[gmx-users] installing error

[banijamali_fs]

Hi there, I'm installing gromacs with these series of commands,

sudo apt-get update

sudo apt-get upgrade

sudo apt-get install cmake

cmake --version

sudo apt-get install build-essential

pwd

cd Downloads/

wget http://gerrit.gromacs.org/download/regressiontests-5.1.1.tar.gz

tar xvzf regressiontests-5.1.1.tar.gz

sudo apt-get install libfftw3-dev

but when I want to run this " sudo apt-get install libfftw3-dev"
command, I receive this error,

Reading package lists... Done
Building dependency tree 
Reading state information... Done
Package libfftw3-dev is not available, but is referred to by another
package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'libfftw3-dev' has no installation candidate

I don't know what should I do? please help me with my error