Install a parallel version of lammps on ubuntu based systems.

lammps_parallel.sh

#!/bin/bash
### Lammps parallel install

# Assign user name
read -p "Enter your user name: " UserName

# Install required packages
apt-get update
apt-get -y upgrade
apt-get -y install build-essential openmpi-bin openmpi-doc libopenmpi-dev fftw2 fftw-dev

# Check/remove lammps.tar.gz
if [ -f ~/Downloads/lammps.tar.gz ]
	then
		rm ~/Downloads/lammps.tar.gz
fi

# Downloads lammps.tar.gz
sudo -u $UserName wget -P ~/Downloads http://lammps.sandia.gov/tars/lammps.tar.gz

cd ~/Downloads
sudo -u $UserName tar xzf ~/Downloads/lammps.tar.gz
cd lammps-*
cd src
cd MAKE
sudo -u $UserName cp Makefile.mpi Makefile.mint
sudo -u $UserName sed -i -e 's/# openmpi/ # mint = Linux Mint, mpic++, OpenMPI-1.1, FFTW2/g' Makefile.mint
sudo -u $UserName sed -i -e 's/-DFFT_FFTW3/-DFFT_FFTW2/g' Makefile.mint
cd ..
sudo -u $UserName make yes-kspace
sudo -u $UserName make yes-user-phonon
sudo -u $UserName make mode=lib mint
sudo -u $UserName make mode=shlib mint
sudo -u $UserName make mint
 
# Make python library
make install-python

cd ~

It appears lammps is trying to link to fftw3 and not fftw2, the line:
sudo -u $UserName sed -i -e 's/-DFFT_FFTW3/-DFFT_FFTW2/g' Makefile.mint
should text replace any instances of the compilation flag for fftw3 with fftw2. I would check the makefile and see if it is trying to link to fftw3 at
FFT_INC =

The ubuntu repo does have fftw3 but I haven't been able to successfully link lammps to it.