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Mins_2021_02_22

v3	v4
27	27	The discussion started recalling the undoubted benefits that the mixed precision approach has in terms of reduction of CPU time, reduction of data movement and reduction of I/O. The loss of accuracy can be fine tuned by means of the application of a tool which provides the user/developer with the list of variables to be kept in double precision.
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29		The ECMWF has developed a single precision version of NEMO 4.0.4 keeping very few variables in double precision and has experienced good results with acceptable loss of accuracy for short term predictions with NEMO SP (single precision) even in a coupled configuration. In contrast, the mixed precision trunk from the BSC keeps more variables in double precision to reduce the loss of accuracy and support longer runs.
	29	The ECMWF has developed a single precision version of NEMO 4.0.3 keeping very few variables in double precision and has experienced good results with acceptable loss of accuracy for short term predictions with NEMO SP (single precision) even in a coupled configuration. In contrast, the mixed precision trunk from the BSC keeps more variables in double precision to reduce the loss of accuracy and support longer runs.
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31	31	It was clearly stated that the double precision version of NEMO will not be affected by these changes, neither its results nor its computational performance.