论文标题
继续课程:在Riemannian歧管上定位动态系统的平衡。
Staying the course: Locating equilibria of dynamical systems on Riemannian manifolds defined by point-clouds
论文作者
论文摘要
我们介绍了一种方法,以连续定位黎曼流形动力学系统的平衡(稳态)。歧管不必以先验已知的地图集或光滑映射的零来表征。取而代之的是,它们可以通过点云来定义,并通过迭代过程根据需要进行采样。如果歧管是欧几里得空间,我们的方法遵循等线,曲线,曲线沿着vector field $ x $的方向是恒定的。对于通用矢量字段$ x $,等速线是平滑的曲线,每个平衡都位于等速线上。我们通过平行传输的使用将等线的定义概括为Riemannian歧管:广义的等法是曲线,$ x $的方向是彼此的平行传输。与欧几里得案一样,通用矢量字段$ x $的普遍等级是连接$ x $的平衡曲线。当歧管未知时,我们的算法可以被视为牛顿轨迹方法的扩展。 这项工作是由计算统计力学的动机,特别是模拟分子系统动力学的高维(随机)微分方程。通常,这些动力学集中在低维歧管附近,并在亚稳态平衡之间具有过渡(鞍点,单个不稳定方向)。我们使用迭代采样数据和等线来定位这些鞍点。将黑盒抽样方案(例如,马尔可夫链蒙特卡洛)与流动学习技术(此处介绍的情况下的扩散图)结合在一起,我们表明我们的方法可靠地定位了$ x $的平衡。
We introduce a method to successively locate equilibria (steady states) of dynamical systems on Riemannian manifolds. The manifolds need not be characterized by an a priori known atlas or by the zeros of a smooth map. Instead, they can be defined by point-clouds and sampled as needed through an iterative process. If the manifold is an Euclidean space, our method follows isoclines, curves along which the direction of the vector field $X$ is constant. For a generic vector field $X$, isoclines are smooth curves and every equilibrium lies on isoclines. We generalize the definition of isoclines to Riemannian manifolds through the use of parallel transport: generalized isoclines are curves along which the directions of $X$ are parallel transports of each other. As in the Euclidean case, generalized isoclines of generic vector fields $X$ are smooth curves that connect equilibria of $X$. Our algorithm can be regarded as an extension of the method of Newton trajectories to the manifold setting when the manifold is unknown. This work is motivated by computational statistical mechanics, specifically high dimensional (stochastic) differential equations that model the dynamics of molecular systems. Often, these dynamics concentrate near low-dimensional manifolds and have transitions (saddle points with a single unstable direction) between metastable equilibria. We employ iteratively sampled data and isoclines to locate these saddle points. Coupling a black-box sampling scheme (e.g., Markov chain Monte Carlo) with manifold learning techniques (diffusion maps in the case presented here), we show that our method reliably locates equilibria of $X$.