Daviddoria

RQ decomposition

Hello. I noticed you created a page on the RQ decomposition, replacing the redirect to QR decomposition that used to be there. Given that the QR and RQ decompositions are almost the same, and that the algorithms are very similar, I would think that it's best to collect all the information in one article. Certainly the QR decomposition article is at the moment more complete than the RQ decomposition article. So, why did you decide to make a separate article on RQ decomposition? -- Jitse Niesen (talk) 11:04, 3 October 2008 (UTC)

I just thought that it is nice when you are looking for RQ that you can find an algorithm that will do RQ, not QR. It's fine if we just make a section about RQ in the QR article, is that ok with you?daviddoria (talk) 21:18, 3 October 2008 (UTC)

I thought a bit more about it. The algorithms for RQ are just small modifications of the algorithms for QR (I assume). I think it's best not to have algorithms for both QR and RQ in one article, because they basically repeat each other. On the other hand, I can appreciate your point that not everybody will find it simple to take an algorithm for QR and rewrite it to produce RQ, so perhaps we should also have an algorithm for RQ. Thus, I'm now no longer sure what's best. As far as I am concerned, you can leave the article on RQ decomposition as it is, but can you please add something to that article to explain the strong connection between the QR and RQ decompositions? -- Jitse Niesen (talk) 12:45, 4 October 2008 (UTC)

What you did looks fine to me. By the way, welcome here. Feel free to ask me any questions if you get stuck. -- Jitse Niesen (talk) 12:55, 7 October 2008 (UTC)

Speedy deletion of Irradiance caching

A tag has been placed on Irradiance caching requesting that it be speedily deleted from Wikipedia. This has been done under section A1 of the criteria for speedy deletion, because it is a very short article providing little or no context to the reader. Please see Wikipedia:Stub for our minimum information standards for short articles. Also please note that articles must be on notable subjects and should provide references to reliable sources that verify their content.

If you think that this notice was placed here in error, you may contest the deletion by adding {{hangon}} to the top of the page that has been nominated for deletion (just below the existing speedy deletion or "db" tag), coupled with adding a note on the talk page explaining your position, but be aware that once tagged for speedy deletion, if the page meets the criterion it may be deleted without delay. Please do not remove the speedy deletion tag yourself, but don't hesitate to add information to the page that would render it more in conformance with Wikipedia's policies and guidelines. Lastly, please note that if the page does get deleted, you can contact one of these admins to request that they userfy the page or have a copy emailed to you. Ironholds (talk) 02:23, 14 April 2009 (UTC)

But the stub didn't explain what it is! That's what a no-context deletion is about, when the reader is left stone stumped as to what the dickens the article is about. Is this something about radiation, or what? How does Monte Carlo come into it? I formed a very tentative hypothesis that it might have something to do with computer graphics; is that the case? --Orange Mike | Talk 17:21, 17 April 2009 (UTC)

The full text was as follows, "The irradiance at a point in a scene is generally very similar to neighboring points. We can store these irradiance values when they are calculated at a point. In Monte Carlo ray tracing, when a ray is cast, rather than immediately computing the irradiance, we can first check to see if the value has already been calculated at a nearby point. If it has, then we can interpolate the determine an approximation of the value at the current point. This is known as irradiance interpolation." Aside from the fact that I still have only a vague guess as to the subject of the stub, the use of "we" (or "you") is pretty nearly always a bad idea in an encyclopedia for adult readers. --Orange Mike | Talk 19:51, 22 July 2009 (UTC)

As a matter of fact, I have written technical articles professionally (cover articles for the leading publication in the field, as a matter of fact); and yes, in those articles, the use of the second person was standard practice. This, however, is a reference work, not a users manual or technical journal. The style is different. --Orange Mike | Talk 12:50, 13 August 2009 (UTC)

August 2009

Welcome to Wikipedia. Although everyone is welcome to contribute constructively to the encyclopedia, we would like to remind you not to attack other editors. Please comment on the contributions and not the contributors. Take a look at the welcome page to learn more about contributing to this encyclopedia. Thank you. Hell In A Bucket (talk) 12:06, 13 August 2009 (UTC)

What that seriously attack? I think that guys is attacking the welfare of wikipedia by deleting so many articles!

