src/gromacs/gmxlib/calch.c

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  37 #ifdef HAVE_CONFIG_H
  38 #include <config.h>
  39 #endif
  40
  41 #include "macros.h"
  42 #include "calch.h"
  43 #include "gromacs/math/utilities.h"
  44 #include "vec.h"
  45 #include "physics.h"
  46
  47 #include "gmx_fatal.h"
  48
  49 #define xAI xa[0]
  50 #define xAJ xa[1]
  51 #define xAK xa[2]
  52 #define xAL xa[3]
  53 #define xH1 xh[0]
  54 #define xH2 xh[1]
  55 #define xH3 xh[2]
  56 #define xH4 xh[3]
  57
  58 /* The source code in this file should be thread-safe.
  59       Please keep it that way. */
  60
  61 static void gen_waterhydrogen(int nh, rvec xa[], rvec xh[], int *l)
  62 {
  63 #define AA 0.081649
  64 #define BB 0.0
  65 #define CC 0.0577350
  66     const  rvec   matrix1[6] = {
  67         { AA,     BB,     CC },
  68         { AA,     BB,     CC },
  69         { AA,     BB,     CC },
  70         { -AA,    BB,     CC },
  71         { -AA,    BB,     CC },
  72         { BB,     AA,    -CC }
  73     };
  74     const  rvec   matrix2[6] = {
  75         { -AA,   BB,   CC },
  76         { BB,    AA,  -CC },
  77         { BB,   -AA,  -CC },
  78         { BB,    AA,  -CC },
  79         { BB,   -AA,  -CC },
  80         { BB,   -AA,  -CC }
  81     };
  82 #undef AA
  83 #undef BB
  84 #undef CC
  85     int        m;
  86     rvec       kkk;
  87
  88     /* This was copied from Gromos */
  89     for (m = 0; (m < DIM); m++)
  90     {
  91         xH1[m] = xAI[m]+matrix1[*l][m];
  92         xH2[m] = xAI[m]+matrix2[*l][m];
  93     }
  94     if (nh > 2)
  95     {
  96         copy_rvec(xAI, xH3);
  97     }
  98     if (nh > 3)
  99     {
 100         copy_rvec(xAI, xH4);
 101     }
 102
 103     *l = (*l+1) % 6;
 104 }
 105
 106 void calc_h_pos(int nht, rvec xa[], rvec xh[], int *l)
 107 {
 108 #define alfaH   (acos(-1/3.0)) /* 109.47 degrees */
 109 #define alfaHpl (2*M_PI/3)     /* 120 degrees */
 110 #define distH   0.1
 111
 112 #define alfaCOM (DEG2RAD*117)
 113 #define alfaCO  (DEG2RAD*121)
 114 #define alfaCOA (DEG2RAD*115)
 115
 116 #define distO   0.123
 117 #define distOA  0.125
 118 #define distOM  0.136
 119
 120     rvec sa, sb, sij;
 121     real s6, rij, ra, rb, xd;
 122     int  d;
 123
 124     s6 = 0.5*sqrt(3.e0);
 125
 126     /* common work for constructing one, two or three dihedral hydrogens */
 127     switch (nht)
 128     {
 129         case 2:
 130         case 3:
 131         case 4:
 132         case 8:
 133         case 9:
 134             rij = 0.e0;
 135             for (d = 0; (d < DIM); d++)
 136             {
 137                 xd     = xAJ[d];
 138                 sij[d] = xAI[d]-xd;
 139                 sb[d]  = xd-xAK[d];
 140                 rij   += sqr(sij[d]);
 141             }
 142             rij    = sqrt(rij);
 143             sa[XX] = sij[YY]*sb[ZZ]-sij[ZZ]*sb[YY];
 144             sa[YY] = sij[ZZ]*sb[XX]-sij[XX]*sb[ZZ];
 145             sa[ZZ] = sij[XX]*sb[YY]-sij[YY]*sb[XX];
 146             ra     = 0.e0;
 147             for (d = 0; (d < DIM); d++)
 148             {
 149                 sij[d] = sij[d]/rij;
 150                 ra    += sqr(sa[d]);
 151             }
 152             ra = sqrt(ra);
 153             for (d = 0; (d < DIM); d++)
 154             {
 155                 sa[d] = sa[d]/ra;
 156             }
 157
 158             sb[XX] = sa[YY]*sij[ZZ]-sa[ZZ]*sij[YY];
 159             sb[YY] = sa[ZZ]*sij[XX]-sa[XX]*sij[ZZ];
 160             sb[ZZ] = sa[XX]*sij[YY]-sa[YY]*sij[XX];
 161             break;
 162     } /* end switch */
 163
 164     switch (nht)
 165     {
 166         case 1: /* construct one planar hydrogen (peptide,rings) */
 167             rij = 0.e0;
 168             rb  = 0.e0;
 169             for (d = 0; (d < DIM); d++)
 170             {
 171                 sij[d] = xAI[d]-xAJ[d];
 172                 sb[d]  = xAI[d]-xAK[d];
 173                 rij   += sqr(sij[d]);
 174                 rb    += sqr(sb[d]);
 175             }
 176             rij = sqrt(rij);
 177             rb  = sqrt(rb);
 178             ra  = 0.e0;
 179             for (d = 0; (d < DIM); d++)
 180             {
 181                 sa[d] = sij[d]/rij+sb[d]/rb;
 182                 ra   += sqr(sa[d]);
 183             }
 184             ra = sqrt(ra);
 185             for (d = 0; (d < DIM); d++)
 186             {
 187                 xH1[d] = xAI[d]+distH*sa[d]/ra;
 188             }
 189             break;
 190         case 2: /* one single hydrogen, e.g. hydroxyl */
