does not work in my case.    Terminal:/$ sudo add-apt-repository ppa:/alexlarsson/flatpak Output:Err:17 http://ppa.launchpad.net/alexlarsson/flatpak/ubuntu cosmic Release         404  Not Found [IP: 91.189.95.83 80]
When updating, I get the following error message:   W: The repository 'http://ppa.launchpad.net/mc3man/trusty-media/ubuntu xenial Release' does not have a Release file.   Here, I find another statement on this error:   This recommends removing certain PPAs; and, I'm not sure if I should do that since it might mean not getting the updates that I need.    Is this what I should do?
C#: How to create an attribute on a method triggering an event when it is invoked? I installed or upgraded to Ubuntu 16.04, but I'm having some problems with my graphics card.   The display is blank The display flickers Items on the screen do not display correctly Certain programs complain of graphics issues The computer boots to low-graphics mode Your specific issue may not be here, but try the solutions described in the answers anyway.   This question is very broad, but each one of these issues likely has one solution.    If you are experiencing a login loop, check the last part of my answer.    If you experience one of the listed issues and have your own solution (mine didn't work, or there's a faster way), feel free to post another POLITE answer, describing your problem and how you fixed it.    Those attempting to install Ubuntu, please refer to the section titled: If you are unable to enter a TTY or are trying to install Ubuntu. What is the amplitude of a light wave? Referring to this question   I'm curious about what is a amplitude of a light wave. Especially for light from a thermic source. Before upgrading to 14.04 when I clicked on a file in the dash, it opened the file.   This still happens on my 12.04 machine.  In 14.04 when I click on a file in dash search results, it offers me 3 options: 'Email', 'Open' and 'Show in Folder'.  How can I get back the previous behaviour - i.e. to immediately open the files on the first click? pyPdf for IndirectObject extraction Following this example, I can list all elements into a pdf file  import pyPdf pdf = pyPdf.PdfFileReader(open("pdffile.pdf")) list(pdf.pages) # Process all the objects. print pdf.resolvedObjects   now, I need to extract a non-standard object from the pdf file.   My object is the one named MYOBJECT and it is a string.  The piece printed by the python script that concernes me is:  {'/MYOBJECT': IndirectObject(584, 0)}   The pdf file is this:  558 0 obj &lt;&lt;/Contents 583 0 R/CropBox[0 0 595.22 842]/MediaBox[0 0 595.22 842]/Parent 29 0 R/Resources   &lt;&lt;/ColorSpace &lt;&lt;/CS0 563 0 R&gt;&gt;     /ExtGState &lt;&lt;/GS0 568 0 R&gt;&gt;     /Font&lt;&lt;/TT0 559 0 R/TT1 560 0 R/TT2 561 0 R/TT3 562 0 R&gt;&gt;     /ProcSet[/PDF/Text/ImageC]     /Properties&lt;&lt;/MC0&lt;&lt;/MYOBJECT 584 0 R&gt;&gt;/MC1&lt;&lt;/SubKey 582 0 R&gt;&gt; &gt;&gt;     /XObject&lt;&lt;/Im0 578 0 R&gt;&gt;&gt;&gt;   /Rotate 0/StructParents 0/Type/Page&gt;&gt; endobj ... ... ... 584 0 obj &lt;&lt;/Length 8&gt;&gt;stream  1_22_4_1     ---&gt;&gt;&gt;&gt;  this is the string I need to extract from the object  endstream endobj   How can I follow the 584 value in order to refer to my string (under pyPdf of course)?? How many copies of the DeLorean time machine co-existed in the Back to the Future series? Projectile Motion - Arrow In a 2D game, I simply want to draw the trajectory of an arrow in flight. With the code below, the trajectory (the parabola) looks right, but the angle (or rotation) or the arrow isn't.   float g = -9.8f; float x = (launchVelocity * time); float y = (launchVelocity * time) + (0.5f * g * (float)Math.Pow(time, 2)); float angle = (float)Math.Tanh(y / x);   What am I missing? Thanks. Unable to disable assignment rules I have a condition where I need to disable standard Lead Assignment Rules if certain criteria are met.   if(emailWithAccIdMap.containsKey(ledRec.Email) &amp;&amp; emailWithAccIdMap.get(ledRec.Email) != null &amp;&amp; !openOppMap.isEmpty() &amp;&amp; openOppMap.get(emailWithAccIdMap.get(ledRec.Email)) != null &amp;&amp; openOppMap.get(emailWithAccIdMap.get(ledRec.Email)).Owner.isActive ==true){                     ledRec.Status = 'Duplicate';                     System.debug('Changing the Status');                     //then assign the original lead owner to new lead owner                     ledRec.OwnerId = openOppMap.get(emailWithAccIdMap.get(ledRec.Email)).OwnerId;                     ledRec.Account_Name__c = openOppMap.get(emailWithAccIdMap.get(ledRec.Email)).AccountId;                     ledRec.Field_for_Lead_Workflow__c = true;                     Database.DMLOptions dmo = new Database.DMLOptions();                     dmo.assignmentRuleHeader.useDefaultRule = false;                     ledRec.setOptions(dmo);                     //since owner is assigned, it shouledRec not pass through round robin                     ledRec.checkAssignment__c = false;  }   This is my code snippet which is running on before insert. The control is entering the IF condition as the debug statement is getting printed. Yet, the owner assigned through this snippet is being overridden by the assignment rules.  