Let's pretend that there is a troll/demon living in your computer named Optimus. He has the power to unplug one GPU and replace it with another. He has been given an NVidia GPU and an Intel GPU. If he has decided that now is the time for an Intel GPU, then you do not have access to the disconnected NVidia or the OpenCL driver associated with it.
If I were designing the software for that troll's brain, I'd teach him to listen for calls to CUDA or OpenCL and accept them as directive to power up the NVIdia -- but I didn't design that software. It might get tricky, though because it's possible to install an OpenCL driver for the Intel iGPU (which FAH doesn't support) so somehow it would have to work both ways.
ERROR: There is no registered Platform called "OpenCL"
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