Computational Efficiency

Parallel scaling for Diamondoid_octahedral (148 atoms, red line) and Vitamin E (81 atoms, blue line)

Parallel scaling for vitamin E molecule (cc-pVDZ, 81 atoms, 684 basis functions)

  • Resolution-of-the-Identity Algorithms for SCF and Post-SCF Calculations:

    • occ-RI-K algorithm for Hartree-Fock exchange;

    • RI-SCF gradient;

    • I-MP2, SCS-MP2, SOSMP2 methods;

    • RI-CCSD and RI-EOM energies and gradients.

  • Fast Algorithms for DFT Calculations:

    • Algorithms for Coulomb (Continuous Fast Multipole Method, J engine, Fourier Transform Coulomb, Quantum Ewald Mesh);

    • Algorithms for Hartree-Fock exchange (LinK, ARIK) and numerical integration (mrXC).

  • Fast Algorithms for Perturbation Theory Calculations:

    • Fast integral transformations, RI approximation, scaling of different spin components, Laplace transform, dual basis extrapolation, and the use of localized orbitals.
  • Fast Algorithms for Coupled-Cluster Calculations:

    • Enhanced by a modern tensor library, RI approximation, Cholesky decomposition, single-precision execution, frozen natural orbitals.
  • Efficient Implementation on Shared-Memory Multicore Machines; GPU acceleration via BrianQC module; Cloud-Enabled.