# Quantum ESPRESSO/PWSCF¶

Quantum ESPRESSO is an integrated suite of computer codes for electronic structure calculations and materials modeling at the nanoscale. It builds on the electronic structure codes PWscf, PHONON, CP90, FPMD, and Wannier. It is based on density-functional theory, plane waves, and pseudopotentials (both norm-conserving and ultrasoft).

## Using Quantum ESPRESSO at NERSC¶

NERSC provides modules with precompiled Quantum ESPRESSO installations.

Available versions can be found by running:

nersc$module avail espresso  and the specific version is loaded via nersc$ module load espresso/<version>


### Examples¶

For all routines except pw.x, run QE in full MPI mode as there is currently no efficient OpenMP implementation available.

Cori Haswell

#!/bin/bash
#SBATCH -qos=regular
#SBATCH --nodes=2
#SBATCH -C haswell
#SBATCH -t 02:00:00
#SBATCH -J my_job

srun ph.x -input test.in


Warning

Pay close attention to the explicit setting of OMP_NUM_THREADS=1 when running in pure MPI mode. This is optimal when intending to run with only MPI tasks.

#### hybrid DFT¶

We have optimized the hybrid DFT calculations in Quantum ESPRESSO (pw.x). These changes are described in our Quantum ESPRESSO case study and available in the espresso/6.1 module we provide.

The following scripts provides the best pw.x performance for hybrid functional calculations:

Cori Haswell

#!/bin/bash
#SBATCH --qos=regular
#SBATCH --nodes=2
#SBATCH -C haswell
#SBATCH -t 02:00:00
#SBATCH -J my_job

srun --cpu-bind=cores pw.x -nbgrp 8 -input test.in


Cori KNL

#!/bin/bash
#SBATCH --qos=regular
#SBATCH --nodes=2
#SBATCH -t 02:00:00
#SBATCH -J my_job

srun --cpu-bind=cores pw.x -nbgrp 8 -input test.in


Tip

For band-group parallelization, it is recommended to run one band group per MPI rank. However, please keep in mind that it is not possible to use more band-groups than there are bands in your system, so adjust the number accordingly if issues are encountered.

Note

The new implementation is much more efficient, so you might be able to use much fewer nodes and still get the solution within the same wallclock time.

## Compilation Instructions¶

Some users may be interested in tweaking the Quantum ESPRESSO build parameters and building QE themselves. Our build instructions for the QE module are listed below. The following procedure was used to build Quantum ESPRESSO versions >5.4 on Cori. In the root QE directory:

nersc$./configure nersc$ cp /usr/common/software/espresso/<version>/<arch>/<comp>/make.inc .
nersc\$ make <application-name, e.g. pw>


where <version> specifies the version, <arch> the architecture (usually hsw or knl for Haswell and KNL respectively) and <comp> the compiler (usually gnu or intel).

Note

Not all versions are available for all architectures or compilers.