wget https://download.01.org/gfx/ubuntu/16.04/main/pool/main/i/intel-graphics-update-tool/intel-graphics-update-tool_2.0.2_amd64.deb
sudo dpkg -i intel-graphics-update-tool_2.0.2_amd64.deb
sudo intel-graphics-update-tool 
sudo apt-get install -f
sudo intel-graphics-update-tool 
wget $(echo "https://download".01.org/gfx/RPM-GPG-GROUP-KEY-ilg) -O - | sudo apt-key add -
sudo apt-get update

W:GPG error: https://download.01.org/gfx/ubuntu/16.04/main xenial InRelease: The following signatures couldn\'t be verified because the public key is not available: NO_PUBKEY 56A3DEF863961D39, W:The repository \'https://download.01.org/gfx/ubuntu/16.04/main xenial InRelease\' is not signed., W:Data from such a repository can\'t be authenticated and is therefore potentially dangerous to use., W:See apt-secure(8) manpage for repository creation and user configuration details., W:There is no public key available for the following key IDs:
56A3DEF863961D39  , E:Problem executing scripts APT::Update::Post-Invoke-Success \'if /usr/bin/test -w /var/cache/app-info -a -e /usr/bin/appstreamcli; then appstreamcli refresh > /dev/null; fi\', E:Sub-process returned an error code

wget --no-check-certificate https://download.01.org/gfx/RPM-GPG-KEY-ilg -O - | sudo apt-key add -
wget --no-check-certificate https://download.01.org/gfx/RPM-GPG-KEY-ilg-4 -O - | sudo apt-key add -

W:https://download.01.org/gfx/ubuntu/16.04/main/dists/xenial/InRelease: Signature by key 09D6EF97BFB38E916EF060E756A3DEF863961D39 uses weak digest algorithm (SHA1), E:Problem executing scripts APT::Update::Post-Invoke-Success \'if /usr/bin/test -w /var/cache/app-info -a -e /usr/bin/appstreamcli; then appstreamcli refresh > /dev/null; fi\', E:Sub-process returned an error code

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 09D6EF97BFB38E916EF060E756A3DEF863961D39
sudo apt-get update
sudo pkill -KILL appstreamcli
wget -P /tmp https://launchpad.net/ubuntu/+archive/primary/+files/appstream_0.9.4-1ubuntu1_amd64.deb https://launchpad.net/ubuntu/+archive/primary/+files/libappstream3_0.9.4-1ubuntu1_amd64.deb
sudo dpkg -i /tmp/appstream_0.9.4-1ubuntu1_amd64.deb /tmp/libappstream3_0.9.4-1ubuntu1_amd64.deb
sudo apt-get update

Error running transaction: GDBus.Error:org.debian.apt.TransactionFailed: error-dep-resolution-failed: The following packages have unmet dependencies:

libgles1-mesa: Depends: libglapi-mesa (= 12.0.6-0ubuntu0.16.04.1) but 17.0.7-0ubuntu0.16.04.1 is to be installed

The following packages have unmet dependencies:

libgles1-mesa: Depends: libglapi-mesa (= 12.0.6-0ubuntu0.16.04.1) but 17.0.7-0ubuntu0.16.04.1 is to be installed

sudo add-apt-repository ppa:paulo-miguel-dias/pkppa && sudo apt-get update

https://software.intel.com/en-us/forums/opencl/topic/738108

mv install_OCL_driver.txt install_OCL_driver.sh
chmod 755 install_OCL_driver.sh
sudo su
./install_OCL_driver.sh install

...
Installation completed successfully.

Next steps:
1. Add OpenCL users to the video group: \'sudo usermod -a -G video USERNAME\'
   e.g. if the user running OpenCL host applications is foo, run: sudo usermod -a -G video foo

2. If you have Intel Pentium J4000 or Intel Celeron J3000, you will need to add:
   i915.preliminary_hw_support=1
   to the 4.7 kernel command line, in order to enable OpenCL functionality for these platforms.

3. Reboot into the patched 4.7 kernel

HINT: to boot into the 4.7 kernel do the following:
      1) Hold the "shift" button during boot
      2) When the GRUB menu appears, select "Advanced options for Ubuntu"
      3) Select the Linux 4.7.0.intel.r5.0 kernel from the list