Tagged: Unity

The maths of the spirograph… with the drawings


Well, I sat down and thought this was going to be easy, but it has taken me three hours to work the maths of a smaller inner wheel rolling around inside a large outer wheel: mainly because for the first two of those I neglected the basic insight that the inner wheel rolls in the opposite direction to its direction of travel (think of it this way – as a car wheel moves forward the point at the top of the wheel moves backwards - relative to the centre of the wheel).

And instead of using MetaPost I resorted to a spread sheet – though I might do a MetaPost drawing still.

Anyway – assume you have a big wheel of unit radius and a small wheel inside it of radius \frac{1}{R} .

At any given time the centre of this small wheel will be at cartesian co-ordinates (assuming the big wheel is centred on (0,0):

(cos(\theta)(1 -\frac{1}{R}) , sin(\theta)(1 -\frac{1}{R})) (1)

where \theta is the angle of rotation of the small wheel relative to the centre of the big wheel.

But if the small wheel has moved through angle \theta relative to the centre of the big wheel, then it will have itself rotated through the angle R\theta - in the opposite direction to its rotation around the centre of the big wheel.

This means a fixed point on the surface of the small wheel will now be, compared to the centre of the smaller circle, at cartesian co-ordinates:

(\frac{cos(\theta - R\theta)}{R}, \frac{sin(\theta - R\theta)}{R}) (2)

And we add (1) and (2) together to get the co-ordinates relative to the origin (ie the centre of the bigger circle).

Looking at the above it should be relatively obvious that if R is an integer then the pattern will represent R cusps – and not much less obvious is the fact that if \frac{1}{R} can be expressed as a rational number then the pattern will repeat. But if \frac{1}{R} cannot be expressed as a rational then it turns out there are a countably infinite number i.e., \aleph_0 , number of cusps. In a way this is just a graphical way of representing an irrational number – it is a number that cannot be made to divide up unity (the circle) into equal proportions.

So here are the pretty pictures:

Let R = 2 and we have a degenerate case -

2 cusp figure from 'spirograph'Then the 3 cusps of the ‘deltoid’:

Three cusped deltoidThe four cusped astroid:

Four cusped astroidAnd, here is the spreadsheet:
spirograph spreadsheet

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The more people use “Unity” the less they like it


UnityAdmittedly this is a “focus group of one” but returning home from some weeks away, the other half says “you know the way my computer works now?” Me: “oh, Unity?” Her: “Yes. Well, it’s ****. Can you get rid of it?” Me: “I thought you said you liked it?” Her: “That was before I had to do some work.”

But it seems Canonical still are not prepared to admit their mistake.

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“bye bye ubuntu you suck now” – so how can I switch to Mint?


Linux Mint 10 Julia

Image by pexatar via Flickr

The first half of this blog’s title was a search string that took someone here. I tend to agree.

So is there a way to seamlessly switch to Mint? I don’t have a separate /home partition so the route that most people seem to recommend is blocked to me.

I think there used to be scripts but I cannot find any up to date ones, so can anyone help?

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Ubuntu annoyances and some fixes


Ubuntu Login

Image via Wikipedia

OK, after a week of 11.10 I thought I’d list some of the problems and what to do about them. It’s not happy reading – I think it is fair to say Canonical have dropped the ball on this one.

  • Unity – this is the joke Ubuntu think we should be using as a desktop interface. It’s rubbish, just use Gnome:sudo aptitude install gnome-panel and then select Gnome when you login (click on that wheel thing beside your name on the login dialog).
  • Evolution – this is nearly as bad as the Unity decision, but Ubuntu have banjaxed Evolution and I can see no obvious fix – I am using Thunderbird instead, but it is also broken (a bug is in the Ubuntu bugzilla but no fix is apparent) and complains about the Ubuntu One address book. You just have to ignore the errors and hope somebody gets around to fixing it. Better yet, gets round to fixing the distro so that Evolution works on it.
  • Skype – this too is broken by 11.10. But it can be fixed. sudo apt-get install libxss1:i386 && sudo apt-get install libqt4-core:i386 && sudo apt-get install libqt4-gui:i386 && sudo apt-get install libdbus-1-3:i386 (NB: use apt-get as aptitude seems to have some issues with this.) Be careful, though, as installing these libraries might cause you some other issues – have not for me, but they seem to drive a lot of other consequential changes.
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Upgrading to Ubuntu 11.10 and getting rid of “Unity”


I have now upgraded the laptop on which this is being typed to Ubuntu 11.10 and there were a few problems and issues:

  • The upgrade killed the wireless connection and then failed (late on) because it could not download the Adobe Flash installer – but it was late enough in the upgrade process to allow me to boot into 11.10 and then complete anything that needed doing with sudo aptitude dist-upgrade
  • You are forced to use the abomination that is “Unity” – still looks and feels like something a five-year-old would have designed. It’s a disgusting waste of time. You can probably tell I don’t like it. So get rid of it with sudo aptitude install gnome-panel
  • Before I got to that point it tried to boot into something called “Ubuntu 3D” – which is something to do with the ludicrous Unity. It failed (this is running dual head) telling me I was exceeding the 3D capacity of my video card (at least that’s what I think it was trying to tell me) and then went into “Ubuntu 2D” – which worked reasonably well.

The issue I had with the desktop background disappearing when going dual head has gone, though Gnome panel handled the dual head properly while Unity 2D still had “issues”.

But, overall, it seems to have gone well enough. At least once I got rid of Unity. Have I told I don’t like it?

Is Ubuntu in decline?


Official Ubuntu circle with wordmark. Replace ...

Image via Wikipedia

The conclusion in Linux Format magazine is that, yes, it is. It’s still the most popular distro, but the gap has closed with Mint (which offers Ubuntu-Done-Right I suppose) and Fedora.

Five years ago I was a Fedora user but then they issued a release that oopsed on booting, so I had no choice but to use Ubuntu and until the release of the awful “Unity” desktop have never thought of using anything else.

I guess I would just go straight to Debian if starting from scratch these days.

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Further thoughts on “Natty Narwhal”


Official Ubuntu circle with wordmark. Replace ...

Image via Wikipedia

There are six computers in the house running Ubuntu (two are laptops) so there still a few more upgrades to go, but the process is underway (caching makes subsequent upgrades much faster).

The good news is that the upgrade to one machine – usually run as a headless email/web/squid server fixed a few configuration problems there, so not everything is bad.

The most annoying things remain (in no particular order) with Unity:

1. Lost the applets from the desktop. Knowing the temperature outside was occasionally useful and knowing the CPU temperature could sometimes be a pointer to a runaway process on the box.

2. Not being able to switch desktops with a single mouse click.

3. Not being able to see what applications I am running.

4. Not being to switch applications  with a single mouse click.

Maybe all these are fixable?

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Ubuntu 11.04: first impressions


Ubuntu 11.04 Natty Narwhal

Image by pexatar via Flickr

Sad to say these are that I don’t care for it very much.

The “Unity” interface is just ugly and it reminds me of the way Microsoft shifted their Office menus so that, three years on from first using it I still don’t know where familiar and useful things are.

Why does it have Ubuntu One and Ubuntu Software Centre icons in pride of place? I have never made much use of either and frankly it smacks of somebody forcing their wares on me – the sort of thing that is likely to go down like a cup of cold sick in the Linux community.

Maybe there are lots of other good things here, but I cannot find them thanks to Unity. I cannot even find my bookmarks in Firefox the way that has been messed with.

So, not good so far.

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