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  • How to check if a Webcam is broken?

    - by user84812
    I just bought an Acer Aspire 3830TG, it comes with an integrated 1.3M HD Webcam. Before buying it i tried with a bootable Lubuntu usb stick, everything worked well except for the webcam, which i thought I had to tweak. The thing is that it seems the camera should work with no problems in ubuntu. The driver is detected, I try dmesg | grep uvcvideo and the output is [ 12.226174] uvcvideo: Found UVC 1.00 device 1.3M HD WebCam (058f:b002) [ 12.245553] usbcore: registered new interface driver uvcvideo I've also tried using different software (guvcview is black when camera output is MJPG and turns to funny colors when YU12 or YV12, cheese is always black, camorama is always with funny colors...). I should have checked that it was working properly with the default os (windows) but now it's too late for that. I even booted with a official Ubuntu Quantal distro from the usb pen, and the results are the same. so, my question is: is there any way to check that the camera is righmt or broken? So, if it's broken, at least i can go to the shop, show them that it's really broken and get an external webcam for free, or st like that. cheers. UPDATE 1 Thanks, jrp. I run sudo lsinput, and the output info about my video is the following: /dev/input/event6 bustype : BUS_USB vendor : 0x58f product : 0xb002 version : 2 name : "1.3M HD WebCam" phys : "usb-0000:00:1a.0-1.3/button" bits ev : EV_SYN EV_KEY /dev/input/event7 bustype : BUS_HOST vendor : 0x0 product : 0x6 version : 0 name : "Video Bus" phys : "LNXVIDEO/video/input0" bits ev : EV_SYN EV_KEY With this info, i'm not pretty sure about running the luvcview command. If I run luvcview -d /dev/video0 -L, the output is the following: SDL information: Video driver: x11 A window manager is available Device information: Device path: /dev/video0 { pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1280, height = 720 } Time interval between frame: 1/7, 1/5, { discrete: width = 1280, height = 800 } Time interval between frame: 1/7, 1/5, { discrete: width = 1280, height = 960 } Time interval between frame: 1/7, 1/5, { discrete: width = 1280, height = 1024 } Time interval between frame: 1/7, 1/5, { pixelformat = 'MJPG', description = 'MJPEG' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1280, height = 720 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1280, height = 800 } Time interval between frame: 1/15, 1/10, 1/5, { discrete: width = 1280, height = 960 } Time interval between frame: 1/15, 1/10, 1/5, { discrete: width = 1280, height = 1024 } Time interval between frame: 1/15, 1/10, 1/5, { pixelformat = 'RGB3', description = 'RGB3' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1280, height = 720 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1280, height = 800 } Time interval between frame: 1/15, 1/10, 1/5, { discrete: width = 1280, height = 960 } Time interval between frame: 1/15, 1/10, 1/5, { discrete: width = 1280, height = 1024 } Time interval between frame: 1/15, 1/10, 1/5, { pixelformat = 'BGR3', description = 'BGR3' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1280, height = 720 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1280, height = 800 } Time interval between frame: 1/15, 1/10, 1/5, { discrete: width = 1280, height = 960 } Time interval between frame: 1/15, 1/10, 1/5, { discrete: width = 1280, height = 1024 } Time interval between frame: 1/15, 1/10, 1/5, { pixelformat = 'YU12', description = 'YU12' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1280, height = 720 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1280, height = 800 } Time interval between frame: 1/15, 1/10, 1/5, { discrete: width = 1280, height = 960 } Time interval between frame: 1/15, 1/10, 1/5, { discrete: width = 1280, height = 1024 } Time interval between frame: 1/15, 1/10, 1/5, { pixelformat = 'YV12', description = 'YV12' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1280, height = 720 } Time interval between frame: 1/30, 1/25, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1280, height = 800 } Time interval between frame: 1/15, 1/10, 1/5, { discrete: width = 1280, height = 960 } Time interval between frame: 1/15, 1/10, 1/5, { discrete: width = 1280, height = 1024 } Time interval between frame: 1/15, 1/10, 1/5, if i run luvcview by itself, the image is funny (blue and red colors, mainly, with myself in negative state). tx

