MacroModel Reference Manual - ISP

Chapter 4: Operation Codes20 Use TNCG method if the number of unfixed atoms is less than 1000 and solvation isemployed; otherwise use PRCG. Sets arg2 to 1.arg2Line searching protocol0 Default line searching1 For SD or FMNR or LBFGS, turns on line searching. Although LBFGS can be usedwith line search, it is not recommended in the current implementation.For PRCG, selects 3-point line searcher (use with problematic structures)For TNCG, selects original line searcher (try for problematic structures)arg3arg4arg5Maximum number of iterationsThe default of 0 iterations may be used when the semantics of surrounding commandsrequires a MINI command but it is not desired to actually perform aminimization. When a minimization is run from MacroModel, arg3 is set to 500 bydefault. For PRCG and OSVM minimization methods, some small multiple of 3Nsteps often suffices, where N is the number of atoms in the system being simulated.Energy code (see DEMX)Step-size bufferThis variable, 1.0 by default (1.1 for PRCG), is used to increase or decrease the stepsize during minimization. If arg5>1, then convergence may be accelerated, but theprocedure can also become unstable. If arg5