/* */ /* CDDL HEADER START */ /* */ /* The contents of this file are subject to the terms of the Common */ /* Development and Distribution License Version 1.0 (the "License"). */ /* */ /* You can obtain a copy of the license at */ /* http://www.opensource.org/licenses/CDDL-1.0. See the License for the */ /* specific language governing permissions and limitations under the License. */ /* */ /* When distributing Covered Code, include this CDDL HEADER in each file and */ /* include the License file in a prominent location with the name */ /* LICENSE.CDDL. If applicable, add the following below this CDDL HEADER, */ /* with the fields enclosed by brackets "[]" replaced with your own */ /* identifying information: */ /* */ /* Portions Copyright (c) [yyyy] [name of copyright owner]. */ /* All rights reserved. */ /* */ /* CDDL HEADER END */ /* */ /* */ /* Portions Copyright (c) 2019, Regents of the University of Minnesota. */ /* All rights reserved. */ /* */ /* Contributors: */ /* Daniel S. Karls */ /* Ellad B. Tadmor */ /* Ryan S. Elliott */ /* */ /* Portions Copyright (c) 2019, Regents of the University of Minnesota. */ /* All rights reserved. */ /* */ /* Contributors: */ /* Dipanjan Ghosh */ /* */ #include /* Model driver for the Biswas-Hamann (BH) potential */ /* */ /* Source: */ /* Biswas R, Hamann DR (1987), */ /* New classical models for silicon structural energies. */ /* Physical Review B 36(12), 6434. doi:10.1103/PhysRevB.36.6434 */ /* */ /* The following flag indicates whether or not to do an explicit check to */ /* determine if the distance between neighbors j and k of atom i in a */ /* three-body computations exceeds the (single) cutoff distance. The check */ /* is skipped if the flag is set to 1, and performed if the flag is set to 0. */ /* This feature is provided for efficiency reasons. */ /* */ #define SKIP_CHECK_ON_RJK 1 /* The following enumeration provides a named index to each element in your */ /* parameter array. The last entry *must* be NUM_PARAMS (by construction by */ /* being at the end of the list, its value will be the number of parameters). */ /* These names will be used in the functions below to unpack and access */ /* parameters. The order of parameters *is* important. It must match the */ /* ordering in the parameter file read in by the model driver. */ /* */ enum PARAMS { PARAM_A1, PARAM_A2, PARAM_B1, PARAM_B2, PARAM_lambda1, PARAM_lambda2, PARAM_alpha1, PARAM_alpha2, PARAM_rc, PARAM_mu, PARAM_rcutoff, NUM_PARAMS }; #include "cluster_aux.inc" /* The following array of strings contains names and descriptions of the */ /* parameters that will be registered in the KIM API object. The number of */ /* entries must match the number of PARAM_* lines above, and the order must */ /* correspond to the ordering above. */ /* */ static char const * const param_strings[][2] = {{"A1", "Amplitude of the pairwise interaction function"}, {"A2", "Another amplitude of the pairwise interaction function"}, {"B1", "Amplitude of the three-body term"}, {"B2", "Another amplitude of the three-body term"}, {"lambda1", "Another exponent in the pairwise interaction"}, {"lambda2", "Exponent in the pairwise interaction"}, {"alpha1", "Exponent in the three-body term"}, {"alpha2", "Another exponent in the three-body term"}, {"rc", "Parameter in cutoff function"}, {"mu", "Scale in cutoff function"}, {"rcutoff", "Influence distance"}}; /* The following two variables define the base unit system required to be */ /* used by the parameter file. */ /* */ static KIM_LengthUnit const * const length_unit = &KIM_LENGTH_UNIT_A; static KIM_EnergyUnit const * const energy_unit = &KIM_ENERGY_UNIT_eV; /* The following array of double precision values define the unit */ /* exponents for each parameter. The first number is the length exponent */ /* and the second number is the energy exponent. The number of entries must */ /* match the number of PARAM_* lines above, and the order must correspond */ /* to the ordering above. Use two zeros for unitless parameters. */ /* */ static double const param_units[][2] = {{0.0, 1.0}, /* A1 */ {0.0, 1.0}, /* A2 */ {0.0, 1.0}, /* B1 */ {0.0, 1.0}, /* B2 */ {-2.0, 0.0}, /* lambda1 */ {-2.0, 0.0}, /* lambda2 */ {-2.0, 0.0}, /* alpha1 */ {-2.0, 0.0}, /* alpha2 */ {1.0, 0.0}, /* rc */ {1.0, 0.0}, /* mu */ {1.0, 0.0}}; /* rcutoff */ static double get_influence_distance(double const * const params) { /*double const a = params[PARAM_a];*/ /*double const sigma = params[PARAM_sigma];*/ double const rcutoff = params[PARAM_rcutoff]; return rcutoff; } /* Calculate two-body energy phi2(r) and its derivative w.r.t. Rij */ static void calc_phi2_dphi2(double const * const params, double const Rij, double * const phi2, double * const dphi2_dRij) { /* Unpack parameters */ /*double const epsilon = params[PARAM_epsilon]; */ /*double const sigma = params[PARAM_sigma]; */ double f2val; double df2_dRij; if (dphi2_dRij != NULL) { f2_df2(params, Rij, &f2val, &df2_dRij); *phi2 = f2val; *dphi2_dRij = df2_dRij; } else { f2_df2(params, Rij, &f2val, NULL); *phi2 = f2val; } return; } /* Calculate three-body energy phi3(Rij, Rik, Rjk) and its derivatives w.r.t Rij, Rik, and Rjk */ static void calc_phi3_dphi3(double const * const params, double const Rij, double const Rik, double const Rjk, double * const phi3, double * const dphi3_dRij, double * const dphi3_dRik, double * const dphi3_dRjk) { /* Unpack parameters */ double f3val; double df3_dRij; double df3_dRik; double df3_dRjk; if (dphi3_dRij != NULL) { f3_df3(params, Rij, Rik, Rjk, &f3val, &df3_dRij, &df3_dRik, &df3_dRjk); *phi3 = f3val; *dphi3_dRij = df3_dRij; *dphi3_dRik = df3_dRik; *dphi3_dRjk = df3_dRjk; } else { f3_df3(params, Rij, Rik, Rjk, &f3val, NULL, NULL, NULL); *phi3 = f3val; } return; }