This shows you the differences between two versions of the page.
Both sides previous revision Previous revision Next revision | Previous revision Next revision Both sides next revision | ||
reproducibility [2015/12/11 11:59] fmassonn |
reproducibility [2016/01/14 19:54] xyepes [17 December 2015] |
||
---|---|---|---|
Line 252: | Line 252: | ||
More about compilation options can be found {{https:// | More about compilation options can be found {{https:// | ||
+ | |||
+ | |||
+ | ===== 9 December 2015 ===== | ||
+ | We had a meeting with usual people + Klaus and Uwe (SMHI) who are also tracking this reproducibility issue and are interested in what we are doing. Please visit [[https:// | ||
+ | |||
+ | The discussions were quite rich, and here is the summary in a few bullet points | ||
+ | * We have to be extremely **careful** when saying things like " | ||
+ | * SMHI is mostly interested in understanding what are the configurations under which EC-Earth is reproducible, | ||
+ | * Assessing reproducibility of a whole system is different from assessing reproducibility of one particular variable (e.g., Antarctic sea ice extent in winter). A good point of the Barker et al. paper referenced above is that their test is multivariate, | ||
+ | |||
+ | The topic is becoming extremely complex, far-reaching and our team looking into the topic is growing every month. On the other hand it has been a long-standing issue (almost one year now) and we need to have insights for the next EC-Earth meeting and the upcoming CMIP6. Here is a suggestion as how to continue the work: this should be split in two tasks | ||
+ | * **Developer aspect** - Xavi Yepes is now looking in the bit-for-bit reproducibility issue with EC-Earth 3.2. and for short (3-month) runs. SMHI (Uwe, Klaus) and KNMI (Philippe Le Sager) are aware of this. He is making several tests: | ||
+ | - Changing the number of processors in NEMO, IFS, both. | ||
+ | - Setting optimization to -O2 or -O3 | ||
+ | - Setting the -fp-model to precise, strict, source | ||
+ | * **User aspect** - Asif, François will continue adopting the " | ||
+ | |||
+ | ===== 15 December 2015 ===== | ||
+ | The **User aspect** experiments are launched. Ithaca' | ||
+ | |||
+ | ===== 17 December 2015 ===== | ||
+ | François and Xavier agreed that it is necessary to perform several executions changing technical aspects. Ideally, the following aspects should be all evaluated, but it is not feasible to handle it, because combinations grow exponentially. So, the parameters to try are: | ||
+ | |||
+ | * Compulsory: | ||
+ | * Code optimization: | ||
+ | * Regarding floating-point calculations: | ||
+ | * Usage of -xHost flag (best instructions according to host machine) | ||
+ | * Two processor combinations: | ||
+ | * IFS 320 and NEMO 288 | ||
+ | * IFS 128 and NEMO 64 | ||
+ | * Optional: | ||
+ | * Without -xHost | ||
+ | * Without -fp-model clause | ||
+ | * Try -fp-model source | ||
+ | * Explore more processor combinations | ||
+ | |||
+ | So, we should have 4 compulsory compilations: | ||
+ | * -O2 -fp-model precise -xHost | ||
+ | * -O2 -fp-model strict -xHost | ||
+ | * -O3 -fp-model precise -xHost | ||
+ | * -O3 -fp-model strict -xHost | ||
+ | |||
+ | And consequently, | ||
+ | |||
+ | Additional considerations: | ||
+ | |||
+ | * Use last EC-Earth 3.2beta release | ||
+ | * Enable key_mpp_rep | ||
+ | * 1 month, writing every day | ||
+ | * Use optimization to avoid mpi_allgather use at the northfold |