqrt 2 + 1}}}, \dots
I don't see how this can be rewritten in a more closed, non-iterative form. — Tobias Bergemann (talk) 10:14, 31 March 2008 (UTC)

(De-indent.) I see that you have asked the same question on several other user talk pages. It may have been preferable if you had asked your question at the mathematics reference desk. — Tobias Bergemann (talk) 10:31, 31 March 2008 (UTC)

Thank you.
By the way: Are you sure \begin{align}\cos \frac{\pi}{2^n}\end{align} must be of the form \begin{align}\sqrt\frac{p_n}{q_n} \end{align}?
Eliko (talk) 10:36, 31 March 2008 (UTC)
Trivially yes, as I did not specify pn and qn any further in my ansatz. (Every non-negative real number can be written in a myriad ways as the square root of the quotient of two other non-negative real numbers.) — Tobias Bergemann (talk) 11:49, 31 March 2008 (UTC)
I've meant: are you sure there are two non-trigonometric functions, P and Q, over the natural numbers, such that \begin{align}\cos \frac{\pi}{2^n}\end{align} is of the form \begin{align}\sqrt\frac{P(n)}{Q(n)} \end{align}? Eliko (talk) 12:22, 31 March 2008 (UTC)

[edit] Your Edits to Zero sharp

I love it. Thank you. I loathed the way the lede paragraph read previously but never took the time to fix it. Zero sharp (talk) 18:28, 10 April 2008 (UTC)