Department of Chemistry and the PULSE Institute, Stanford University, Stanford, California 94305, USA.
Department of Chemistry, Michigan State University, East Lansing, Michigan 48824, USA.
J Chem Phys. 2017 May 7;146(17):174113. doi: 10.1063/1.4979844.
We recently developed an algorithm to compute response properties for the state-averaged complete active space self-consistent field method (SA-CASSCF) that capitalized on sparsity in the atomic orbital basis. Our original algorithm was limited to treating small to moderate sized active spaces, but the recent development of graphical processing unit (GPU) based direct-configuration interaction algorithms provides an opportunity to extend this to large active spaces. We present here a direct-compatible version of the coupled perturbed equations, enabling us to compute response properties for systems treated with arbitrary active spaces (subject to available memory and computation time). This work demonstrates that the computationally demanding portions of the SA-CASSCF method can be formulated in terms of seven fundamental operations, including Coulomb and exchange matrix builds and their derivatives, as well as, generalized one- and two-particle density matrix and σ vector constructions. As in our previous work, this algorithm exhibits low computational scaling and is accelerated by the use of GPUs, making possible optimizations and nonadiabatic dynamics on systems with O(1000) basis functions and O(100) atoms, respectively.
我们最近开发了一种算法，用于计算状态平均完全活性空间自洽场方法（SA-CASSCF）的响应性质，该算法利用了原子轨道基的稀疏性。我们最初的算法仅限于处理小到中等大小的活性空间，但最近图形处理单元（GPU）的直接配置相互作用算法的发展提供了一个机会，可以将其扩展到更大的活性空间。我们在这里提出了耦合微扰方程的直接兼容版本，使我们能够为使用任意活性空间（受可用内存和计算时间限制）处理的系统计算响应性质。这项工作表明，SA-CASSCF 方法中计算密集的部分可以用七个基本操作来表示，包括库仑和交换矩阵的构建及其导数，以及广义单粒子和双粒子密度矩阵和 σ 向量的构建。与我们之前的工作一样，该算法的计算规模较低，并且通过使用 GPU 加速，使得在具有 O(1000)个基函数和 O(100)个原子的系统上进行优化和非绝热动力学成为可能。
