7th Users' Conference of IT4Innovations

Generating coupled cluster code for modern distributed memory tensor software

30 Oct 2023, 18:00

20m

atrium (IT4Innovations)

User's talk Users' talks Users' Talks III

Speaker

Jan Brandejs (Laboratoire de Chimie et Physique Quantiques, CNRS)

Description

The goal of this project is to design a set of software tools for elegant development of relativistic coupled clusters methods.

Figure 1: The workflow scheme of the tenpi toolchain includes a code generator, intermediate optimizer and a unified interface towards tensor libraries. Fig. from [3].

Modern computer architectures are composed of heterogeneous processing and memory hierarchies. Data movement cost often dominates the cost of computation and only a fraction of peak CPU/GPU power is used. Despite this, most software still uses programming systems lacking any reasoning about the placement and movement of data.

Unlike BLAS for matrix operations, there is no unified tensor interface/library used by the community.
Available distributed memory libraries used for chemical applications are not adapted to heterogeneous architectures.
The tenpi toolchain addresses this problem.

Motto: “Separate science from the computational platform.”

The first application of the tenpi toolchain is on molecular properties as part of the HAMP-vQED project [4].
Studies so far indicate that QED-effects (electron self-energy and vacuum polarization) reduce relativistic effects by about 1%. However, such investigations have been limited to valence properties, since there are currently no reliable tools for general molecules to study the core region, where QED-effects are generated [2].

[2] P. Pyykko, J. F. Stanton, Chemical Reviews 112 (2012) 1.
[3] https://starpu.gitlabpages.inria.fr, visited 2.6.2023
[4] A. Sunaga, M. Salman and Trond Saue, J. Chem. Phys. 157 (2022) 164101.