Introduction

In my previous post, I explained how to build VASP using the GNU compilers. Here, I will show you how you can build VASP using the Intel Compilers. In principle, the Intel Compilers should give better performance for VASP on Intel processors.

Step 0: Install the Intel Compilers

Install the Intel Compiler Suite in /opt/intel (this is the default setting). Please refer to the installation instructions given by Intel.

Step 1: Load the Intel Compilers

source /opt/intel/composer_xe_2013_sp1/bin/compilervars.sh intel64

Step 2: Compile the Intel FFTW wrappers

cd /opt/intel/composer_xe_2013_sp1/mkl/interfaces/fftw3xf
make libintel64

Step 3: Compile the VASP libraries

tar -xvzf vasp.4.lib.tar.gz
cd vasp.4.lib
cp makefile.linux_ifc_P4 Makefile

and change the file so that FC is linking to ifort

.SUFFIXES: .inc .f .F
#-----------------------------------------------------------------------
# Makefile for Portland Group F90/HPF compiler
# the makefile was tested only under Linux on Intel platforms
# however it might work on other platforms as well
#
# this release of vasp.4.lib contains lapack v2.0
# this can be compiled with pgf90 compiler if the option -O1 is used
#
# Mind: one user reported that he had to copy preclib.F diolib.F
#  dlexlib.F and drdatab.F to the directory vasp.4.4, compile the files
#  there and link them directly  into vasp
#  for no obvious reason these files could not be linked from the library
#
#-----------------------------------------------------------------------

# C-preprocessor
CPP     = gcc -E -P -C $*.F >$*.f
FC=ifort 

CFLAGS = -O
FFLAGS = -O0 -FI
FREE   =  -FR

DOBJ =  preclib.o timing_.o derrf_.o dclock_.o  diolib.o dlexlib.o drdatab.o

and type

make

Step 4: Compile VASP

source /opt/intel/impi/4.1.1.036/bin64/mpivars.sh
tar -xvzf vasp.4.6.tar.gz
cd vasp.4.6
cp makefile.linux_ifc_P4 Makefile

Alter the Makefile on the following points

and finally run make

make

when you get this error

mpif77 -fc=ifort -FR -names lowercase -assume byterecl  -O3 -xAVX  -c fftmpiw.f90
fftmpiw.f90(55): error #5102: Cannot open include file 'fftw3.f'
      include 'fftw3.f'
--------------^
fftmpiw.f90(89): error #5102: Cannot open include file 'fftw3.f'
      include 'fftw3.f'
--------------^
fftmpiw.f90(110): error #5102: Cannot open include file 'fftw3.f'
      include 'fftw3.f'
--------------^
fftmpiw.f90(220): error #5102: Cannot open include file 'fftw3.f'
      include 'fftw3.f'
--------------^
compilation aborted for fftmpiw.f90 (code 1)
make: *** [fftmpiw.o] Error 1

copy the header file

cp /opt/intel/mkl/include/fftw/fftw3.f .

and run make again

make

Step 5: Testing our compilation and comparing against the GNU compilation

We have used three different models to check the computational efficiency of the Intel Compilations versus that of the GNU compilation:

• A single CO molecule in a large box (gamma-point calculation)
• A bulk Cu system
• A Fe₅C₂ (Hagg carbide) system

The results are the following:

Interestingly, the Intel compiler does not give significantly different result for the gamma-point calculation (CO molecule). However, the speed improvement for the other calculations is roughly 30%!