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MeasurePBC.C

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00001 /***************************************************************************
00002 *cr
00003 *cr (C) Copyright 1995-2019 The Board of Trustees of the
00004 *cr University of Illinois
00005 *cr All Rights Reserved
00006 *cr
00007 ***************************************************************************/
00008 
00009 /***************************************************************************
00010 * RCS INFORMATION:
00011 *
00012 * $RCSfile: MeasurePBC.C,v $
00013 * $Author: johns $ $Locker: $ $State: Exp $
00014 * $Revision: 1.18 $ $Date: 2019年01月17日 21:21:00 $
00015 *
00016 ***************************************************************************
00017 * DESCRIPTION:
00018 * Code to measure atom distances, angles, dihedrals, etc, 
00019 * accounting for periodic boundary conditions
00020 ***************************************************************************/
00021 
00022 #include <stdio.h>
00023 #include <stdlib.h>
00024 #include <math.h>
00025 #include "Measure.h"
00026 #include "AtomSel.h"
00027 #include "Matrix4.h"
00028 #include "utilities.h"
00029 #include "SpatialSearch.h" // for find_within()
00030 #include "MoleculeList.h"
00031 #include "Inform.h"
00032 #include "Timestep.h"
00033 #include "VMDApp.h"
00034 
00035 //
00036 // Find an orthogonal basis R^3 with ob1=b1 
00037 //
00038 
00039 void orthonormal_basis(const float b[9], float e[9]) {
00040 float ob[3*3];
00041 vec_copy(ob+0, b+0);
00042 vec_copy(e+0, ob+0);
00043 vec_normalize(e+0);
00044 vec_triad(ob+3, b+3, -dot_prod(e+0, b+3), e+0);
00045 vec_copy(e+3, ob+3);
00046 vec_normalize(e+3);
00047 vec_triad(ob+6, b+6, -dot_prod(e+0, b+6), e+0);
00048 vec_triad(ob+6, ob+6, -dot_prod(e+3, b+6), e+3);
00049 vec_copy(e+6, ob+6);
00050 vec_normalize(e+6);
00051 }
00052 
00053 //
00054 // Returns basis vectors in coordinates of an orthonormal 
00055 // basis obase. 
00056 //
00057 
00058 void basis_change(const float *base, const float *obase, float *newcoor, int n) {
00059 int i, j;
00060 for (i=0; i<n; i++) {
00061 for (j=0; j<n; j++) {
00062 newcoor[n*i+j] = dot_prod(&base[n*j], &obase[n*i]);
00063 }
00064 }
00065 }
00066 
00067 // Compute matrix that transforms coordinates from an arbitrary PBC cell 
00068 // into an orthonormal unitcell. Since the cell origin is not stored by VMD
00069 // you have to specify it.
00070 int measure_pbc2onc(MoleculeList *mlist, int molid, int frame, const float origin[3], Matrix4 &transform) {
00071 int orig_ts, max_ts;
00072 
00073 Molecule *mol = mlist->mol_from_id(molid);
00074 if( !mol )
00075 return MEASURE_ERR_NOMOLECULE;
00076 
00077 // get current frame number and make sure there are frames
00078 if((orig_ts = mol->frame()) < 0)
00079 return MEASURE_ERR_NOFRAMES;
00080 
00081 // get the max frame number and determine frame range
00082 max_ts = mol->numframes()-1;
00083 if (frame==-2) frame = orig_ts;
00084 else if (frame>max_ts || frame==-1) frame = max_ts;
00085 
00086 Timestep *ts = mol->get_frame(frame);
00087 
00088 Matrix4 AA, BB, CC;
00089 ts->get_transforms(AA, BB, CC);
00090 
00091 // Construct the cell spanning vectors
00092 float cell[9];
00093 cell[0] = AA.mat[12];
00094 cell[1] = AA.mat[13];
00095 cell[2] = AA.mat[14];
00096 cell[3] = BB.mat[12];
00097 cell[4] = BB.mat[13];
00098 cell[5] = BB.mat[14];
00099 cell[6] = CC.mat[12];
00100 cell[7] = CC.mat[13];
00101 cell[8] = CC.mat[14];
00102 
00103 get_transform_to_orthonormal_cell(cell, origin, transform);
00104 
00105 return MEASURE_NOERR;
00106 }
00107 
00108 // Compute matrix that transforms coordinates from an arbitrary cell 
00109 // into an orthonormal unitcell. Since the origin is not stored by VMD
00110 // you have to specify it.
00111 // This is the lowlevel backend of measure_pbc2onc().
00112 
00113 // Here is a 2D example:
00114 // A and B are the are the displacement vectors which are needed to create 
00115 // the neighboring images. The parallelogram denotes the PBC cell with the origin O at its center.
00116 // The sqare to the right indicates the orthonormal unit cell i.e. the area into which the atoms 
00117 // will be wrapped by transformation T.
