On GPU's FP64/double-precision is generally poorly IEEE compliant and thus not so useful for scientific excellence. You have to pay extra for better performance than that. The vendors target the gaming/consumer market where FP64 accuracy is pretty much irrelevant. An E@H GPU workunit may finalise it's results on a CPU in order get sufficient double precision utility.
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
I'd like to add: Besides the observed poorly IEEE compliant FP64 computation of (some?) GPU types (task validation issues), FP64 usage depends on the specific GPU app. FP64 support is mandatory for some GPU apps, for others it is not.
an older comment of project admin Bernd Machenschalk (Sep 28, 2023) on GPU FP64:
The plan class (BRP7-opencl-intel_gpu) is set to require fp64 support [...]
In FGRP double precision is required only in the first stage before the FFT. The app does this on the CPU if the GPU lacks double precision support. In BRP7 double precision is used deeper in the computation, there is not much left to do for the GPU if you do that on the CPU. BRP4 is all single precision, though.
In the early days of GPU computing NVidia could emulate double precision computation in software (using two floats IIRC), but that was CUDA only.
On GPU's
)
On GPU's FP64/double-precision is generally poorly IEEE compliant and thus not so useful for scientific excellence. You have to pay extra for better performance than that. The vendors target the gaming/consumer market where FP64 accuracy is pretty much irrelevant. An E@H GPU workunit may finalise it's results on a CPU in order get sufficient double precision utility.
Cheers, Mike.
I have made this letter longer than usual because I lack the time to make it shorter ...
... and my other CPU is a Ryzen 5950X :-) Blaise Pascal
I'd like to add: Besides the
)
I'd like to add: Besides the observed poorly IEEE compliant FP64 computation of (some?) GPU types (task validation issues), FP64 usage depends on the specific GPU app. FP64 support is mandatory for some GPU apps, for others it is not.
an older comment of project admin Bernd Machenschalk (Sep 28, 2023) on GPU FP64:
https://einsteinathome.org/de/content/important-news-brp7-and-fgrpb1-work-eh?page=1#comment-217599