#11 Non-BFB test

1.Poster Title	Non-bit-for-bit solution reproducibility: a new test based on time step convergence
2.Authors	Hui Wan, Kai Zhang, Phil Rasch (pnl.gov), Balwinder Singh, Xingyuan Chen, Jim Edwards
3.Group	Atmosphere, SE
4.Experiment	N/A
5.Poster Category	Early Result
6.Submission Type	Presentation
7.Poster Link	11_HuiWan_poster_nonBFB
8.Lightning Talk Slide	HuiWan_one-slider_1_nonBFB.pdf

Abstract

An important category of testing method is currently missing in the ACME test suite: tests that determine whether non-bit-for-bit result changes are climate changing or not. We have developed a new method to test the solution reproducibility using the concept of time step convergence (TSC). The basic idea is that when the model equations have changed or when the code is not compiled/exercised correctly, the results will not converge to the reference solutions produced by a trusted model on a trusted computing environment.

This poster introduces the new method and shows examples of test results using CAM5.3 which is very similar to the atmosphere component of the ACME V0 model. The new TSC test is objective, easy to implement, and computationally efficient. We expect that the same methodology can be used for other components of the ACME model, and would be interested in discussing this with colleagues from other groups.