Dave

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Everything posted by Dave

  1. As you might be able to tell, with all the server woes this never happened! With the new version of IPS installed and running smoothly, I will be trying to get HTTPS support enabled tomorrow. I'll be updating once it's enabled.
  2. As you might be aware, websites are increasingly turning towards secure HTTP (HTTPS) in order to increase security and safeguard user privacy. Browsers such as Google Chrome are placing increasingly stringent requirements on non-secure websites, so we have been investigating switching to HTTPS by default. At SFN, we're planning to trial this from next weekend. Since our forum software only supports one protocol or the other, we are planning to switch over to HTTPS next weekend. From your perspective you should see very little difference, asides from a nice green padlock symbol on your browser bar. However it's also possible that, for a short while, you might see some warnings about certificates being insecure, or mixed-content warnings, whilst we complete the transition. We'll post again here to let you know once HTTPS has been enabled.
  3. Just a quick note to say happy holidays from me and all the other staff at SFN -- I sincerely hope you're all having a great break. I'm also going to take the opportunity to replace a failed drive whilst traffic to the site is a bit lower due to the holiday period, so there will be a short amount of downtime tomorrow at around 10:00am GMT (UTC+0).
  4. Sorry for the short notice but wanted to take the opportunity to replace a faulty drive -- unfortunately took a bit longer than expected!
  5. Happy holidays from SFN

    Apologies for the slightly extended downtime this morning, but the server is now back up and running. Do let me know if you see any issues!
  6. Quick LaTeX Tutorial

