Semistochastic Heat-Bath Configuration Interaction Method: Selected Configuration Interaction with Semistochastic Perturbation Theory

Semistochastic projector Monte Carlo method.

We introduce a semistochastic implementation of the power method to compute, for very large matrices, the dominant eigenvalue and expectation values involving the corresponding eigenvector. The method is semistochastic in that the matrix multiplication is partially implemented numerically exactly and partially stochastically with respect to expectation values only. Compared to a fully stochasti...

Semistochastic Quadratic Bound Methods

Partition functions arise in a variety of settings, including conditional random fields, logistic regression, and latent gaussian models. In this paper, we consider semistochastic quadratic bound (SQB) methods for maximum likelihood estimation based on partition function optimization. Batch methods based on the quadratic bound were recently proposed for this class of problems, and performed fav...

Constrained Density-Functional Theory—Configuration Interaction

In this thesis, I implemented a method for performing electronic structure calculations, “Constrained Density Functional Theory–Configuration Interaction” (CDFT-CI), which builds upon the computational strengths of Density Functional Theory and improves upon it by including higher level treatments of electronic correlation which are not readily available in Density-Functional Theory but are a k...

An Introduction to Configuration Interaction Theory

Analysis of Coupled Cluster and Quadratic Configuration Interaction Theory in Terms of Sixth-Order Perturbation Theory

The energy at sixth-order Mnller-Plesset (MP6) perturbation theory is given and dissected into 36 sizeconsistent energy contributions resulting from single ( S ) , double ( D), triple (T ), quadruple ( Q ) , pentuple (P), and hextuple (H) excitations. It is shown that MP6 is an O ( N 9 ) method, but less costly approximations to M P ~ are possible. M P ~ is used to analyze and compare coupled c...