Dear all,

I am using ‘compute msd’ command to get diffusion coefficient. What I am interested is the fourth element of msd array. Therefor, I used the following command:

group tenlipids molecule 1:1:10

compute 1 tenlipids msd

fix 1 tenlipids ave/time 1 1 5 c_1[4] file msd.dumpfile mode vector

However, it gives an error of ‘Fix ave/time compute does not calculate an array’.

By changing c_1[4] to c_1, I got a format like:

476235 4 |

1 1.22065 |

2 0.918748 |

3 1.60794 |

**4 3.74734** |

476240 4 |

1 1.01229 |

2 1.13773 |

3 1.62627 |

**4 3.77629** |

Is there a way by using lammps only without using matlab or c++ to post-processing the data to get the fourth array? I’m not sure why the lammps command gives error.

Thanks,

Sean!

Dear all,

I am using 'compute msd' command to get diffusion coefficient. What I am

interested is the fourth element of msd array. Therefor, I used the

following command:

group tenlipids molecule 1:1:10

compute 1 tenlipids msd

fix 1 tenlipids ave/time 1 1 5 c_1[4] file msd.dumpfile mode vector

However, it gives an error of 'Fix ave/time compute does not calculate

an array'.

By changing c_1[4] to c_1, I got a format like:

476235 4 1 1.22065 2 0.918748 3 1.60794 *4 3.74734* 476240 4 1

1.01229 2 1.13773 3 1.62627 *4 3.77629* Is there a way by using lammps

only without using matlab or c++ to post-processing the data to get the

fourth array? I'm not sure why the lammps command gives error.

you get the error because you use "mode vector". you need "mode scalar",

i.e. the default.

axel.