Hi I recently upgraded the OS from Ubuntu18.04 to Ubuntu20.04. Now I notice that when I do sudo apt-get upgrade, I have packages kept back:
The following packages have been kept back:
  build-essential cpp g++ gcc gfortran liblapack-dev liblapack3
0 upgraded, 0 newly installed, 0 to remove and 7 not upgraded.
I tried the methods mentioned here. To resolve this I tried
sudo apt-get dist-upgrade
but the output is the same as before.
I also tried sudo aptitude full-upgrade and the solution is also to keep the packages at their current version. The output is the following:
The following NEW packages will be installed:
  cpp-9{ab} g++-9{ab} gcc-9{ab} gfortran-9{ab} libasan5{ab} libgcc-9-dev{ab} libgfortran-9-dev{ab} libgfortran5{ab} libstdc++-9-dev{ab} 
  libubsan1{ab} 
The following packages will be upgraded:
  build-essential cpp g++ gcc gfortran liblapack-dev liblapack3 
7 packages upgraded, 10 newly installed, 0 to remove and 0 not upgraded.
Need to get 44.5 MB of archives. After unpacking 170 MB will be used.
The following packages have unmet dependencies:
 cpp-9 : Depends: gcc-9-base (= 9.3.0-17ubuntu1~20.04) but 9.4.0-1ubuntu1~18.04 is installed
 libgfortran-9-dev : Depends: gcc-9-base (= 9.3.0-17ubuntu1~20.04) but 9.4.0-1ubuntu1~18.04 is installed
 libasan5 : Depends: gcc-9-base (= 9.3.0-17ubuntu1~20.04) but 9.4.0-1ubuntu1~18.04 is installed
 libstdc++-9-dev : Depends: gcc-9-base (= 9.3.0-17ubuntu1~20.04) but 9.4.0-1ubuntu1~18.04 is installed
 libubsan1 : Depends: gcc-10-base (= 10.2.0-5ubuntu1~20.04) but 10.3.0-1ubuntu1~18.04~1 is installed
 g++-9 : Depends: gcc-9-base (= 9.3.0-17ubuntu1~20.04) but 9.4.0-1ubuntu1~18.04 is installed
 libgfortran5 : Depends: gcc-10-base (= 10.2.0-5ubuntu1~20.04) but 10.3.0-1ubuntu1~18.04~1 is installed
 gcc-9 : Depends: gcc-9-base (= 9.3.0-17ubuntu1~20.04) but 9.4.0-1ubuntu1~18.04 is installed
 gfortran-9 : Depends: gcc-9-base (= 9.3.0-17ubuntu1~20.04) but 9.4.0-1ubuntu1~18.04 is installed
 libgcc-9-dev : Depends: gcc-9-base (= 9.3.0-17ubuntu1~20.04) but 9.4.0-1ubuntu1~18.04 is installed
The following actions will resolve these dependencies:
  Keep the following packages at their current version:
-  build-essential [12.4ubuntu1 (now)]                
 
-  cpp [4:7.4.0-1ubuntu2.3 (now)]                     
 
-  cpp-9 [Not Installed]                              
 
-  g++ [4:7.4.0-1ubuntu2.3 (now)]                     
 
-  g++-9 [Not Installed]                              
 
-  gcc [4:7.4.0-1ubuntu2.3 (now)]                     
 
-  gcc-9 [Not Installed]                              
 
-  gfortran [4:7.4.0-1ubuntu2.3 (now)]                
 
-  gfortran-9 [Not Installed]                         
 
- libasan5 [Not Installed]                           
 
- libgcc-9-dev [Not Installed]                       
 
- libgfortran-9-dev [Not Installed]                  
 
- libgfortran5 [Not Installed]                       
 
- liblapack-dev [3.7.1-4ubuntu1 (now)]               
 
- liblapack3 [3.7.1-4ubuntu1 (now)]                  
 
- libstdc++-9-dev [Not Installed]                    
 
- libubsan1 [Not Installed]      
 
Can someone give me some suggestions? Thanks!
 
     
     
    