CUDA 10.1 on Ubuntu 18.04 problem

Install cuda according to the instruction https://developer.nvidia.com/cuda-downloads?target_os=Linux&target_arch=x86_64&target_distro=Ubuntu&target_version=1804&target_type=debnetwork

$ sudo dpkg -i Downloads/cuda-repo-ubuntu1804_10.1.105-1_amd64.deb
$ sudo apt-key adv --fetch-keys http://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/7fa2af80.pub
$ sudo apt update
$ sudo apt install cuda
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 cuda-runtime-10-1 : Depends: cuda-drivers (>= 418.39) but it is not going to be installed
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

Facing same issue.

sudo apt install cuda
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 cuda-runtime-10-1 : Depends: cuda-drivers (>= 418.39) but it is not going to be installed
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

Do you have at least this driver version installed?!?!

Added PPA and installed nvidia-driver-418

sudo add-apt-repository ppa:graphics-drivers/ppa 
sudo apt update 
sudo apt upgrade 
ubuntu-drivers devices 
sudo ubuntu-drivers autoinstall 
sudo apt install nvidia-driver-418

after that, it installed normally

sudo dpkg -i cuda-repo-ubuntu1804-10-1-local-10.1.105-418.39_1.0-1_amd64.deb  
sudo apt-key add /var/cuda-repo-10-1-local-10.1.105-418.39/7fa2af80.pub 
sudo apt-get update 
sudo apt-get install cuda

Did not work for me, ends with

The following packages have unmet dependencies:
 cuda : Depends: cuda-10-1 (>= 10.1.105) but it is not going to be installed
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.

I’m facing this problem as well and tracked it down to DPKG crashing when it tries to compile the included 418 driver - it is specific to the shipped driver - if I use the driver off the site nividia-418-418, it compiles but CUDA fails to recognize it (are you freaking kidding?! Get your sh!t together nvidia - every cuda package has something seriously wrong with it.)