Installation Guide

Prerequisites

The following modules are needed to be able to compile FLOSIC:

• OpenBLAS

• LAPACK

The code is accessible from a GitHub repository. To download the latest version, use a git command as follows:

git clone https://github.com/FLOSIC/PublicRelease_2020.git

Compilation

Once you have obtained the code from the repository, go to the directory containing the source files. You will need to edit three blocks of lines in the makefile to suit your needs.

Note

If you have not modified a Makefile before - no worries! You only have to switch a few variables.

First block: parallel or serial

# set Y or N
# Parallel compilation
MPI=Y
# Group calculation
GROUP=N

In this block, the user specifies whether the compilation will be the parallel (MPI=Y) or serial (MPI=N) version of the code. When using a parallel version, the user can choose to use a multi-level parallel scheme by setting GROUP=Y: this parallelizes over the orbitals in calculating SIC potentials, and also over the grid points. This option can deliver a greater speed up than the single-level parallel scheme, but it is not recommended for new users.

When GROUP=Y, the user should edit the “igroup” file in the run directory. This file should contain an integer that is an even divisor of the number of orbitals. For example, for 100 orbitals, igroup might be 10 or 20, but not 15.

Second block: compiler choices

# COMPILERS
CC = gcc
FC = mpif90
FFF = mpif90
# COMPILER FLAGS
CFLAGS = -O3
FFLAGS = -fbounds-check -std=legacy
LFLAGS = -fbounds-check -std=legacy

The second block is to specify the compilers and their flags used during the compilation. A number of routines require static allocation of arrays. The code needs to be compiled for appropriate array sizes for the system under study and these static parameters are listed in the file called PARAMA2.

Note

Newer versions of Ubuntu require the use of the std=legacy flag in order to run.

An example of the compilers used for NERSC is below.

CC = cc
FC = ftn
FFF = ftn

Third block: linking options

$(FFF) $(LFLAGS) $(OBJ) -o $(BIN) -llapack -lblas $(LIBS)

This block specifies the libraries used for linking, where it is recommended to use optimized BLAS and LPACK libraries if they are available on your platform to achieve the best performance.

Edit PARAMA2 for static parameters :

Parameter | Brief explanation
MAX_PTS	maximum size of integration grid
MX_SPH	needed to generate the integration mesh
MAXUNSYM	maximum number of orbitals for an atomic basis
NDH	maximum total basis set size
NDH_TOT	maximum number of Hamiltonian matrix elements
MAX_OCC	maximum number of occupied states
MX_GRP	maximum size of symmetry group

An example for serial compilation on a laptop (in this case a mac) is shown below.

First block: Compile the serial version

MPI=N
GROUP=N

Second block: use gcc and gfortran compilers

#COMPILERS
CC = gcc
FC = gfortran
FFF = gfortran

#COMPILER FLAGS
CFLAGS = -O3
FFLAGS = -O3
LFLAGS = -O3

Third block: Use the linking options under Fedora (Quantum/Luis local)

$(FFF) $(LFLAGS) $(OBJ) -o $(BIN) $(PCM_LIBS) $(EFP_LIB) -llapack -lblas $(LIBS)

Use the make command on the command line to compile FLOSIC. If the compilation was successful, an executable file titled nrlmol_exe will be created.

Additional Support

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