How To Install python3-chemps2 on Ubuntu 18.04
Introduction
In this tutorial we learn how to install python3-chemps2 on Ubuntu 18.04.
What is python3-chemps2
python3-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 library for Python 3.
There are three methods to install python3-chemps2 on Ubuntu 18.04. We can use apt-get, apt and aptitude. In the following sections we will describe each method. You can choose one of them.
Install python3-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 python3-chemps2 using apt-get by running the following command:
sudo apt-get -y install python3-chemps2
Install python3-chemps2 Using apt
Update apt database with apt using the following command.
sudo apt update
After updating apt database, We can install python3-chemps2 using apt by running the following command:
sudo apt -y install python3-chemps2
Install python3-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 python3-chemps2 using aptitude by running the following command:
sudo aptitude -y install python3-chemps2
How To Uninstall python3-chemps2 on Ubuntu 18.04
To uninstall only the python3-chemps2 package we can use the following command:
sudo apt-get remove python3-chemps2
Uninstall python3-chemps2 And Its Dependencies
To uninstall python3-chemps2 and its dependencies that are no longer needed by Ubuntu 18.04, we can use the command below:
sudo apt-get -y autoremove python3-chemps2
Remove python3-chemps2 Configurations and Data
To remove python3-chemps2 configuration and data from Ubuntu 18.04 we can use the following command:
sudo apt-get -y purge python3-chemps2
Remove python3-chemps2 configuration, data, and all of its dependencies
We can use the following command to remove python3-chemps2 configurations, data and all of its dependencies, we can use the following command:
sudo apt-get -y autoremove --purge python3-chemps2
References
Summary
In this tutorial we learn how to install python3-chemps2 package on Ubuntu 18.04 using different package management tools: apt, apt-get and aptitude.