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  • using isight camera in macbookpro(8,2) on ubuntu 12.04 virtualbox VM

    - by Kurt Spindler
    I'm having a lot of trouble using the built-in isight camera on my macbookpro8,2 (early 2011) from an ubuntu 12.04 virtual machine, run inside VirtualBox. The following is the log I get when I try to run guvcview ubuntu@ubuntu:~$ guvcview guvcview 1.5.3 ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.surround71 ALSA lib setup.c:565:(add_elem) Cannot obtain info for CTL elem (MIXER,'IEC958 Playback Default',0,0,0): No such file or directory ALSA lib setup.c:565:(add_elem) Cannot obtain info for CTL elem (MIXER,'IEC958 Playback Default',0,0,0): No such file or directory ALSA lib setup.c:565:(add_elem) Cannot obtain info for CTL elem (MIXER,'IEC958 Playback Default',0,0,0): No such file or directory ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.hdmi ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.modem ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline ALSA lib pcm.c:2217:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.phoneline ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib audio/pcm_bluetooth.c:1614:(audioservice_expect) BT_GET_CAPABILITIES failed : Input/output error(5) ALSA lib pcm_dmix.c:957:(snd_pcm_dmix_open) The dmix plugin supports only playback stream Cannot connect to server socket err = No such file or directory Cannot connect to server socket jack server is not running or cannot be started video device: /dev/video0 Init. FaceTime HD Camera (Built-in) (location: usb-0000:00:0b.0-1) { pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' } { discrete: width = 160, height = 120 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 176, height = 144 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 320, height = 240 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 352, height = 288 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 640, height = 480 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 1/10, { pixelformat = 'MJPG', description = 'MJPEG' } { discrete: width = 960, height = 540 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1024, height = 576 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { pixelformat = 'RGB3', description = 'RGB3' } { discrete: width = 160, height = 120 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 176, height = 144 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 320, height = 240 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 352, height = 288 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 640, height = 480 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 960, height = 540 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1024, height = 576 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { pixelformat = 'BGR3', description = 'BGR3' } { discrete: width = 160, height = 120 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 176, height = 144 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 320, height = 240 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 352, height = 288 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 640, height = 480 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 960, height = 540 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1024, height = 576 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { pixelformat = 'YU12', description = 'YU12' } { discrete: width = 160, height = 120 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 176, height = 144 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 320, height = 240 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 352, height = 288 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 640, height = 480 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 960, height = 540 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1024, height = 576 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { pixelformat = 'YV12', description = 'YV12' } { discrete: width = 160, height = 120 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 176, height = 144 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 320, height = 240 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 352, height = 288 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 640, height = 480 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1280, height = 720 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 960, height = 540 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, { discrete: width = 1024, height = 576 } Time interval between frame: 100/2997, 1/25, 1/24, 1/15, vid:05ac pid:8509 driver:uvcvideo checking format: 1196444237 VIDIOC_G_COMP:: Invalid argument compression control not supported fps is set to 1/25 drawing controls no codec detected for H264 no codec detected for MP3 - (lavc) Checking video mode 960x540@32bpp : OK Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable Could not grab image (select timeout): Resource temporarily unavailable write /home/ubuntu/.guvcviewrc OK free controls cleaned allocations - 100% Closing portaudio ...OK Closing GTK... OK ubuntu@ubuntu:~$ Any help would be greatly appreciated. Only clue I have is that I initially was having problems, tried using the old method of fixing isights (involving installing isight-firmware-tools) before realizing that I just hadn't turned on the VM setting to allow the VM to access the webcam. :) Anyway, I wonder if installing that messed something up. However, I think this is a red herring because I've: shut down and turned back on the Mac, restarted the VM, tried a different VM (for which I never installed isight-firmware-tools, and created an entirely new ubuntu vm. All instances have had this problem. Similarly, other viewers, such as cheese, avplay, avconv have had all various kinds of errors.

