| --- Log opened Thu Oct 24 00:00:53 2013 | ||
| hansfbaier | poke53281: What background would I need to apply finite element analysis? what parts of num. math, PDEs? What would be a good introduction to FEA? | 01:40 |
|---|---|---|
| poke53281 | The finite element books usually start with the partial differential equation laplace U = rho | 02:16 |
| poke53281 | So, you should understand what this means. | 02:16 |
| poke53281 | Then of course integrals and linear algebra. | 02:16 |
| poke53281 | http://code.google.com/p/dealii/wiki/Literature | 02:17 |
| poke53281 | Here you can find literature | 02:17 |
| poke53281 | including german books. | 02:18 |
| poke53281 | Otherwise I had a very nice online script where I learned how this works. But this over 6 years ago. I can't remember. | 02:18 |
| poke53281 | It's not difficult when you understand the main idea. | 02:20 |
| TW__ | Hi. Working through the ORCONF2013 Workshop ORPSoC on DE0 Nano. Built everything nicely, ran all 3 bare-metal examples on ORPSoC, including UART. Excellent instructions. | 02:20 |
| TW__ | On last step when I downloaded and loaded vmlinux-de0_nano, seems to load nicely but after reset, no response. | 02:21 |
| TW__ | Have I missed something? LEDs just stay steady on and nothing on JTAG or UART. | 02:21 |
| poke53281 | Sorry, can't help you. You have to wait a little bit | 02:22 |
| stekern | TW__: does it work if you try the prebuilt fpga image? | 02:50 |
| TW__ | stekern: I am using the prebuilt image that I downloaded from the link on the workshop page. No apparent functionality after reset. | 03:02 |
| TW__ | I can load the bare-metal images reliably so JTAG/OCD connectivity is working | 03:05 |
| stekern | ok, then that's odd | 03:06 |
| stekern | how are you loading it with openocd? | 03:07 |
| stekern | I assume with the command in the workshop material | 03:09 |
| TW__ | stekern: yes, I am using the OCD command string from the workshop | 03:10 |
| stekern | does it make a difference if you add a resume to the end? | 03:12 |
| TW__ | I just tried again with the downloaded (prebuilt) de0_nano_orconf2013.sof. I have tried reset and resume and changing program counter to 0x100 before resume. | 03:13 |
| TW__ | cannot see any activity on LEDs or UART | 03:13 |
| stekern | and, if you load the baremetal image after you've loded the linux image, does that run then? | 03:13 |
| TW__ | stekern: Yes, I can just do halt, load timerled, and it starts right up. | 03:15 |
| TW__ | load_image seems to wok for vmlinux: 2087404 bytes written at address 0x00000000 2400012 bytes written at address 0x001fe000 downloaded 4487416 bytes in 19.256693s (227.570 KiB/s) | 03:17 |
| TW__ | sizes and addresses make sense | 03:18 |
| stekern | sounds weird | 03:32 |
| stekern | I'll test | 03:32 |
| stekern | but I think everybody at the workshop got linux working | 03:33 |
| stekern | yup, worked here | 03:34 |
| stekern | but actually, it seems like the uart output is missing from the early bootup for some reason... | 03:36 |
| hansfbaier | poke53281: Thanks. | 04:14 |
| hansfbaier | TW__: stekern: I sometimes have it hang, then I do something weird: I kill openOCD, and reprogram the FPGA with ./orpsoc pgm de0_nano. When it is done programming, linux boots on its own in the serial console. Only sometimes needed, usually boots right after gdb loads/continues. | 04:16 |
| hansfbaier | poke53281: I don't know about PDEs yet, will I need additional PDE readings for the Großmann? Integrals and Linear Algebra is fine with me. | 04:19 |
| hansfbaier | still need to refresh my vector analysis though. | 04:19 |
| hansfbaier | poke53281: You probably use FEA a lot, don't you? | 04:19 |
| poke53281 | hansfbaier: I don't know. Maybe not. But then you should start with the Finite difference methods. Finite Elements are more complicated. | 04:22 |
| hansfbaier | poke53281: I also dont know about function theory/functional analysis | 04:22 |
| hansfbaier | is that required? | 04:22 |
| poke53281 | I don't know you what you mean if I know "a lot". I know enough to work with it and to understand the big tutorial of deal. II | 04:23 |
| poke53281 | http://www.dealii.org/8.0.0/doxygen/tutorial/index.html | 04:23 |
| poke53281 | Probably not. You don't need function theory. | 04:24 |
| hansfbaier | the großman explains finite differences, fine | 04:24 |
| poke53281 | Yes. The principles of finite differences is easy. | 04:24 |
| poke53281 | With finite difference you approximate the differential equation. With FEA you approximate the solution. | 04:25 |
| hansfbaier | poke53281: ok thanks. Looks like another huge time sink :) | 04:27 |
| hansfbaier | Thanks for the links | 04:28 |
