GromacsWarning: angles funct != 1 or 5; unknown functional

[Changji Yin]

Hi guys, 

I need your kind support.

When I calculate the binding energy between protein and ligand with gmx_MMPBSA, a critical error occurred as"GromacsWarning: angles funct != 1 or 5; unknown functional". I dont know how to fix this error.

my operation environment:

Centos 7

gmx_MMPBSA v1.6.1

(env) Python=3.11.4

ST method of gmx_MMPBSA

all my MD results are obtained with Amber03.ff (5 ns in total). Then I select the md.tpr, md.gro, md.xtc, lig.itp,  topol.top and  index.ndx as my input files. (in which md.* is comprise of protein+ligand+water+ions).  when I run gmx_MMPBSA with ST method. a lot of errors are occurred like this picture. Please help me find the reasons.

[marioe911116]

A topology containing those functionals can't be converted to AMBER... this is a typical error when working with GROMOS for example... I think a possible solution would be to ignore those terms (delete them from the topology) and perform the calculation using single trajectory protocol...