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  • Disable of discrete/native graphics on MacBook Retina when using apps like VMware, VLC, etc

    - by badkitteh
    I got a MacBook Pro Retina a few months ago and I'm really happy with it. However, since I do a lot of work in different environments/OSes, I make heavy use of VMware to have them with me when I'm on the road. The MBPr has a great battery life - as long as integrated graphics are being used. Unfortunately as soon as I launch VMware, the MacBook switches to discrete graphics and battery life is effectively halved. I noticed that after installing gfxCardStatus, and now I'm wondering if there is a way to force the integrated graphics being used all of the time, so I can enjoy maximum battery life. Thanks.

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  • Discrete and Continuous Classifier on Sparse Data

    - by Chris S
    I'm trying to classify an example, which contains discrete and continuous features. Also, the example represents sparse data, so even though the system may have been trained on 100 features, the example may only have 12. What would be the best classifier algorithm to use to accomplish this? I've been looking at Bayes, Maxent, Decision Tree, and KNN, but I'm not sure any fit the bill exactly. The biggest sticking point I've found is that most implementations don't support sparse data sets and both discrete and continuous features. Can anyone recommend an algorithm and implementation (preferably in Python) that fits these criteria? Libraries I've looked at so far include: Orange (Mostly academic. Implementations not terribly efficient or practical.) NLTK (Also academic, although has a good Maxent implementation, but doesn't handle continuous features.) Weka (Still researching this. Seems to support a broad range of algorithms, but has poor documentation, so it's unclear what each implementation supports.)

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  • On a dual-GPU laptop, is using the discrete GPU ever more power efficient?

    - by Mahmoud Al-Qudsi
    Given a laptop with a dual integrated/discrete GPU configuration, is it ever more power efficient to use the discrete GPU instead of the integrated? Obviously when writing an email or working on a spreadsheet, the integrated GPU will always use less power. But let's say you're doing something graphics-medium but not graphics-intensive/heavy - is there a point where it actually makes sense to fire up the discrete GPU, not for performance but for power-saving reasons? Off the top of my head, I can think of a scenario where the external GPU supports hardware decoding of a particular video codec - I'd imagine there is a "price point" where using the GPU saves more energy than decoding that fully in software would. But I think most GPUs, integrated or discrete, pretty much decode just the plain-Jane h264. But maybe there is something more complicated, perhaps if you're doing something like desktop/windowing animations or a flash animation on a website (not an embedded flash video) - maybe the discrete GPU will use enough less power to make up for switching to it? I guess this question can be summed up as to whether or not you can say beyond doubt that if you don't care for performance on a laptop with two GPUs, always use the integrated GPU for maximum battery life.

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  • Hybrid Graphics on Ubuntu 12.04 switching to discrete

    - by cfstras
    I have a Sony Vaio VPCCB-27FX with hybrid graphics. Using vgaswitcheroo enables me to switch my discrete card off to save power. Now when i want to switch to the discrete card for performance, my system freezes. I already tried logging out and killing x with service lightdm stop, but still, it freezes as soon as I echo DIS > switch. typing blindly, echo IGD > switch returns me to my console where it reads [ 179.555171] i915: switched off, but it seems the discrete card never gets switched on... running echo DDIS > switch gives me the following: [540....] [drm:atop_op_jump] *ERROR* atombios stuck in loop for more than 5secs aborting [540....] [drm:atom_execute_table_locked] *ERROR* atombios stuck executing CEE2 (len 62, WS 0, PS 0) @ 0xCEFE [540....] [drm:atom_execute_table_locked] *ERROR* atombios stuck executing BBF6 (len 1036, WS 4, PS 0) @ 0xBCF3 [540....] [drm:atom_execute_table_locked] *ERROR* atombios stuck executing BB8C (len 76, WS 0, PS 0) @ 0xBB94 [541....] [drm:r600_RING_TEST] *ERROR* radeon: ring test failed (scratch(0x8504)=0xFFFFFFFF) [541....] [drm:evergreen_resume] *ERROR* evergreen startup failed on resume after that, the atombios part repeats a few times. also, the terminal locks up again and sysrq+REISUB is my only rescue. Has anybody an idea how I can switch to my discrete card without the system locking up? #uname -srvmpio Linux 3.2.0-24-generic #39-Ubuntu SMP Mon May 21 16:52:17 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux #lsb_release -r Description: Ubuntu 12.04 LTS

