This is part of the drr module
It is only available if you configure PLUMED with ./configure –enable-modules=drr . Furthermore, this feature is still being developed so take care when using it and report any problems on the mailing list.
  • Extract .grad and .count files from the binary output .drrstate
  • Merge windows

The following command will extract .grad and .count files.

plumed drr_tool --extract eabf.drrstate

The following command will merge windows of two .drrstate file, and output the .grad and .count files.

plumed drr_tool --merge win1.drrstate,win2.drrstate

After getting the .grad and .count file, you can do numerical integration by using abf_integrate tool from https://github.com/Colvars/colvars/tree/master/colvartools

abf_integrate eabf.czar.grad
The abf_integrate in colvartools is in kcal/mol, so it may be better to use –units kcal/mol when running drr_tool
Glossary of keywords and components
Compulsory keywords
--units ( default=kj/mol ) the units of energy can be kj/mol, kcal/mol, j/mol, eV or the conversion factor from kj/mol
--help/-h ( default=off ) print this help

( default=off ) Verbose output

--extract Extract drrstate file(s)
--merge Merge eABF windows
--merge_output The output filename of the merged result
--divergence Calculate divergence of gradient field (experimental)