I use 2 monitors on Ubuntu 20.04, let's call them &quot;Old&quot; and &quot;New&quot;. Sometimes I only need &quot;New&quot;. They seem to work well with following exception: Problem:  When the computer is starting, no matter what option I use, the login screen always appears on the &quot;Old&quot;, even if I select &quot;New&quot; in the &quot;single display option&quot;. How can this be fixed?  Facts:  Just did a fresh install of Ubuntu 20.04. My monitors are both iiama. &quot;New&quot; is identified by the system as being monitor n°1 and &quot;Old&quot; as monitor n°2. Already tried setting one and then the other as the Primary Display. Already re-arranged monitors position (this was an issue on ubuntu 14.04 which was what I had) and put &quot;New&quot; both to the left and to the right.  Thanks to the links suggested by PRATAP I was able to solve this problem. There were several solutions but the only one that worked for me was  (quoting from the solution):  sudo cp ~/.config/monitors.xml ~gdm/.config/monitors.xml   sudo chown gdm:gdm ~gdm/.config/monitors.xml  And in the /etc/gdm3/custom.conf uncomment WaylandEnable=false (basically remove the # before Wayland)  sudo gedit /etc/gdm3/custom.conf  IMPORTANT!: some of the users referred they had to go into recovery mode to revert this situation because they only got a blank screen and were unable to login. This was not my case as everything worked fine for me. For more information look at the links mentioned by PRATAP, specially the second one, there are other solutions proposed but they didn't work in my case.
On Ubuntu 18.04, I have connected my laptop to an external display and I am able to set the external display as primary and external display only mode. But when I turn on my laptop or log out from my session the display login screen is displayed only on my(internal) laptop screen. But once I login the display switches to external only and my laptop screen turns off as expected. Is there a way I can make the login screen appear only on the external screen on bootup or on logout as in 16.04? Also the login screen does not follow my cursor as in 16.04.
Get full name twice in Bibliography I use biblatex with style=authoryear and when there are two references of the same author in the bibliography there is just a dash. How can I get the full name in the second entry too? filling area between 2 functions, with shading NFL overtime: after a field goal, clock runs out on second team's possession Under the NFL's current "modified sudden death" overtime rules, if the first team scores a field goal, the second team is entitled to one more possession.  What happens if the clock runs out during that possession?  Suppose the score is tied 20-20 at the end of the 4th quarter. Team A wins the overtime coin toss and receives the kickoff to begin overtime.  After a long slow drive, Team A scores a field goal to make the score 23-20.  Now they kick off to Team B.  Team B is not able to score, and the overtime period ends with Team B still in possession.  What happens?   is not very explicit on this point.  Article 4 (a) says:     There shall be a maximum of one 15-minute period, even if the second team has not had an opportunity to possess the ball or if its initial possession has not ended. If the score is tied at the end of the period, the game shall result in a tie.   I think this means that Team A wins, 23-20, but I am not completely sure.  Has this ever happened in a regular-season NFL game? Embedding C++ Objects into QML with Context Properties According to Qt5 documentation:  all public slots of C++ classes that inherit from QObject, are accessible from QML Here what I did:  C++  class MyClass : public QObject {     Q_OBJECT  public slots:     void doStuffFromQmlSlot()     {         qDebug() &lt;&lt; Q_FUNC_INFO;     }  public:     MyClass()     {         qDebug() &lt;&lt; Q_FUNC_INFO;     } };   my main.cpp contains:  MyClass myClass; QQmlEngine engine; engine.rootContext()-&gt;setContextProperty( "myclass", &amp;myClass ); QQmlComponent component( &amp;engine, QUrl::fromLocalFile("qml/qtquick-01/main.qml") ); component.create();   QML  import QtQuick 2.0  Rectangle {     width: 360     height: 360     Text {         text: qsTr("Hello World")         anchors.centerIn: parent     }     MouseArea {         anchors.fill: parent         onClicked: {             myclass.doStuffFromQmlSlot();              Qt.quit();         }     } }   Actually the QtCreator seems to recognixe the exposed myclass object into the QML as it enables auto-completion of both class name (myclass) and the public slot doStuffFromQmlSlot(). When I run the application I unfortunately got the following error:  ReferenceError: myclass is not defined  Any clue on what I'm doing wrong? Allow only alphanumeric characters for a UITextField Why does a helium filled balloon move forward in a car when the car is accelerating? Accessing UI thread handler from a service Add affiliations to the authors' name in the article class Is $\sum\limits_{n=1}^{\infty}\frac{n!