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  • Discrete mathematics problem - Probability theory and counting

    - by Mohammad
    Hello All, I'm taking a discrete mathematics course, and I encountered a question and I need your help. I don't know if this is the right place for that though :) It says: Each user on a computer system has a password, which is six to eight characters long, where each character is an uppercase letter or a digit. Each password must contain at least one digit. How many possible passwords are there? The book solves this by adding the probabilities of having six,seven and eight characters long password. However, when he solves for probability of six characters he does this P6 = 36^6 - 26^6 and does P7 = 36^7 - 26^7 and P8 = 36^8 - 26^8 and then add them all I understand the solution, but my question is why doesn't calculating, P6 = 10*36^5 and the same for P7 and P8, work? 10 for the digit and 36 for the alphanumeric? Also, if anyone could give me another solution, other than the one in the book. Thank you very much :)

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  • How to disable discrete GPU using NVIDIA drivers?

    - by penzoiders
    I have a DELL studio XPS 13 (aka 1340) as of 12.04 most things run smoothly out of the box, but I have some power draining and warmness issues (if not to be called terrible heat issues) The system came with a NVIDIA GeForce 9500M (which has Hybrid SLI) and it shows up in "lspci" as these 2 cards 02:00.0 VGA compatible controller: NVIDIA Corporation G98 [GeForce 9200M GS] (rev a1) 03:00.0 VGA compatible controller: NVIDIA Corporation C79 [GeForce 9400M G] (rev b1) I had to install nvidia-current over noveau driver 'cause noveau does freeze the system after suspension. By installing nvidia-current and running nvidia-xconfig the resume process after suspension is fixed. By the way both with nvidia-current and noveau the system drains a lot of battery and heats up a lot. I suppose this is because the discrete GPU is always on. I don't really need 3D graphics on this system, if not the minimal to run unity and compiz for window management. So my question is: How do I disable, using nvidia-current, the discrete GPU 9200M and use only the integrated one 9400M? notes: In BIOS I have no option to disable discrete GPU This I think is not applicable because of the suspension-freeze issue (with noveau): https://help.ubuntu.com/community/HybridGraphics I've found this but I don't know which --sli option I should choose to fit my needs: http://manpages.ubuntu.com/manpages/hardy/man1/nvidia-xconfig.1.html My system has not optimus or cuda, but anyone can tell me if bumblebee can work for me?

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  • Pohlig–Hellman algorithm for computing discrete logarithms

    - by drelihan
    Hi Folks, I'm working on coding the Pohlig-Hellman Algorithm but I am having problem understand the steps in the algorithm based on the definition of the algorithm. Going by the Wiki of the algorithm: http://en.wikipedia.org/wiki/Pohlig%E2%80%93Hellman_algorithm I know the first part 1) is to calculate the prime factor of p-1 - which is fine. Howeever, I am not sure what I need to do in steps 2) and 3). Can someone help with explaining this in plain english (i) - or pseudocode. I want to code the solution myself obviously but I cannot make any more progress unless i understand the algorithm. Note: I have done a lot of searching for this and I read S. Pohlig and M. Hellman (1978). "An Improved Algorithm for Computing Logarithms over GF(p) and its Cryptographic Significance but its still not really making sense to me. Thanks in advance

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  • Coordinate geometry operations in images/discrete space

    - by avd
    I have images which have line segments, rays etc. I am representing these line segments using Bresenham algorithm (means whatever coordinates I get using this algorithm between two points). Now I want to do operations such as finding intersection point between two line segments, finding the projection of one vector onto other etc... The problem is I am not working in continuous space. The line segments are being approximated using Bresenham algorithm. So I want suggestions on what are the best and most efficient ways to do this? A link to C++ library or implementation would also be good enough. Please suggest some books which deal with such problems.

