论文标题
对平行特征 - 光谱混合(CHASM)方案的绩效评估
Performance evaluations on the parallel CHAracteristic-Spectral-Mixed (CHASM) scheme
论文作者
论文摘要
关于6-D问题的确定性算法的绩效评估很少在文献中找到,除了弗拉索夫和鲍尔茨曼社区的一些最新进展[Dimarco等。 (2018),Kormann等。 (2019)],由于复杂性极高。因此,各种技术之间的详细比较对于相关领域的研究人员应很有用。我们试图对平行特征 - 元素混合(CHASM)方案进行彻底评估,以支持其使用情况。 Chasm在空间空间中利用了立方B-Spline的扩展,并在动量空间中的光谱膨胀,许多人可能在解决6-D相空间中解决经典和量子动力学方程时可能克服了计算负担。我们的目的是三管齐下的。首先,我们希望表明,通过施加一些有效的HERMITE边界条件,局部立方样条可以尽可能准确地近似于全球。其次,我们将说明采用截短的内核方法在计算具有单数符号的假差异操作员时的必要性,因为广泛使用的伪频谱法[Ringhofer(1990)]可能无法正确地应对奇异性。最后,我们进行了比较非分类的Lawson计划和Strang操作员分裂的比较。我们的数值结果证明了一阶段Lawson预测器方案的优势,而在精度和稳定性方面都比多阶段的方案以及分裂方案的优势。
Performance evaluations on the deterministic algorithms for 6-D problems are rarely found in literatures except some recent advances in the Vlasov and Boltzmann community [Dimarco et al. (2018), Kormann et al. (2019)], due to the extremely high complexity. Thus a detailed comparison among various techniques shall be useful to the researchers in the related fields. We try to make a thorough evaluation on a parallel CHAracteristic-Spectral-Mixed (CHASM) scheme to support its usage. CHASM utilizes the cubic B-spline expansion in the spatial space and spectral expansion in the momentum space, which many potentially overcome the computational burden in solving classical and quantum kinetic equations in 6-D phase space. Our purpose is three-pronged. First, we would like show that by imposing some effective Hermite boundary conditions, the local cubic spline can approximate to the global one as accurately as possible. Second, we will illustrate the necessity of adopting the truncated kernel method in calculating the pseudodifferential operator with a singular symbol, since the widely used pseudo-spectral method [Ringhofer (1990)] might fail to properly tackle the singularity. Finally, we make a comparison among non-splitting Lawson schemes and Strang operator splitting. Our numerical results demonstrate the advantage of the one-stage Lawson predictor-corrector scheme over multi-stage ones as well as the splitting scheme in both accuracy and stability.