}{n^n}$ convergent? How do I enable the "Universe" repository? How do I get to the Universe Repository in supported versions of Ubuntu? Working with systems with Perfect Multicollinearity I am working with a time-series dataset that is based on demand-supply dynamics with several variables.  THe sample data for one time period is: &gt; data # A tibble: 19 x 6    Pred_error_A Pred_error_B  Pred_error_C  Pred_error_D  Pred_error_E  Pred_error_Target                  &lt;dbl&gt;         &lt;dbl&gt;          &lt;dbl&gt;      &lt;dbl&gt;      &lt;dbl&gt;           &lt;dbl&gt;  1            -0.45           1.72          -0.170      1.85       -0.01          -0.7    2            -0.45           1.72          -0.170      2.35       -0.01          -1.2    3            -0.45           1.92          -0.170      2.35       -0.01          -1      4            -0.0500         0.37          -0.12       1.65       -0.01          -1.5    5             0             -0.840         -0.12       0.950      -0.01          -1.7    6             0             -0.200         -0.12       1.35       -0.01          -1.5    7             0             -0.460         -0.12       1.35       -0.01          -1.8    8             0             -0.520         -0.12       1.05       -0.01          -1.5    9             0             -0.340         -0.12       1.05       -0.01          -1.4   10             0             -0.340         -0.12       1.35       -0.01          -1.7   11             0             -0.110         -0.12       1.05       -0.01          -1.2   12             0             -0.110         -0.12       0.850      -0.01          -1     13             0              0             -0.12       0.350      -0.01          -0.4   14             0              0             -0.12      -0.15       -0.01           0.100 15             0              0             -0.12      -0.350      -0.01           0.300 16             0              0             -0.02       0          -0.01          -0.1   17             0              0              0          0           0              0     18             0              0              0          0           0              0     19             0              0              0          0           0              0   I was working on a regression for each time period with data and wanted to find the relative importance of regressors in explaining the target variable ( Pred_error_A through E and dependent variable is Pred_error_Target ) using relaimpo package in R. However, I soon realized I can't use regression setting because of near to perfect collinearity and hence no relative importance values. Is there a way to go around this? Or, can I use any other method (instead of regression)? Any suggestions will be useful. The predictors are near to perfect and each one is important. I can't exclude any single one and I need the relative importance of all 5 regressors. I am also trying XGBoost as an alternative. However, I am not sure if it takes care of multicollinearity. Transform fancy usage messages in 1D string Where and why do I have to put the "template" and "typename" keywords? Creating square buffer around point feature using ArcGIS for Desktop? I would like to create a square buffer from a point feature but I do not understand the code that goes into it.   Similar questions have been asked on the forums.esri website but that was over 10 years ago, and it did not work when I tried the code.  How do I create a square buffer from a point feature? Wavy stream of liquid While pouring a liquid into a glass from a bottle, some streams have a wavy shape, like the one in the following photo:    What causes the stream to be of such a shape? How to include audio file in PDF How do I include audio file, or should I say, link to audio file in PDF?   Audio should be playable "from PDF directly", without opening any additional window. Is it possible to attach audios to PDF     then so I can manipulate only with     that file, without being bothered     with copying folders where those     audio files would reside?   I saw that 1. is definitely doable (but don't know how) and I'm interested if second one is also possible (while compiling .tex file) since I know that some files (like graphs and tables) can be attached in PDF, but after it's generated.   Button for playing audio from document that uses this trick. What causes the portraits of Wizards to behave interactively? Where to declare environment variables? What are correct places for:   Global environment variables meant to affect all users? User-specific environment variables? I have a list of integers, List&lt;Integer&gt; and I'd like to convert all the integer objects into Strings, thus finishing up with a new List&lt;String&gt;.  Naturally, I could create a new List&lt;String&gt; and loop through the list calling String.valueOf() for each integer, but I was wondering if there was a better (read: more automatic) way of doing it? My table is like this:  Sitecode    Month  Amount --------    -----  ------ XX          Jan     1000 XX          Jan     3000 XX          Apr     3000 XX          Apr     1000   What I want is, to show the result something like this:  Sitecode    MonthJAN   MonthAPR --------    --------   -------- XX          4000       4000