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  • Disable discrete AMD GPU

    - by Smajl
    My notebook has two graphic cards and it suffers from severe overheating after installing Ubuntu (no problem with Windows 7 on the same machine). I figured out that the problem may be in the graphic card and I would like to disable the discrete one. I followed some tutorials on this topic (for example http://planetoss.com/articles/how-to-disable-the-discrete-amd-graphics-card-in-linux/). But the problem is, that after executing the commands, nothing really happens and both GPU are still running. Here is what I have done: smajl@smajl-mini:~$ sudo chown smajl /sys/kernel/debug/vgaswitcheroo/switchsmajl@smajl-mini:~$ echo IGD > /sys/kernel/debug/vgaswitcheroo/switch smajl@smajl-mini:~$ sudo cat /sys/kernel/debug/vgaswitcheroo/switch 0:IGD:+:DynPwr:0000:01:05.0 1:DIS-Audio: :Pwr:0000:02:00.1 2:DIS: :DynPwr:0000:02:00.0 smajl@smajl-mini:~$ echo OFF > /sys/kernel/debug/vgaswitcheroo/switch smajl@smajl-mini:~$ sudo cat /sys/kernel/debug/vgaswitcheroo/switch 0:IGD:+:DynPwr:0000:01:05.0 1:DIS-Audio: :Pwr:0000:02:00.1 2:DIS: :DynPwr:0000:02:00.0 What am I missing here? Also, more on the overheating topic: 1) Installed TLP 2) updated system 3) set power setting mode to "power save" ...and nothing helps Tried same thing with Linux Mint without success. Is there anything else to try if I manage to disable the second GPU and the problem preserves? Otherwise I would have to get back to win in order not to melt my laptop.. :-/

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  • Discrete Math and Computing Course

    - by ShrimpCrackers
    I was recently admitted into a Computing and Software Systems program (basically software engineering) and one of the first courses I'll be taking is called Mathematical Principles of Computing. The course description: "Integrating mathematical principles with detailed instruction in computer programming. Explores mathematical reasoning and discrete structures through object-oriented programming. Includes algorithm analysis, basic abstract data types, and data structures." I'm not a fan of math, but I've been doing well in all my math classes mostly A's and B's ever since I started two years ago, and I've been doing math every quarter - never took a quarter without math - so I've been doing it all in sequence without gaps. However, I'm worried about this class. I've read briefly on what discrete math is and from what my advisor told me, its connection with computer science is that it has alot to do with proving algorithms. One thing that my instructors briefly touched on and never went into detail was proving algorithms, and when I tried, I just wasn't very good at mathematical induction. It's one of the things that I ignored every time it showed up in a homework problem (usually in Calculus III which I'm finishing up right now). Questions: 1. What can I expect from this class? 2. How can I prepare myself for this class? 3. Other tips? Thank you.

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  • Moving camera, or camera with discrete "screens"?

    - by Jacob Millward
    I'm making a game with a friend, but having trouble deciding on a camera style. The basic idea for the game, is having a randomly generated 2-dimensional world, with settlements in it. These settlements would have access to different resources, and it would be the job of the player to create bridges and ladders and links between these villages so they can trade. The player would advance personally by getting better gear, fighting monsters and looking for materials in the world, in order to craft and trade them at the settlements. My friend wants to use an old-style camera, where the world is split into a discrete number of screens that the player moves between. Similar to early Zelda dungeons, or Knytt Stories. This is opposite to me, as I want a standard camera that follows the player around as I feel the split-screen style camera limits the game. Can anyone argue the case either way? We've hit a massive roadblock here and can't seem to get past it.

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  • Switching between Discrete and Integrated GPUs

    - by void-pointer
    Hello everyone, I develop CUDA applications on my Alienware M17x portable back-breaker, which has two discrete GTX 285M GPUs and one integrated GeForce 9400M GPU. I can currently switch between them using NVIDIA's software, but I would like the ability to do so within my applications for purposes of benchmarking and general convenience. Apparently this requires the "NDA version" of NVIDIA's Driver API, which I know not how to obtain. Would using this API be the only way to accomplish what I seek, and if so, how would I obtain it? A solution using Windows APIs would also be acceptable, though less preferable to one which would leverage a cross-platform API. I have created a similar thread concerning the matter on NVIDIA's forum, which is down at the time of this writing. Thanks for reading my question; it is much appreciated!