 191             for (d = 0; (d < DIM); d++)
 192             {
 193                 xH1[d] = xAI[d]+distH*sin(alfaH)*sb[d]-distH*cos(alfaH)*sij[d];
 194             }
 195             break;
 196         case 3: /* two planar hydrogens, e.g. -NH2 */
 197             for (d = 0; (d < DIM); d++)
 198             {
 199                 xH1[d] = xAI[d]-distH*sin(alfaHpl)*sb[d]-distH*cos(alfaHpl)*sij[d];
 200                 xH2[d] = xAI[d]+distH*sin(alfaHpl)*sb[d]-distH*cos(alfaHpl)*sij[d];
 201             }
 202             break;
 203         case 4: /* two or three tetrahedral hydrogens, e.g. -CH3 */
 204             for (d = 0; (d < DIM); d++)
 205             {
 206                 xH1[d] = xAI[d]+distH*sin(alfaH)*sb[d]-distH*cos(alfaH)*sij[d];
 207                 xH2[d] = ( xAI[d]
 208                            - distH*sin(alfaH)*0.5*sb[d]
 209                            + distH*sin(alfaH)*s6*sa[d]
 210                            - distH*cos(alfaH)*sij[d] );
 211                 if (xH3[XX] != NOTSET && xH3[YY] != NOTSET && xH3[ZZ] != NOTSET)
 212                 {
 213                     xH3[d] = ( xAI[d]
 214                                - distH*sin(alfaH)*0.5*sb[d]
 215                                - distH*sin(alfaH)*s6*sa[d]
 216                                - distH*cos(alfaH)*sij[d] );
 217                 }
 218             }
 219             break;
 220         case 5: /* one tetrahedral hydrogen, e.g. C3CH */
 221         {
 222             real center;
 223             rvec dxc;
 224
 225             for (d = 0; (d < DIM); d++)
 226             {
 227                 center = (xAJ[d]+xAK[d]+xAL[d])/3.0;
 228                 dxc[d] = xAI[d]-center;
 229             }
 230             center = norm(dxc);
 231             for (d = 0; (d < DIM); d++)
 232             {
 233                 xH1[d] = xAI[d]+dxc[d]*distH/center;
 234             }
 235             break;
 236         }
 237         case 6: /* two tetrahedral hydrogens, e.g. C-CH2-C */
 238         {
 239             rvec rBB, rCC1, rCC2, rNN;
 240             real bb, nn;
 241
 242             for (d = 0; (d < DIM); d++)
 243             {
 244                 rBB[d] = xAI[d]-0.5*(xAJ[d]+xAK[d]);
 245             }
 246             bb = norm(rBB);
 247
 248             rvec_sub(xAI, xAJ, rCC1);
 249             rvec_sub(xAI, xAK, rCC2);
 250             cprod(rCC1, rCC2, rNN);
 251             nn = norm(rNN);
 252
 253             for (d = 0; (d < DIM); d++)
 254             {
 255                 xH1[d] = xAI[d]+distH*(cos(alfaH/2.0)*rBB[d]/bb+
 256                                        sin(alfaH/2.0)*rNN[d]/nn);
 257                 xH2[d] = xAI[d]+distH*(cos(alfaH/2.0)*rBB[d]/bb-
 258                                        sin(alfaH/2.0)*rNN[d]/nn);
 259             }
 260             break;
 261         }
 262         case 7: /* two water hydrogens */
 263             gen_waterhydrogen(2, xa, xh, l);
 264             break;
 265         case 10: /* three water hydrogens */
 266             gen_waterhydrogen(3, xa, xh, l);
 267             break;
 268         case 11: /* four water hydrogens */
 269             gen_waterhydrogen(4, xa, xh, l);
 270             break;
 271         case 8: /* two carboxyl oxygens, -COO- */
 272             for (d = 0; (d < DIM); d++)
 273             {
 274                 xH1[d] = xAI[d]-distOM*sin(alfaCOM)*sb[d]-distOM*cos(alfaCOM)*sij[d];
 275                 xH2[d] = xAI[d]+distOM*sin(alfaCOM)*sb[d]-distOM*cos(alfaCOM)*sij[d];
 276             }
 277             break;
 278         case 9:          /* carboxyl oxygens and hydrogen, -COOH */
 279         {
 280             rvec xa2[4]; /* i,j,k,l   */
 281
 282             /* first add two oxygens */
 283             for (d = 0; (d < DIM); d++)
 284             {
 285                 xH1[d] = xAI[d]-distO *sin(alfaCO )*sb[d]-distO *cos(alfaCO )*sij[d];
 286                 xH2[d] = xAI[d]+distOA*sin(alfaCOA)*sb[d]-distOA*cos(alfaCOA)*sij[d];
 287             }
 288
 289             /* now use rule 2 to add hydrogen to 2nd oxygen */
 290             copy_rvec(xH2, xa2[0]); /* new i = n' */
 291             copy_rvec(xAI, xa2[1]); /* new j = i  */
 292             copy_rvec(xAJ, xa2[2]); /* new k = j  */
 293             copy_rvec(xAK, xa2[3]); /* new l = k, not used */
 294             calc_h_pos(2, xa2, (xh+2), l);
 295
 296             break;
 297         }
 298         default:
 299             gmx_fatal(FARGS, "Invalid argument (%d) for nht in routine genh\n", nht);
 300     } /* end switch */
 301 }