What does the first number in each line mean when the checkrelax program is used, and how this number is obtained?
Thank you!
It measures the magnitude of the strain that need to be applied to the unit cell of str.cell to get the unit cell of str_relax.out, neglecting (i) isotropic scaling and (ii) rigid rotation. The number reported is the sqrt of the sum of each element of the strain tensor squared.
Thanks for your reply. Could you please let me know which c++ file I should look into to find our how the strain is calculated?
The script checkrelax calls the code checkcell. So look into checkcell.c++ it’s very short.