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  • Ubuntu 14.04 doesn't detect my discrete GPU

    - by user258887
    I recently purchased a laptop with an Nvidia GeForce 860m, and have installed Ubuntu 14.04. On my old laptop I had 12.04, which automatically filled Additional Drivers with Nvidia drivers. But on this computer, the only thing in Additional Drivers is Qualcomm. So I manually installed Nvidia, but X Server Settings doesn't seem to detect any GPU... lspci | grep VGA reports only my integrated Intel GPU, but lspci -v reports many things, including the Nvidia GPU: 01:00.0 3D controller: NVIDIA Corporation GM107M [GeForce GTX 860M] (rev a2) Subsystem: ASUSTeK Computer Inc. Device 157d Flags: fast devsel, IRQ 16 Memory at ec000000 (32-bit, non-prefetchable) [size=16M] Memory at c0000000 (64-bit, prefetchable) [size=256M] Memory at d0000000 (64-bit, prefetchable) [size=32M] I/O ports at e000 [size=128] Expansion ROM at ed000000 [disabled] [size=512K] Capabilities: access denied Don't know what any of that means. Not sure if it's supposed to say 'access denied'... I need my GPU to do CUDA and OpenGL programming. What else can I do to figure out why this isn't working?

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  • Laptop, unable to install discrete graphics card GTX 880M

    - by FoxyShadoww
    So I've bought the GT70 2PE Dominator Pro a few weeks ago and I installed Zorin OS 9 Ultimate on it. Today I tried to install the Nvidia drivers on my laptop since it has the GTX 880M, but my system became unbootable. Can anyone help me with this issue? I will write down what I've tried so far. This is what I've tried so far: Downloaded the newest Nvidia drivers from their website. Pressed CTRL+ALT+F2 to open the terminal page thingy. Logged in and got root access. Stopped the lightdm service. Ran the NVIDIA-Linux-x86_64-340.32.run installer. Pressed the accept button and right after that it told me the following message: The distribution-provided pre-install script failed! Continue installation anyway?. When I install anyway, it will crash my system and makes it unbootable, Does anyone know how to use my GTX 880M? Do I need to enable it on boot time somehow? Thanks for the support, Sapphire ~

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  • GUVCVIEW errors

    - by Brian Snapp
    I had GUVCVIEW working once before. it suddenly quit working. This is the error I receive........ bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) bt_audio_service_open: connect() failed: Connection refused (111) video device: /dev/video0 /dev/video0 - device 1 Init. Intergrated Webcam (location: usb-0000:00:1a.7-2) { pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1024, height = 768 } Time interval between frame: 1/9, 1/5, { discrete: width = 1280, height = 1024 } Time interval between frame: 1/9, 1/5, checking format: 1196444237 Format unavailable: 1196444237. Init v4L2 failed !! Init video returned -2 trying minimum setup ... video device: /dev/video0 /dev/video0 - device 1 Init. Intergrated Webcam (location: usb-0000:00:1a.7-2) { pixelformat = 'YUYV', description = 'YUV 4:2:2 (YUYV)' } { discrete: width = 640, height = 480 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 352, height = 288 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 320, height = 240 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 176, height = 144 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 160, height = 120 } Time interval between frame: 1/30, 1/20, 1/15, 1/10, 1/5, { discrete: width = 1024, height = 768 } Time interval between frame: 1/9, 1/5, { discrete: width = 1280, height = 1024 } Time interval between frame: 1/9, 1/5, checking format: 1448695129 Requested Format unavailable: get width 640 height 480 vid:0c45 pid:6410 driver:uvcvideo (guvcview:4079): Gtk-CRITICAL **: gtk_hscale_new_with_range: assertion `min < max' failed (guvcview:4079): Gtk-CRITICAL **: gtk_scale_set_draw_value: assertion `GTK_IS_SCALE (scale)' failed Segmentation fault I suppose the problem lies in the fact, that I cannot locate a configuration file to edit. Any help in where this file may lie? I have tried searching for any/everything related to guvcview, and have had zero success. Thank you for taking the time to read this, and hopefully providing a solution..

