I am sure you are right that this topic will keep being revisited but until the ability to cope with 80bit numbers appears on GPUs, my understanding is that it just isn't worth starting on. Once it is widely available, then it may well be worth working on but only if someone comes up with enough money to fund the work.

You have suggested having donations specifically for this but as these would almost certainly take away from the donations the project currently receives I think this is unlikely. The only ways I can see it happening is if a group of volunteer programmers with the skills and time plus hardware resources wish to take it on or someone taking it on as a masters/PHD project.

You STILL haven't got the point.

The Met Office models are a global standard.
They're run by researchers in a lot of places around the globe, who know that these models are stable, and that they can compare results with other people using them.

Every researcher currently using these models would have to switch to GPU programs and start again with their testing to see if they get consistent results.

Why bother when the current system works? And if they don't change, then we don't.

This issue just won�t stay dead. Every time that you think it have been safely staked through the heart it rises from the grave like Dracula in one of those old Hammer movies.

Hi Volvo

The CPDN models come from the UK Met Office where they consist of a version of the Unified Model. CPDN then adapts these models for its own use, for example deciding on the precise parameter values for particular experiments and compiling the models for the three platforms: Windows, Linux and Mac. Further CPDN adaptations can consist of time-slicing long models so that different computers take on different sections, and they all have to be stitched together.

But they all still consist of the Unified Model which the Met Office has adapted and developed continuously for years. The Met Office has a team of developers working on this, just as at the small number of other institutions that have developed models. I've seen a list of the names of one of these teams; it filled a computer screen. I also know that these organisations employ ace programmers.

To my knowledge these organisations all run their models on CPUs, in some cases on supercomputers. For example, a supercomputer in Tokyo is used for this purpose. If using GPUs were possible for the type of calculations required for climate models I'm pretty sure that all these model programmers in several institutions would already have harnessed this possibility. They have every motivation to complete model runs as quickly as possible because similar models based on the UM are used for weather prediction, for which they also run ensembles, albeit much smaller than ours at CPDN.

CPDN has two programmers who do not design the UM which runs on CPU.

We are all aware that running research tasks on computers uses electricity and that we need to ensure that our computers run as efficiently as possible. One way we can reduce the carbon footprint is be ensuring that as few models crash as possible.

The project's servers are already struggling to cope with the huge amounts of data being returned. Why do you want to increase this so drastically?

Well, AFAIK all currently active climate-models uses SSE2-optimizations, and my guess this means they're using double-precision. Since the fortran-compiler linked a few posts back is CUDA, and Nvidia-cards has abyssimally poor double-precision-speed of only 1/24 single-precision-performance, except if you pays $$$$ for the professional cards, even a top-end Nvidia-GTX780Ti only manages 210 GFLOPS at most. A quad-core (8 with HT) cpu on the other hand is around 100 GFLOPS. Meaning even best-case the Nvidia-GPU will only be 2x faster than CPU. In reality even 50% performance on GPU can be too high, meaning your "slow" CPU is outperforming your "fast" GPU.

So, unless can use single-precision on most of the calculations, a CUDA-version of CPDN is a waste of development-time.

Instead of CUDA, an OpenCL-compiler would be more interesting, since OpenCL also works with the much faster Amd-GPU's. But even with this additional speed, it's still unlikely can get a climate-model to run faster on GPU than CPU.