Mixing boost versions –as-needed

Some linux distributions defaulted to use the –as-needed linker flag for a while. Ubuntu tried it in natty, but then reverted. Now with oneiric, it really is enabled by default.

I ran into this when one of my packages wouldn’t compile on oneiric. I always got linker errors with boost::filesystem and boost::system. Between natty and oneiric, the default version of the packaged libboost changed from 1.42 to 1.46, thus switching from filesystem v2 to v3. Obviously my first thought was that it must have to do with that. Also libwt which I use in the project had the same error in a previous version. So, I reduced my app until I was sure that couldn’t be the cause here. Also all my other packages didn’t have any problems with the transition to filesystem v3 apart from the regular changes for adapting to the new interfaces. But for these changes the compiler helps.

The project in question is organised more or less like that:

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Best names for algorithms

I’ve worked in Baar for two months now and I go to work by train. It takes a while longer than to Schwyz as before, but I don’t have to switch trains or busses. That means it’s good for reading. Currently I read “Artificial Intelligence: A Modern Approach” which is accompanying an online curse (ai-class.com from Stanford) that I currently attend. Today I was reading in the chapter about neuronal networks. There it describes an algorithm called “optimal brain damage“. It tries to find an optimal topology for the NN by randomly cutting connections from an initially fully connected NN.While it describes adequately what the algorithm does, it struck me awkwardly when I first read the name.

What are the best names for algorithms you have come across?

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Schächental GoPro Fotos

Yesterday I waited for the fog to disappear as predicted, but it didn’t happen. So today we went to Unterschächen in Uri where there is very seldom fog. When we arrived, I saw that WinWings were there just ready to dirve to take off. Sure enough they had a place left for me in the bus. The flight was nothing special, but in November every flight is better than sitting in the fog. The calm air was perfect thought to try my new toy. I got the GoPro outdoor camera mainly to take pictures during tandem flights so I can sell them. But now that I have it, why not use it for solo flying and speed flying as well? Here are some pics:

RepRap part 3: Ethernet connection

With the X and Z gears propperly glued, all axes moved. But it didn’t take long for the Z axis gear to break again. The gear that came with the kit was multilayered wood glued together and laser cut. The place where the belt is, is off the axle of the stepper motor. That’s obviously not a good combination. So I ordered an alloy gear from maedler. That came without a hole in the center. I didn’t have anything else then my hand drill available. Well it’s a bit more off center then I had hoped, but nut much worse than the laser cut wooden gears. And still, it works. So, all three axes work now. The ammount by what they move doesn’t seem right, so I’ll have to adjust some parameters still.

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RepRap Part 2 : It moves

It’s been a while since I assembled the Gen7 Electronic board and the extruder. I ordered the extruder together with the steppers from the Netherlands. The hot end v6 is a very nice design compared to the original, where you had to wrap the heating wire around the nozzle yourself. But it’s too big to fit through the hole of my wooden X-Axis sledge from the gffr kit. So, for the moment the extruder is tied to the X-sledge with a clamp.

When I assembled the electronics, I flashed the Teacup firmware onto it but I was never able to connect to it with the reprap host software on the computer. When I connected to it with a serial terminal, I saw a “0” about once a second.

Now after some months I found the time again to make some progress on my RepRap. Also ReplicatorG showed no sign of a successful connection. So I thought to be sure, I would flash the firmware again. But this time I didn’t succeed in doing so, not even with the ICS programmer. Looks like my avr suffered from a corrupted bootloader. That’s a known bug resulting from random operation during power down. Traumflug guided me through the process of flashing the bootloader on IRC. After that, flashing the firmware worked again. Traumflug also told me that neither the reprap host nor ReplicatorG are too well suited for operating with Teacup. He suggested to use printrun instead.

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My first night at a hospital

Last time I spent a night in a hospital was when I was born moren than 34 years ago. I was never looking forward to the next one.

But this weekend our son Levin hit the ground with his head really hard while playing. He cried badly, and the spot on his head that hit got swollen. We immediately went to the hospital with him. As we suspected, the doctors diagnosed a concussion, and wanted to keep him vor supervision for 24 hours. During the night he cried a couple of times, but because the nose was filled in. They woke him every hour to flash into his eyes with a torch. The next day he plays again as if nothing had happened.

So, my first night in hospital was not as bad …