Use of compute reduce to Average values of the radius of gyration vector


I would like to calculate the average of the radius of gyration of the polymer chains ( contained in the group poly) in my system (which also contains cross-linker molecules).

1). compute 1 poly gyration/molecule

2). compute rgave poly reduce ave c_1

I understand that the first command computes a global vector of the radius of gyration with length of Nmolecules. I am trying to use the compute reduce command to average the values in the vector over all the chains but it gives me the following error:

ERROR: Compute reduce compute calculates global values

I understand that the “compute reduce” documentation specifically requires per atom or local quantities as input in the newer version of LAMMPS. Is there a different way of obtaining averaged values for the radius of gyration vector?

Thank you for your help.

Varun Ullal.

That functionality of compute reduce for global vectors has
been replaced with the sum(), ave(), etc options in variables,
noted on the variable doc page as "special functions".