[gmx-users] Free energy calculations with BAR and TI

[Ignacio Fernández Galván]

Hi all,

Can I use the same simulations (with delta_lambda=0, init_lambda and foreign_lambda) for TI and BAR calculations? I guess that boils down to whether the simulations with foreign_lambda are in equilibrium with the init_lambda, or they are some sort of hybrid ensemble between the different lambdas.

Whatever the answer, I have another problem. I tried a BAR calculation and got this message with g_bar:

Fatal error:
Temperature in file 0.1.xvg different from earlier files or setting

But the temperatures are all the same:

$ grep 'T =' ?.?.xvg
0.0.xvg:@ subtitle "T = 298.15 (K), \xl\f{} = 0"
0.1.xvg:@ subtitle "T = 298.15 (K), \xl\f{} = 0.1"
0.2.xvg:@ subtitle "T = 298.15 (K), \xl\f{} = 0.2"
0.3.xvg:@ subtitle "T = 298.15 (K), \xl\f{} = 0.3"
0.4.xvg:@ subtitle "T = 298.15 (K), \xl\f{} = 0.4"
0.5.xvg:@ subtitle "T = 298.15 (K), \xl\f{} = 0.5"
0.6.xvg:@ subtitle "T = 298.15 (K), \xl\f{} = 0.6"
0.7.xvg:@ subtitle "T = 298.15 (K), \xl\f{} = 0.7"
0.8.xvg:@ subtitle "T = 298.15 (K), \xl\f{} = 0.8"
0.9.xvg:@ subtitle "T = 298.15 (K), \xl\f{} = 0.9"
1.0.xvg:@ subtitle "T = 298.15 (K), \xl\f{} = 1"

Is this maybe due to some numerical rounding error?

Thanks
Ignacio