Added the UFM files (doc/src - lib/gpu - src)

doc/src/Eqs/pair_ufm.tex

@@ -0,0 +1,14 @@
+\documentclass[12pt]{article}
+
+\begin{document}
+
+$$
+	E = -\varepsilon\, \ln{\left[1-\exp{\left(-r^{2}/\sigma^{2}\right)}\right]} \qquad  r < r_c
+$$
+
+$$
+  \varepsilon = p\,k_B\,T
+$$
+
+\end{document}
+

doc/src/pair_ufm.txt

@@ -0,0 +1,135 @@
+"LAMMPS WWW Site"_lws - "LAMMPS Documentation"_ld - "LAMMPS Commands"_lc :c
+
+:link(lws,http://lammps.sandia.gov)
+:link(ld,Manual.html)
+:link(lc,Section_commands.html#comm)
+
+:line
+
+pair_style ufm command :h3
+pair_style ufm/gpu command :h3
+pair_style ufm/omp command :h3
+pair_style ufm/opt command :h3
+
+[Syntax:]
+
+pair_style ufm cutoff :pre
+
+cutoff = global cutoff for {ufm} interactions (distance units) :ul
+
+[Examples:]
+
+pair_style ufm 4.0
+pair_coeff 1 1 100.0 1.0 2.5
+pair_coeff * * 100.0 1.0 :pre
+
+
+pair_style ufm 4.0
+pair_coeff * * 10.0 1.0
+variable prefactor equal ramp(10,100)
+fix 1 all adapt 1 pair ufm epsilon * * v_prefactor :pre
+
+[Description:]
+
+Style {ufm} computes pairwise interactions using the Uhlenbeck-Ford model (UFM) potential "(Paula Leite2016)"_#PL2 which is given by
+
+:c,image(Eqs/pair_ufm.jpg)
+
+where rc is the cutoff, sigma is a distance-scale and epsilon is an energy-scale, i.e., a product of Boltzmann constant kB, temperature T and the Uhlenbeck-Ford p-parameter which is responsible
+to control the softness of the interactions "(Paula Leite2017)"_#PL1.
+This model is useful as a reference system for fluid-phase free-energy calculations "(Paula Leite2016)"_#PL2. 
+
+The following coefficients must be defined for each pair of atom types
+via the "pair_coeff"_pair_coeff.html command as in the examples above,
+or in the data file or restart files read by the
+"read_data"_read_data.html or "read_restart"_read_restart.html
+commands, or by mixing as described below:
+
+epsilon (energy units)
+sigma (distance units)
+cutoff (distance units) :ul
+
+The last coefficient is optional.  If not specified, the global {ufm}
+cutoff is used.
+
+
+The "fix adapt"_fix_adapt.html command can be used to vary epsilon and sigma for this pair style over the course of a simulation, in which case
+pair_coeff settings for epsilon and sigma must still be specified, but will be
+overridden.  For example these commands will vary the prefactor epsilon for
+all pairwise interactions from 10.0 at the beginning to 100.0 at the end
+of a run:
+
+variable prefactor equal ramp(10,100)
+fix 1 all adapt 1 pair ufm epsilon * * v_prefactor :pre
+
+NOTE: The thermodynamic integration procedure can be performed with this potential using "fix adapt"_fix_adapt.html. This command will rescale the force on each atom by varying a scale variable, which always starts with value 1.0. The syntax is the same described above, however, changing epsilon to scale. A detailed explanation of how to use this command and perform nonequilibrium thermodynamic integration in LAMMPS is given in the paper by "(Freitas)"_#Freitas.
+
+:line
+
+Styles with a {gpu}, {intel}, {kk}, {omp}, or {opt} suffix are
+functionally the same as the corresponding style without the suffix.
+They have been optimized to run faster, depending on your available
+hardware, as discussed in "Section 5"_Section_accelerate.html
+of the manual.  The accelerated styles take the same arguments and
+should produce the same results, except for round-off and precision
+issues.
+
+These accelerated styles are part of the GPU, USER-INTEL, KOKKOS,
+USER-OMP and OPT packages, respectively.  They are only enabled if
+LAMMPS was built with those packages.  See the "Making
+LAMMPS"_Section_start.html#start_3 section for more info.
+
+You can specify the accelerated styles explicitly in your input script
+by including their suffix, or you can use the "-suffix command-line
+switch"_Section_start.html#start_6 when you invoke LAMMPS, or you can
+use the "suffix"_suffix.html command in your input script.
+
+See "Section 5"_Section_accelerate.html of the manual for
+more instructions on how to use the accelerated styles effectively.
+
+:line
+
+[Mixing, shift, table, tail correction, restart, rRESPA info]:
+
+For atom type pairs I,J and I != J, the A coefficient and cutoff
+distance for this pair style can be mixed.  A is always mixed via a
+{geometric} rule.  The cutoff is mixed according to the pair_modify
+mix value.  The default mix value is {geometric}.  See the
+"pair_modify" command for details.
+
+This pair style support the "pair_modify"_pair_modify.html shift option for the energy of the pair interaction.
+
+The "pair_modify"_pair_modify.html table and tail are not relevant for this
+pair style.
+
+This pair style does not support the "pair_modify"_pair_modify.html tail option for adding long-range tail corrections to energy and pressure.
+
+This pair style writes its information to "binary restart
+files"_restart.html, so pair_style and pair_coeff commands do not need
+to be specified in an input script that reads a restart file.
+
+This pair style can only be used via the {pair} keyword of the
+"run_style respa"_run_style.html command.  It does not support the
+{inner}, {middle}, {outer} keywords.
+
+:line
+
+[Restrictions:] none
+
+[Related commands:]
+
+"pair_coeff"_pair_coeff.html, "fix adapt"_fix_adapt.html
+
+[Default:] none
+
+
+:link(PL1)
+[(Paula Leite2017)] Paula Leite, Santos-Florez, and de Koning, Phys Rev E, 96,
+32115 (2017).
+
+:link(PL2)
+[(Paula Leite2016)] Paula Leite , Freitas, Azevedo, and de Koning, J Chem Phys, 126,
+044509 (2016).
+
+:link(Freitas)
+[(Freitas)] Freitas, Asta, and de Koning, Computational Materials Science, 112, 333 (2016).