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  • how to apply Discrete wavelet transform on image

    - by abuasis
    I am implementing an android application that will verify signature images , decided to go with the Discrete wavelet transform method (symmlet-8) the method requires to apply the discrete wavelet transform and separate the image using low-pass and high-pass filter and retrieve the wavelet transform coefficients. the equations show notations that I cant understand thus can't do the math easily , also didn't know how to apply low-pass and high-pass filters to my x and y points. is there any tutorial that shows you how to apply the discrete wavelet transform to my image easily that breaks it out in numbers? thanks alot in advance.

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  • Plotting an Arc in Discrete Steps

    - by phobos51594
    Good afternoon, Background My question relates to the plotting of an arbitrary arc in space using discrete steps. It is unique, however, in that I am not drawing to a canvas in the typical sense. The firmware I am designing is for a gcode interpreter for a CNC mill that will translate commands into stepper motor movements. Now, I have already found a similar question on this very site, but the methodology suggested (Bresenham's Algorithm) appears to be incompatable for moving an object in space, as it only relies on the calculation of one octant of a circle which is then mirrored about the remaining axes of symmetry. Furthermore, the prescribed method of calculation an arc between two arbitrary angles relies on trigonometry (I am implementing on a microcontroller and would like to avoid costly trig functions, if possible) and simply not taking the steps that are out of the range. Finally, the algorithm only is designed to work in one rotational direction (e.g. counterclockwise). Question So, on to the actual question: Does anyone know of a general-purpose algorithm that can be used to "draw" an arbitrary arc in discrete steps while still giving respect to angular direction (CW / CCW)? The final implementation will be done in C, but the language for the purpose of the question is irrelevant. Thank you in advance. References S.O post on drawing a simple circle using Bresenham's Algorithm: "Drawing" an arc in discrete x-y steps Wiki page describing Bresenham's Algorithm for a circle http://en.wikipedia.org/wiki/Midpoint_circle_algorithm Gcode instructions to be implemented (see. G2 and G3) http://linuxcnc.org/docs/html/gcode.html

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  • Removing the contents of a Chan or MVar in a single discrete step

    - by Bill
    I'm writing a discrete simulation where request values from multiple threads accumulate in a centralized queue. Every n milliseconds, a manager wakes up to process requests. When the manager wakes up, it should retrieve all of the contents of the central queue in a single discrete step. While processing these, any client threads attempting to submit to the queue should block. When processing completes, the queue reopens and the manager goes back to sleep. What's the best way to do this? The retry behavior of STM isn't really what I want. If I use a Chan or MVar, there's no way to prevent clients from enqueuing additional requests during processing. One approach is to use an MVar as a mutex on a Chan holding the queue. Are there other ways to do this?

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  • What Precalculus knowledge is required before learning Discrete Math Computer Science topics?

