协作式问题社区
所有问题
让问题相遇，让思考前行。
筛选
当前只显示公开问题。 登录后可以看到你所在问题组里的问题
10 道问题
向所有人开放
0 票
1 回答
47 浏览
依据 CASTOR3D 的公开文献，复现其求解方法与基准算例，开发与之对齐的计算模块
问题维基
我希望依据 CASTOR3D 的公开文献，独立实现其中的线性 MHD 稳定性求解方法，并复现文献中输入条件能够明确恢复的基准算例。 当前需要先厘清：控制方程与归一化、平衡输入、坐标与离散方式、边界条件，以及本征值与模结构的计算和比较方法。对于三维耦合、壁与真空处理，以及流和抗磁漂移等扩展，希望按文献逐项确认，分阶段实现。 我想先讨论三个问题： 1.…
0 票
0 回答
60 浏览
Double copy relation and KLT relation in AdS space
问题维基
Double copy relation and KLT relation reveal that gravity and closed strings are, in a precise sense, built from two copies of gauge theory and open strings. Beyond their computational power, they…
4 票
2 已采纳
554 浏览
When does a spectral gap imply exponential mixing?
For a reversible Markov chain on a finite state space, a spectral gap gives exponential decay of the variance, and the constant is explicit. The statement I keep seeing quoted for the non-reversible…
2 票
1 回答
301 浏览
Differentiating through an eigendecomposition with near-degenerate eigenvalues
The standard backward rule for a symmetric eigendecomposition has in it, which is fine right up until two eigenvalues approach each other. In our case they approach each other exactly where the…
2 票
0 回答
199 浏览
Preconditioner that works to 512 cores and falls apart at 1024
Strong scaling is close to ideal up to 512 ranks. At 1024 the iteration count roughly doubles and the wall time goes up. The partitioning is the same algorithm at both sizes and the subdomains are…
4 票
2 回答
972 浏览
What counts as having reproduced a published result?
A genuine question about practice rather than about a calculation. We re-ran an analysis from a paper using our own pipeline and got a number that agrees within the quoted uncertainty, but our…
2 票
0 回答
341 浏览
Sampling a transition that happens once in a billion steps
Direct simulation will not reach it, and the usual enhanced-sampling machinery wants a reaction coordinate I do not have — the transition is collective and every one-dimensional coordinate I have…
2 票
1 回答
228 浏览
Is a cache-oblivious stencil still worth it on current memory hierarchies?
The classic results are from machines with a very different ratio of bandwidth to compute. On our current nodes a straightforwardly blocked stencil with tuned tile sizes is beating our…
1 票
1 已采纳
178 浏览
Table 3 is off by a factor of two pi and the text is not
Either the table or the text is wrong, and they cannot both be right. The text gives the coupling in angular frequency and the table's caption says the same, but the values are consistent with…
1 票
0 回答
102 浏览
Notation for an average over configurations of an average over sources
This is a writing question and I am asking it anyway, because the last three manuscripts I refereed each invented their own and I could not follow any of them. The quantity is an average over gauge…
显示第 1–10 项，共 10 项
每一道问题，都是一次共同思考的邀请。