I also tried executing this in after insert trigger context but it did not work. Can somebody tell me what I'm doing wrong? Thunderbolt 2 docks have been quite expensive and they will be obsolete once I purchase the new Macbooks with USB-C ports. I currently use a 2014 MacBook Pro with Thunderbolt 2 ports, and I want to futureproof my purchase by acquiring a cheaper USB-C dock now.  The cheapest Thunderbolt 2 dock costs around $200 while USB-C docks cost around $30. Being able to use a USB-C dock with older Thunderbolt 2 Macbook Pros would not only be cheaper but also allows me to use the same USB-C dock if I decided to upgrade to a future Macbook.  For that to work I need a Thunderbolt 2 (male) to USB-C female adaptor, after some searching it doesn't seem to exist. Is there a reason why something like this hasn't been made? Or is the USB-C specification designed such that it is impossible? (hence businesses can still continue to sell expensive Thunderbolt 2 docks...)  I will accept an answer that meets the following requirements:   If there is such an adapter please give a link and some form of evidence that these would have 100% compatibility with USB-C docks. If there is no such adapter please explain:   Is it impossible to produce? If not, why hasn't a vendor created one yet? I've explained that its a better financial investment than buying a TB2 dock... surely there's a market for those still using TB2 MBPs wanting to upgrade in the next couple of years. Not only docks but it would open a gateway to cheaper alternatives to those hideously expensive TB2 peripherals. Are planets actually moving in elliptical orbits around the Sun or do they move in circular orbits around their center of mass? In every derivation of Kepler's Laws that I have seen, we assume that the sun is stationary. However, in other places I have read that celestial bodies move about their barycentre (center of mass). So are planets actually moving in elliptical orbits around the Sun or do they move in circular orbits around their center of mass? WordPress twenty eleven sidebar on Pages I am using 2011 theme, any how I managed to get sidebar on single.php pages by installing child theme,  But now I want sidebar on pages,  How do I get it? Is Java's default value for Boolean 'true'? Can you use external money to pay trading commissions in tax-free and tax-deferred accounts? Does every linearly independent set of n vectors in $R^n$ forms a basis in $R^n$? Basically does a vector set that is linearly independent in $R^n$ automatically span $R^n$?  My initial thought is yes, but is there some counterexample that can disprove this? Area 51 reputation changes do not show up in the new Top Bar Is temperature a Lorentz invariant in relativity? This issue happens only on UEFI systems with enabled Secure Boot.  When I try to install DKMS modules like VirtualBox, Nvidia, or Broadcom drivers, they do not install and I get Required key not available when I try to modprobe them.  VirtualBox complains that vboxdrv is not loaded.  Broadcom wl driver is shown in lspci -k as a kernel module but is not in use. sudo modprobe wl throws Required key not available.  Also this issue may happen when I install some kernel modules from git sources.  This issue may appear after a kernel update as disabled wireless adapter, black screen after a reboot, etc.   How can I fix it? Making overview with linked detailed maps in QGIS? i want to create 4-5 detailed maps, and then an overview map that has rectangles that markes the locations of the detailed maps. Best case would be if the rectangles were links to the detailed map.   I have managed to make the overview and the rectangles, and think I know how to make the detailed maps one by one. The rectangles are drawn manually on the overview map. All layers that I plan on using are in the same QGIS project.  The final product that I hope to create would be the overview map on the first page, followed by the detailed maps. The overview would have links to the detailed maps, click on the rectangles to open the right detailed map.  Is there a way to link the detailed maps to the overview in QGIS 2.8 print composer?  I'm still not sure if I'm doing something wrong, when I try to create the overview. I want it to show the extents of all of my detailed maps.   Is this possible? Can I use Beetel 450TC1 as wireless router? Playing a video in full screen after startup