    - by Ein Doofus
    Below I've listed the chapters from a Precalculus book as well as the author recommended Computer Science chapters from a Discrete Mathematics book. Although these chapters are from two specific books on these subjects I believe the topics are generally the same between any Precalc or Discrete Math book. What Precalculus topics should one know before starting these Discrete Math Computer Science topics?: Discrete Mathematics CS Chapters 1.1 Propositional Logic 1.2 Propositional Equivalences 1.3 Predicates and Quantifiers 1.4 Nested Quantifiers 1.5 Rules of Inference 1.6 Introduction to Proofs 1.7 Proof Methods and Strategy 2.1 Sets 2.2 Set Operations 2.3 Functions 2.4 Sequences and Summations 3.1 Algorithms 3.2 The Growths of Functions 3.3 Complexity of Algorithms 3.4 The Integers and Division 3.5 Primes and Greatest Common Divisors 3.6 Integers and Algorithms 3.8 Matrices 4.1 Mathematical Induction 4.2 Strong Induction and Well-Ordering 4.3 Recursive Definitions and Structural Induction 4.4 Recursive Algorithms 4.5 Program Correctness 5.1 The Basics of Counting 5.2 The Pigeonhole Principle 5.3 Permutations and Combinations 5.6 Generating Permutations and Combinations 6.1 An Introduction to Discrete Probability 6.4 Expected Value and Variance 7.1 Recurrence Relations 7.3 Divide-and-Conquer Algorithms and Recurrence Relations 7.5 Inclusion-Exclusion 8.1 Relations and Their Properties 8.2 n-ary Relations and Their Applications 8.3 Representing Relations 8.5 Equivalence Relations 9.1 Graphs and Graph Models 9.2 Graph Terminology and Special Types of Graphs 9.3 Representing Graphs and Graph Isomorphism 9.4 Connectivity 9.5 Euler and Hamilton Ptahs 10.1 Introduction to Trees 10.2 Application of Trees 10.3 Tree Traversal 11.1 Boolean Functions 11.2 Representing Boolean Functions 11.3 Logic Gates 11.4 Minimization of Circuits 12.1 Language and Grammars 12.2 Finite-State Machines with Output 12.3 Finite-State Machines with No Output 12.4 Language Recognition 12.5 Turing Machines Precalculus Chapters R.1 The Real-Number System R.2 Integer Exponents, Scientific Notation, and Order of Operations R.3 Addition, Subtraction, and Multiplication of Polynomials R.4 Factoring R.5 Rational Expressions R.6 Radical Notation and Rational Exponents R.7 The Basics of Equation Solving 1.1 Functions, Graphs, Graphers 1.2 Linear Functions, Slope, and Applications 1.3 Modeling: Data Analysis, Curve Fitting, and Linear Regression 1.4 More on Functions 1.5 Symmetry and Transformations 1.6 Variation and Applications 1.7 Distance, Midpoints, and Circles 2.1 Zeros of Linear Functions and Models 2.2 The Complex Numbers 2.3 Zeros of Quadratic Functions and Models 2.4 Analyzing Graphs of Quadratic Functions 2.5 Modeling: Data Analysis, Curve Fitting, and Quadratic Regression 2.6 Zeros and More Equation Solving 2.7 Solving Inequalities 3.1 Polynomial Functions and Modeling 3.2 Polynomial Division; The Remainder and Factor Theorems 3.3 Theorems about Zeros of Polynomial Functions 3.4 Rational Functions 3.5 Polynomial and Rational Inequalities 4.1 Composite and Inverse Functions 4.2 Exponential Functions and Graphs 4.3 Logarithmic Functions and Graphs 4.4 Properties of Logarithmic Functions 4.5 Solving Exponential and Logarithmic Equations 4.6 Applications and Models: Growth and Decay 5.1 Systems of Equations in Two Variables 5.2 System of Equations in Three Variables 5.3 Matrices and Systems of Equations 5.4 Matrix Operations 5.5 Inverses of Matrices 5.6 System of Inequalities and Linear Programming 5.7 Partial Fractions 6.1 The Parabola 6.2 The Circle and Ellipse 6.3 The Hyperbola 6.4 Nonlinear Systems of Equations

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  • Discrete seekbar in Android app?

    - by vee
    i would like to create a seekbar for an Android app that allows the user to select a value between -5 and 5 (which maps to "strongly disagree" and "strongly agree"). how do i make a seekbar with discrete values? or is there a better UI widget i could use for this? thanks.

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  • R library for discrete Markov chain simulation

    - by stevejb
    Hello, I am looking for something like the 'msm' package, but for discrete Markov chains. For example, if I had a transition matrix defined as such Pi <- matrix(c(1/3,1/3,1/3, 0,2/3,1/6, 2/3,0,1/2)) for states A,B,C. How can I simulate a Markov chain according to that transition matrix? Thanks,

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