How To Install chemps2 on Ubuntu 22.04

In this tutorial we learn how to install chemps2 on Ubuntu 22.04. chemps2 is Executable to call libchemps2-3 from the command line

Introduction

In this tutorial we learn how to install chemps2 on Ubuntu 22.04.

What is chemps2

chemps2 is:

chemps2 is a scientific library which contains a spin-adapted implementation of the density matrix renormalization group (DMRG) for ab initio quantum chemistry. This wavefunction method allows one to obtain numerical accuracy in active spaces beyond the capabilities of full configuration interaction (FCI), and allows one to extract the 2-, 3-, and 4-particle reduced density matrices (2-, 3- and 4-RDM) of the active space.

For general active spaces up to 40 electrons in 40 orbitals can be handled with DMRG, and for one-dimensional active spaces up to 100 electrons in 100 orbitals. The 2-RDM of these active spaces can also be easily extracted, while the 3- and 4-RDM are limited to about 28 orbitals.

When the active space size becomes prohibitively expensive for FCI, DMRG can be used to replace the FCI solver in the complete active space self consistent field (CASSCF) method and the corresponding complete active space second order perturbation theory (CASPT2). The corresponding methods are called DMRG-SCF and DMRG-CASPT2, respectively. For DMRG-SCF the active space 2-RDM is required, and for DMRG-CASPT2 the active space 4-RDM.

This package installs the executable which parses Hamiltonians in fcidump format, performs DMRG-SCF and DMRG-CASPT2 calculations as specified by the user.

There are three methods to install chemps2 on Ubuntu 22.04. We can use apt-get, apt and aptitude. In the following sections we will describe each method. You can choose one of them.

Install chemps2 Using apt-get

Update apt database with apt-get using the following command.

sudo apt-get update

After updating apt database, We can install chemps2 using apt-get by running the following command:

sudo apt-get -y install chemps2

Install chemps2 Using apt

Update apt database with apt using the following command.

sudo apt update

After updating apt database, We can install chemps2 using apt by running the following command:

sudo apt -y install chemps2

Install chemps2 Using aptitude

If you want to follow this method, you might need to install aptitude first since aptitude is usually not installed by default on Ubuntu. Update apt database with aptitude using the following command.

sudo aptitude update

After updating apt database, We can install chemps2 using aptitude by running the following command:

sudo aptitude -y install chemps2

How To Uninstall chemps2 on Ubuntu 22.04

To uninstall only the chemps2 package we can use the following command:

sudo apt-get remove chemps2

Uninstall chemps2 And Its Dependencies

To uninstall chemps2 and its dependencies that are no longer needed by Ubuntu 22.04, we can use the command below:

sudo apt-get -y autoremove chemps2

Remove chemps2 Configurations and Data

To remove chemps2 configuration and data from Ubuntu 22.04 we can use the following command:

sudo apt-get -y purge chemps2

Remove chemps2 configuration, data, and all of its dependencies

We can use the following command to remove chemps2 configurations, data and all of its dependencies, we can use the following command:

sudo apt-get -y autoremove --purge chemps2

References

Summary

In this tutorial we learn how to install chemps2 package on Ubuntu 22.04 using different package management tools: apt, apt-get and aptitude.