Maybe you should take the time to read the policies. It might clear up why this was deleted. Start with wp:rs Hell In A Bucket (talk) 12:15, 13 August 2009 (UTC)

I understand why it was deleted, but I don't agree with that policy. You're never going to get people with the technical know-how to follow all of the rules - you should take what they have to offer and wait for someone else to clean it up / adhere to the rules. Like I said before, something > nothing in my mind - I'd rather read a few lines that potentially don't follow all of the guidelines than be stuck with no information at all and no clue where to go from there.

We have several people with the technical know how. The reason we are so successful is because of policies that are standing. If you aren't prepared to accept that then Wikipedia is not the place for you. I'm sorry to put it that bluntly but high standards must be maintained to have credit. Hell In A Bucket (talk) 12:54, 13 August 2009 (UTC)

Speedy deletion nomination of PanelA1

A tag has been placed on PanelA1 requesting that it be speedily deleted from Wikipedia. This has been done under section A7 of the criteria for speedy deletion, because the article appears to be about a person or group of people, but it does not indicate how or why the subject is important or significant: that is, why an article about that subject should be included in an encyclopedia. Under the criteria for speedy deletion, such articles may be deleted at any time. Please see the guidelines for what is generally accepted as notable, as well as our subject-specific notability guideline for biographies. You may also wish to consider using a Wizard to help you create articles – see the Article Wizard.

If you think that this notice was placed here in error, you may contest the deletion by adding {{hangon}} to the top of the page that has been nominated for deletion (just below the existing speedy deletion or "db" tag - if no such tag exists then the page is no longer a speedy delete candidate and adding a hangon tag is unnecessary), coupled with adding a note on the talk page explaining your position, but be aware that once tagged for speedy deletion, if the page meets the criterion, it may be deleted without delay. Please do not remove the speedy deletion tag yourself, but don't hesitate to add information to the page that would render it more in conformance with Wikipedia's policies and guidelines. Lastly, please note that if the page does get deleted, you can contact one of these admins to request that they userfy the page or have a copy emailed to you. ttonyb (talk) 22:34, 1 August 2010 (UTC)

Wiki-Conference NYC (2nd annual)

Our 2nd annual Wiki-Conference NYC has been confirmed for the weekend of August 28-29 at New York University.

There's still plenty of time to join a panel, or to propose a lightning talk or an open space session. Register for the Wiki-Conference here. And sign up here for on-wiki notification. All are invited!
This has been an automated delivery by BrownBot (talk) 15:15, 3 August 2010 (UTC)

Wikipedia Campus Ambassador

Hi David, I responded to your question at Wikipedia_talk:Campus_Ambassadors. Alin (Public Policy) (talk) 20:53, 23 August 2010 (UTC)

Your support

Hello, I see you are an electrical engineer. I am electrical engineer myself and I've proposed a new wikiproject, Electrical Engineering. Here is the link. I would like to ask your support. Please do participate in the discussion. Thank you. Shriram (talk) 15:12, 7 April 2012 (UTC)

Intersecting conics

I think that your problem is that you added instead of subtracting the two matrices. It all works out ok when you combine the different solutions and end up with just the two points of intersection (each counted twice because of the repeated line solution y = 0). Bill Cherowitzo (talk) 20:34, 28 February 2013 (UTC)

The 4 points of intersection give rise to 3 pairs of lines (in general) each pair being a degenerate conic. To find the 4 points you'll need to intersect two of the three pairs. The third pair is redundant.Bill Cherowitzo (talk) 20:55, 28 February 2013 (UTC)

I didn't follow that last comment. From λ = 1 and μ = -1, you get the degenerate conic 0.5 x² - z² = 0, which is the pair of parallel vertical lines $x=\pm {\sqrt {2}}$. All the common points of of the hyperbolas do lie on these lines, but the lines by themselves do not determine the points. With λ = 1 and μ = -2 (the other solution) you get the degenerate conic, y² = 0. Which is the line y = 0 repeated. All the common points also lie on on this degenerate conic. You need both degenerate conics to give you the actual points of intersection, $({\sqrt {2}},0)$ and $(-{\sqrt {2}},0)$ as the intersection of the two degenerate conics. Bill Cherowitzo (talk) 05:06, 1 March 2013 (UTC)

Yes, intersecting any of the degenerate conics with either of the originals will give the same four points of intersection. In fact, any two of the conics in the pencil will meet at exactly these four points (four counted with multiplicity). The issue is, to find these intersection points do you want to work with quadratic equations or linear equations? The reason to even look for the degenerate conics is to replace a possibly messy computation involving quadratics with one that only involves linear equations. Bill Cherowitzo (talk) 18:21, 4 March 2013 (UTC)