forked from lijiext/lammps
43 lines
1.5 KiB
HTML
43 lines
1.5 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
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<HTML>
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<HEAD>
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<META NAME="Generator" CONTENT="Cosmo Create 1.0.3">
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</HEAD>
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<BODY>
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<H2>
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LAMMPS Deficiencies</H2>
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<P>
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<A HREF="README.html">Return</A> to top-level of LAMMPS documentation.</P>
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<P>
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This is a brief list of features lacking in the current version of
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LAMMPS. Some of these deficiencies are because of lack of
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time/interest; others are just hard!</P>
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<UL>
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<LI>
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The calculation of pressure does not include a long-range Van der Waals
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correction. This would be a constant for constant volume simulations
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but is a source of error for constant pressure simulations where
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the box-size varies dynamically.
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<LI>
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The smoothed Coulomb style cannot be used with class 2 force fields.
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<LI>
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The minimizer does not work with constant pressure conditions, nor
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for some kinds of fixes (constraints).
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<LI>
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No support for non-rectilinear boxes (e.g. Parinello-Rahman
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pressure control).
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<LI>
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SHAKE fixes cannot be combined with rREPSA.
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<LI>
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In the current F90 version of LAMMPS, Ewald computations are 2x slower
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on some machines than they were in the earlier F77 version. This is
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probably because of F90 compiler treatment of allocatable arrays. This
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slowdown is not an issue with PPPM, which is more commonly used anyway.
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<LI>
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LAMMPS uses a spatial-decomposition of the simulation domain, but no
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other load-balancing -- thus some geometries or density fluctuations can
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lead to load imbalance on a parallel machine.
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</UL>
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</BODY>
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</HTML>
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