1 // ****************************************************************************** 2 // 3 // Title: Force Field X. 4 // Description: Force Field X - Software for Molecular Biophysics. 5 // Copyright: Copyright (c) Michael J. Schnieders 2001-2025. 6 // 7 // This file is part of Force Field X. 8 // 9 // Force Field X is free software; you can redistribute it and/or modify it 10 // under the terms of the GNU General Public License version 3 as published by 11 // the Free Software Foundation. 12 // 13 // Force Field X is distributed in the hope that it will be useful, but WITHOUT 14 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 15 // FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 16 // details. 17 // 18 // You should have received a copy of the GNU General Public License along with 19 // Force Field X; if not, write to the Free Software Foundation, Inc., 59 Temple 20 // Place, Suite 330, Boston, MA 02111-1307 USA 21 // 22 // Linking this library statically or dynamically with other modules is making a 23 // combined work based on this library. Thus, the terms and conditions of the 24 // GNU General Public License cover the whole combination. 25 // 26 // As a special exception, the copyright holders of this library give you 27 // permission to link this library with independent modules to produce an 28 // executable, regardless of the license terms of these independent modules, and 29 // to copy and distribute the resulting executable under terms of your choice, 30 // provided that you also meet, for each linked independent module, the terms 31 // and conditions of the license of that module. An independent module is a 32 // module which is not derived from or based on this library. If you modify this 33 // library, you may extend this exception to your version of the library, but 34 // you are not obligated to do so. If you do not wish to do so, delete this 35 // exception statement from your version. 36 // 37 // ****************************************************************************** 38 package ffx.numerics.multipole; 39 40 import jdk.incubator.vector.DoubleVector; 41 42 import static ffx.numerics.multipole.TholeTensorGlobalSIMD.tholeSource; 43 44 /** 45 * The TholeTensorQI class computes derivatives of Thole damping via recursion to order <= 4 for 46 * Cartesian multipoles in a quasi-internal frame. 47 * 48 * @author Michael J. Schnieders 49 * @see <a href="http://doi.org/10.1142/9789812830364_0002" target="_blank"> Matt Challacombe, Eric 50 * Schwegler and Jan Almlof, Modern developments in Hartree-Fock theory: Fast methods for 51 * computing the Coulomb matrix. Computational Chemistry: Review of Current Trends. pp. 53-107, 52 * Ed. J. Leczszynski, World Scientifc, 1996. </a> 53 * @since 1.0 54 */ 55 public class TholeTensorQISIMD extends CoulombTensorQISIMD { 56 57 /** 58 * Thole damping parameter is set to min(pti,ptk)). 59 */ 60 private DoubleVector thole; 61 62 /** 63 * AiAk parameter = 1/(alphaI^6*alphaK^6) where alpha is polarizability. 64 */ 65 private DoubleVector AiAk; 66 67 /** 68 * Constructor for TholeTensorQI. 69 * 70 * @param order Tensor order. 71 * @param thole Thole damping parameter is set to min(pti,ptk)). 72 * @param AiAk parameter = 1/(alphaI^6*alphaK^6) where alpha is polarizability. 73 */ 74 public TholeTensorQISIMD(int order, DoubleVector thole, DoubleVector AiAk) { 75 super(order); 76 this.thole = thole; 77 this.AiAk = AiAk; 78 this.operator = Operator.THOLE_FIELD; 79 80 // Source terms are currently defined up to order 4. 81 assert (order <= 4); 82 } 83 84 /** 85 * Set Thole damping parameters 86 * 87 * @param thole a double. 88 * @param AiAk a double. 89 */ 90 public void setThole(DoubleVector thole, DoubleVector AiAk) { 91 this.thole = thole; 92 this.AiAk = AiAk; 93 } 94 95 /** 96 * Check if the Thole damping is exponential is greater than zero (or the interaction can be 97 * neglected). 98 * 99 * @param r The separation distance. 100 * @return True if -thole*u^3 is greater than -50.0. 101 */ 102 public boolean checkThole(DoubleVector r) { 103 return TholeTensorGlobalSIMD.checkThole(thole, AiAk, r); 104 } 105 106 /** 107 * Generate source terms for the Challacombe et al. recursion. 108 * 109 * @param T000 Location to store the source terms. 110 */ 111 protected void source(DoubleVector[] T000) { 112 // Compute the normal Coulomb auxiliary term. 113 super.source(T000); 114 115 // Add the Thole damping terms: edamp = exp(-thole*u^3). 116 tholeSource(thole, AiAk, R, T000); 117 } 118 119 }