    This is a short guide to using the new LaTeX system that has been implemented on the boards. First off, for those who don't know what LaTeX is, a short description. LaTeX is, to all intents and purposes, a fully fledged math typesetting system - basically put, you can write math with it. It's a very flexible and hence very advanced piece of software, and the syntax for it is quite complex, but fairly easy to learn for typesetting smaller equations. On scienceforums.net, we've implemented a small LaTeX system to allow you to typeset equations (in other words, cut out all the x^2 stuff and make things easier to read for everyone). The basic principle behind it is this: you have a LaTeX string, and you surround it by [math][/math] tags. I'll come to the syntax of the actual string in a moment. For those who can already use LaTeX (and indeed, those who can't), a few things to note. In the system we've implemented, a tex file is created, surrounding the string you input with a \begin{display} environment so there is no need for $, $, \[ etc. Also note that we've included the standard AMS files for you; if anyone wants any special characters, I'm sure we can probably accommodate your needs. The images are clickable, so you can see the code that was used to make them by clicking. Now that's all out of the way, onto some examples Examples [math]x^2_1[/math] - Indexes (both subscript and superscript) on variables [math]f(x) = \sin(x)[/math] - A simple function. [math]\frac{dy}{dxx} = \frac{1}{1+x^2}[/math] - Example of fractions - you can create small fractions by using \tfrac. [math]\int_{-\infty}^{\infty} e^{-x^2} = \sqrt{\pi}[/math] - A nice integral. [math]\mathcal{F}_{x} [\sin(2\pi k_0 x)](k) = \int_{-\infty}^{\infty} e^{-2\pi ikx} \left( \frac{e^{2\pi ik_{0}x} - e^{-2\pi ik_{0}x}}{2i} \right)\, dx[/math] - a Fourier Transformation, which is rather large. I could go on and on, but I'll go onto explain some of the basic syntax of LaTeX. Syntax Functions & General Syntax Basically put, if you want to write a math equation in LaTeX, you just write it. If you wanted f(x) = 3, then bung that between to math tags and you're done, producing [math]f(x)=3[/math]. Don't worry about extra spaces or carriage returns, because in general LaTeX will ignore them. It does get a little more complex than this, but don't worry about that for now. Remember that any letters you type in will be presumed to be some kind of variable and hence will be italicised. We also have functions to display more complex things like matrices and fractions, and they have the syntax of having a \ before them, usually followed by some kind of argument. For example, \sin will produce the function sin and \frac{num}{denom} will produce a fraction with a specified numerator and denominator. More on these later. Also remember that LaTeX is case sensitive, so \sigma is NOT the same as \Sigma. Subscripts and Superscripts This is perhaps one of the easiest things to do in LaTeX, and one of the most useful. Let's, for the sake of argument, say you wanted to write x2. Then you'd write x^{2}, producing [math]x^2[/math]. Notice that you don't necessarily need the { and } in cases where you only have 1 thing in the index, for example x^2. But it does care if you want to write something like [math]x^{3x+2}[/math]. Subscripts are done similarly, but you use the _ operator instead of ^. If you want both subscript and superscript, then use the syntax x^{2}_{1} - which is equivalent to x_{1}^{2}. Fractions and functions As I've mentioned, fractions are generated by using the function \frac{num}{denom}. For example: [math]\frac{1}{3}[/math] [math]\frac{7}{x^2}[/math] If you want smaller fractions, you can use \tfrac, to produce things like [math]\tfrac{1}{2}[/math] which will fit into a line nicely without having to seperate it. LaTeX has some nice in-built functions like \sin, \cos, etc. I'm not going to write them all down here, but I'll point you to a website at the end of the document that contains them. Likewise, you can write symbols (such as infinity by using \infty) and Greek letters (e.g. \phi, \Sigma, \sigma, etc) Bracketing You can get all your usual brackets just by typing them straight in; for instance, (, |, [, etc. However, sometimes they won't be the right size, especially if you want to write something like (1/2)n. You can get around this by using the \left and \right commands, and then placing your favourite brackets after them. For instance, to write (1/2)n, we have: [math]\left( \frac{1}{2} \right)^{n}[/math] Integrals, Summations and Limits Integrals can be produced by using \int, summations by \sum and limits by \lim. You can put limits on them all in the right places by using the normal subscript/superscript commands. For instance: [math]\int_a^b x^2 \,dx[/math] [math]\lim_{n\to\infty} \frac{1}{n} = 0[/math] [math]\sum_{n=1}^{\infty}\frac{1}{n^2} = \frac{\pi^2}{6}.[/math] Summary There's a lot more things you can do with LaTeX, and I'll try to add to this as time goes by. Have a look at: http://www.maths.tcd.ie/~dwilkins/LaTeXPrimer/'>http://www.maths.tcd...ns/LaTeXPrimer/ - the LaTeX primer http://omega.albany.edu:8008/Symbols.html'>http://omega.albany....08/Symbols.html - some symbols that you might find useful. If you have any questions about the system, send me a PM and I'll try to help Cheers.
  7. So things look like they have improved quite a bit over the last few hours. Looking at our server load averages for the last 12 hours, it's been quite clear that the load has reduced and SFN feels a lot more responsive. We'll see how we can do in relation to the 'bad gateway' issue over the next few days.
  8. Okay all, I have changed another couple of IPB-specific options. Initial observations are encouraging (disk I/O has been reduced considerably), so let's see if this performs any better...
  9. Both Cap'n and I have been looking over this in the last few days. It looks to me like there is some kind of database issue, specifically with the InnoDB format that's now required by the forum software. This seems to be a lot more write-heavy, for some reason, and it's causing PHP processes to hang, which consequently run out and give the bad gateway error. I'm looking into why this is the case. I've tweaked a few more parameters tonight, let me know if you are all getting slowness still.
  10. After a recent update to our forum software, typesetting equations on SFN has changed a little bit. Although we are still using LaTeX, for a variety of reasons, we've elected to shift over from our custom-written LaTeX generator to the excellent MathJax library, which will take your equations from post text and render them in your browser. Much as before, the idea is that in your post, you surround equations with special characters, and MathJax will convert the contained text into an equation for you. There's two types of equation that you can typeset: Inline math is displayed in the flow of a sentence, such as \( y= x^2 \). This example was produced by using the text \( y=x^2 \). Note that we do not support $ signs as most LaTeX users would be familiar with, since this occurs too frequently in text. Display math breaks up a paragraph and can be used for typesetting larger equations such as \[ y = \int f(x) dx. \] The text then picks up afterwards. This example was produced by using the text \[ y = \int f(x) dx \] , which we note is exactly what one would type in a usual LaTeX document. For reference, the old guide is still available and has a number of useful examples for those getting started. Finally, please note that for legacy posts, the old [math] [/math] tags will still continue to work and these will display equations as inline. However it's likely that older posts may look different to the way that they did before.
  11. New Forum Design?

