# Coordinate descent full configuration interaction

## TL;DR

The paper introduces CDFCI, an efficient coordinate descent algorithm for full configuration interaction calculations, achieving high accuracy in static and dynamic correlation energy computations for complex molecules.

## Contribution

It presents a novel coordinate descent approach with a deterministic compression strategy for FCI, improving efficiency and accuracy in electronic structure calculations.

## Key findings

- Accurately computes nitrogen dimer binding curve with 10^{-3} mHa precision.
- Demonstrates efficiency and accuracy on chromium dimer, achieving state-of-the-art results.
- Produces reliable variational energies for strongly correlated systems.

## Abstract

We develop an efficient algorithm, coordinate descent FCI (CDFCI), for the electronic structure ground state calculation in the configuration interaction framework. CDFCI solves an unconstrained non-convex optimization problem, which is a reformulation of the full configuration interaction eigenvalue problem, via an adaptive coordinate descent method with a deterministic compression strategy. CDFCI captures and updates appreciative determinants with different frequencies proportional to their importance. We show that CDFCI produces accurate variational energy for both static and dynamic correlation by benchmarking the binding curve of nitrogen dimer in the cc-pVDZ basis with $10^{-3}$ mHa accuracy. We also demonstrate the efficiency and accuracy of CDFCI for strongly correlated chromium dimer in the Ahlrichs VDZ basis and produces state-of-the-art variational energy.