| poke53281 | Well, the source code could be very small for finite difference. To solve Laplace U = rho takes only 10 lines of code. | 04:29 |
| poke53281 | With finite difference you need a few hundred. | 04:29 |
| poke53281 | The deal.II tutorial is very difficult. It is more or less a summary of all project which were done with this program. | 04:30 |
| poke53281 | They assume already that you know what how finite elements work. | 04:30 |
| poke53281 | So the website is a bad example. | 04:30 |
| poke53281 | Sorry the second sentence should be finite element, not finite difference | 04:32 |
| hansfbaier | poke53281: But the tutorial looks well written. Great resource, though. | 04:35 |
| poke53281 | Yes, but when it comes to the mathematics and why they doing this and this you are lost. Ok, the tutorial I have read 5 years ago. So, there could be some nice additions | 04:36 |
| poke53281 | And again 3 hours wasted for an Heisenbug. The emulated image is crashing randomly. Sometimes with an illegal instruction, sometimes with a wrong memory access. But only if I remove all debug messages and singlestep mode. | 06:33 |
| Powermaniac | Have any of you guys worked at MIT? | 06:55 |
| Powermaniac | Long shot but might as well ask | 06:55 |
| Powermaniac | Friend sort of nudged me in the direction of applying there, just for the hell of it so... | 06:56 |
| olofk_ | I want to pull in the SIGINT fix from _franck_, but my tree has commits made after the pull request. How can I apply the SIGINT fix on top of my tree without having to do a strange merge? There shouldn't be any conflicts | 08:38 |
| olofk_ | Is that cherry-pick? | 08:38 |
| hansfbaier | olofk_: If there are no conflicts cherry-pick should work | 08:48 |
| olofk_ | Can I cherry-pick directly from another repo? | 08:50 |
| hansfbaier | olofk_: If you added it as a tracking branch, it should work. | 08:52 |
| hansfbaier | git remote add a_fancy_name http://an.ur.l | 08:53 |
| olofk_ | ah ok | 08:53 |
| hansfbaier | I then usually also do | 08:54 |
| olofk_ | Is this _the_ way to do it when I want to add a patches that has an older HEAD than my local tree? Or should I do a pull and somehow reparent the extra commit to my head? | 08:55 |
| hansfbaier | If you want, you can also create tracking branches with git branch --track | 08:55 |
| hansfbaier | olofk_: Good question, I'm rather inexperienced in distributed git workflows. | 08:56 |
| hansfbaier | olofk: Probably depends on the desired workflow somehow and/or your taste | 08:56 |
| olofk_ | Because, the branch I'm adding as a tracking branch will probably be a throw-away branch, so I would like to remove it after the cherry-pick | 08:57 |
| hansfbaier | http://git-scm.com/book/en/Distributed-Git-Distributed-Workflows | 08:57 |
| hansfbaier | olofk_: The remote or the tracking branch? | 08:57 |
| hansfbaier | olofk_: You can keep the remote, you don't have to fetch from it. | 08:57 |
| hansfbaier | olofk: This might be interesting: http://git-scm.com/book/en/Distributed-Git-Contributing-to-a-Project | 09:00 |
| hansfbaier | I'll read it to, when I'm less tired. | 09:00 |
| hansfbaier | See you around! | 09:01 |
| hansfbaier | bye | 09:01 |
| olofk_ | I hope I never have to work with John, Josie and Jessica. | 09:04 |
| Powermaniac | ...who? | 09:04 |
| Powermaniac | Don't mind me just being nosy... | 09:05 |
| olofk_ | Powermaniac: It's the three characters from the GIT link that hansfbaier sent me | 09:11 |
| Powermaniac | Oh right | 09:11 |
| olofk_ | Looks like I'm looking for this: git rebase --onto <new-parent> <old-parent> | 09:11 |
| olofk_ | or perhaps git pull --rebase | 09:14 |
| olofk_ | Or is that the other way around? | 09:15 |
| Powermaniac | Don't ask me xD | 09:15 |
| _franck_ | olofk_: I would do like hans told you, git remote add then cherry-pick | 09:23 |
| olofk_ | _franck_: Why? It sounds more complicated than a rebase? | 09:29 |
| stekern | olofk_: you can just run git fetch and then cherry-pick from FETCH_HEAD | 09:39 |
| stekern | I don't know if thats *the* way, but that's how I do it | 09:40 |
| stekern | pull -r is the wrong way, youll get your commits ontop of francks | 09:44 |
| olofk_ | git fetch... I understood it differs from git pull in some way, but I haven't had to figure out the difference yet | 09:47 |
| stekern | git pull is syntactic sugar for: git fetch; git merge | 09:47 |
| olofk_ | aha | 09:55 |
| stekern | and fetch just fetches data, it doesn't do any changes to your current branch | 10:05 |
| frubbl | olofk, http://git-scm.com/book/en/Distributed-Git-Maintaining-a-Project | 14:36 |
| --- Log closed Fri Oct 25 00:00:55 2013 | ||
Generated by irclog2html.py 2.15.2 by Marius Gedminas - find it at mg.pov.lt!