    Just to clarify and allay your concerns on this point: this is not the case at all. (Nor was it Capn's point.) SFN is operating in exactly the same manner today as it did yesterday and for the preceding decade, i.e. entirely independently. We've simply updated our forum software, and Invision is the company that provides the software.
  12. Welcome to the upgraded SFN

    There's now an updated thread in the maths forums that describes some of the changes to the LaTeX rendering.
  13. You can't be Serious

    Just a quick note: if you want a single line break (instead of a paragraph) hit "shift+return" instead of just return. Additionally, for LaTeX, you can use the math BBCode as before, or you can use more standard notation to add display equations, e.g: \[\mathcal{F}(k) = \int_{-\infty}^{\infty} f(x)e^{ikx} dx \] produces \[\mathcal{F}(k) = \int_{-\infty}^{\infty} f(x)e^{ikx} dx \] I'll try to update the LaTeX guide as soon as I get a chance to reflect these updates.
  14. Welcome to the upgraded SFN

    One additional note from me: we no longer use our older LaTeX rendering system in favour of a browser-rendered MathJax, for various technical reasons to do with the way that posts are parsed and stored in this new forum software. The syntax for using our typesetting is exactly the same as before, but you will probably notice some rendering differences, particularly in older posts. Do let us know if there are technical issues on this front!
  15. New Forum Design?

    Just to throw in my two cents as well: this was an update that we really needed to perform, primarily due to security concerns of the older software being outdated (for around 2 years now, in fact). We'll do our best to smooth over any quirks of the updated software.
  16. Malware Warnings

    Dear all, We received notification from Google a few hours ago that some malware had been injected into some of our forum pages, leading to a warning being displayed whenever SFN is listed in Google search results. Both myself and Capn have investigated this issue and have found no evidence of this so far -- it may be the result of an IP.Board vulnerability that we have just patched. Additionally, we have checked servers and done our best to ensure the site is safe. The issue has been bounced back to Google, and hopefully this should be resolved within the next few hours or days. I will post again once we have received an update.
  17. Malware Warnings

    We'll schedule the IPS4 upgrade before the end of the month - our test install ran pretty well, so we can go ahead once we get a free block of time. In terms of the problem above, I am not convinced it's us that caused the redirect. The offending code is not currently present, as far as we can tell, so I would be more inclined to think it was the public wifi.
  18. Hi all, Apologies, once more, for the downtime today (around the last 6-7 hours). Unfortunately, our server hosts experienced a major power outage this afternoon and the server did not automatically restart when the power came back up. Everything should now be back up, but please let me know if you encounter issues. Dave
  19. Malware Warnings

    Hi Dan, thanks for getting in touch - we had spotted this a few weeks ago, but the template cache did not get rebuilt so it has been lingering on a few pages. I have now rebuilt the caches and removed the offending code. It seems that there is some unknown attack vector, we believe inside IP.Board 3, that is allowing this to reoccur, since there are no other server infarctions and no out-of-place or different files from the original IPB installation. We're scheduling an update to IPS4 which should hopefully permanently eliminate this issue, but the update affects quite a bit of the site, so we have to do a little planning first.
  20. Hi all, Apologies for the extended downtime today. It was necessary to do a server upgrade and I choose one of our least busy times -- UK mornings, on Christmas Eve. Unfortunately before I could finish the update I became a bit ill so had to postpone the last parts until later this evening. Everything should be back in order but if not, let me know. Cheers, Dave
  21. Okay I think I tracked this down -- let me know if this is now fixed! Hope you're all having a good Christmas & Boxing Day
  22. Thanks guys - will take a look this morning.
  23. Brief outage

    Apologies if you were caught in the ~20 minute outage that came rather suddenly today. There was an important security update that needed to be applied, and whilst there was a lull in activity I decided to capitalise on it! Please let us know in this thread, or in the Suggestions forum, if you encounter any problems.
  24. Latex Questions

    Thanks for pointing out these issues guys and apologies for the lack of response. Unfortunately, IPB is a bit finicky when it comes to giving our LaTeX plugin non-htmlized text, so presently there's a bunch of hacks that need to be made in order to get it to work. Probably there are some characters missing from the table we use to do a search-and-replace. I think a better long-term solution for math typesetting is probably to utilise MathJax, which does away with the images and with it, a bunch of headaches such as baseline alignment for inline math. However, there is no IPB plugin for this at the moment, so will require me to do a little development in some downtime, which is pretty hard to come by at the moment!
  25. In order to respond to some security advisories, I will take the server offline at around 9am tomorrow (GMT+1) for approximately 1 hour to perform the necessary updates. During this time SFN will be unavailable. I will post here again once the maintenance is complete.