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	LAMMPS Deficiencies</H2>
	<P>
	<A HREF="README.html">Return</A> to top-level of LAMMPS documentation.</P>
	<P>
	This is a brief list of features lacking in the current version of
	LAMMPS. Some of these deficiencies are because of lack of
	time/interest; others are just hard!</P>
	<UL>
	<LI>
	The calculation of pressure does not include a long-range Van der Waals
	correction. This would be a constant for constant volume simulations
	but is a source of error for constant pressure simulations where
	the box-size varies dynamically.
	<LI>
	The smoothed Coulomb style cannot be used with class 2 force fields.
	<LI>
	The minimizer does not work with constant pressure conditions, nor
	for some kinds of fixes (constraints).
	<LI>
	No support for non-rectilinear boxes (e.g. Parinello-Rahman
	pressure control).
	<LI>
	SHAKE fixes cannot be combined with rREPSA.
	<LI>
	In the current F90 version of LAMMPS, Ewald computations are 2x slower
	on some machines than they were in the earlier F77 version. This is
	probably because of F90 compiler treatment of allocatable arrays. This
	slowdown is not an issue with PPPM, which is more commonly used anyway.
	<LI>
	LAMMPS uses a spatial-decomposition of the simulation domain, but no
	other load-balancing -- thus some geometries or density fluctuations can
	lead to load imbalance on a parallel machine.
	</UL>
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