00118 //
00119 // + B 
00120 // / ^ B' 
00121 // _________/________ | 
00122 // / / / +---|---+ 
00123 // / / / T | | | 
00124 // / O--------/-------> A ====> | O---|--> A' 
00125 // / / | | 
00126 // /_________________/ +-------+ 
00127 
00128 // A = displacement vector along X-axis with length a
00129 // B = displacement vector in XY-plane with length b
00130 // A' = displacement vector along X-axis with length 1
00131 // B' = displacement vector along Y-axis with length 1
00132 // O = origin of the unit cell 
00133 
00134 void get_transform_to_orthonormal_cell(const float *cell, const float *center, Matrix4 &transform) {
00135 // Orthogonalize system:
00136 // Find an orthonormal basis of the cell (in cartesian coords).
00137 // If the cell vectors from VMD/NAMD are used this should actually always
00138 // return the identity matrix due to the way the cell vectors A, B and C
00139 // are defined (i.e. A || x; B lies in the x,y-plane; A, B, C form a right
00140 // hand system).
00141 float obase[3*3];
00142 orthonormal_basis(cell, obase);
00143 
00144 // Get orthonormal base in cartesian coordinates (it is the inverse of the
00145 // obase->cartesian transformation):
00146 float identity[3*3] = {1, 0, 0, 0, 1, 0, 0, 0, 1};
00147 float obase_cartcoor[3*3];
00148 basis_change(obase, identity, obase_cartcoor, 3);
00149 
00150 
00151 // Transform 3x3 into 4x4 matrix:
00152 Matrix4 obase2cartinv;
00153 trans_from_rotate(obase_cartcoor, &obase2cartinv);
00154 
00155 // This is the matrix for the obase->cartesian transformation:
00156 Matrix4 obase2cart = obase2cartinv;
00157 obase2cart.inverse();
00158 
00159 // Get coordinates of cell in terms of obase
00160 float m[3*3]; 
00161 basis_change(cell, obase, m, 3);
00162 Matrix4 rotmat;
00163 trans_from_rotate(m, &rotmat);
00164 rotmat.inverse();
00165 
00166 
00167 // Actually we have:
00168 // transform = translation * obase2cart * obase2cartinv * rotmat * obase2cart
00169 // `------------v------------'
00170 // = 1
00171 transform = obase2cart;
00172 transform.multmatrix(rotmat); // pre-multiplication
00173 
00174 // Finally we need to apply the translation of the origin
00175 float origin[3];
00176 vec_copy(origin, center);
00177 vec_scaled_add(origin, -0.5, &cell[0]);
00178 vec_scaled_add(origin, -0.5, &cell[3]);
00179 vec_scaled_add(origin, -0.5, &cell[6]);
00180 vec_negate(origin, origin);
00181 //printf("origin={%g %g %g}\n", origin[0], origin[1], origin[2]);
00182 transform.translate(origin);
00183 }
00184 
00185 
00186 // Get the array of coordinates of pbc image atoms for the specified selection.
00187 // The cutoff vector defines the region surrounding the pbc cell for which image 
00188 // atoms shall be constructed ({6 8 0} means 6 Angstrom for the direction of A,
00189 // 8 for B and no images in the C direction). The indexmap_array relates each
00190 // image atom to its corresponding main atom.
00191 // In case the molecule was aligned you can supply the alignment matrix which
00192 // is then used to correct for the rotation and shift of the pbc cell.
00193 // Since the pbc cell center is not stored in Timestep it must be provided.
00194 
00195 // The algorithm transforms the unitcell so that the unitcell minus the cutoff fits
00196 // into an orthonormal cell. Now the atoms in the rim can be easily identified and
00197 // wrapped into the neigboring cells. This works only if the largest cutoff
00198 // dimension is smaller than half of the smallest cell dimension. Otherwise a
00199 // slower algorithm is used that wraps each atom into all 26 neighboring cells
00200 // and checks if the image lies within cutoff.
00201 //
00202 // ________________ 
00203 // / ____________ / +---------+
00204 // / / / / | +-----+ |
00205 // / / core / / ----> | | |_|___orthonormal_cell
00206 // / /___________/ / <---- | | | |
00207 // /_______________/ | +-----+ |___rim
00208 // +---------+
00209 //
00210 // Alternatively one can specify a rectangular bounding box into which atoms
00211 // shall be wrapped. It is specified in form of minmax coordinates through
00212 // parameter *box. I.e. coordinates are produced for pbc image atom that lie
00213 // inside the box but outside the central unit cell. This feature can be used
00214 // for instance to retrieve coordinates of the minmax box of a selection when
00215 // the box boundaries exceed the unit cell.
00216 //
00217 // If a selection is provided (sel!=NULL) we return only coordinates that are
00218 // within the cutoff distance of that selection:
00219 
00220 // The results are provided in form of an array of 'extended' coordinates,
00221 // i.e. the coordinates of the requested region that don't lie in the central
00222 // unit cell. In order to identify these coordinates with the respective atoms
00223 // in the central cell an index map is also provided.
00224 
00225 // TODO:
00226 // * Allow requesting specific neighbor cells.
00227 
00228 int measure_pbc_neighbors(MoleculeList *mlist, AtomSel *sel, int molid,
00229 int frame, const Matrix4 *alignment,
00230 const float *center, const float *cutoff, const float *box,
00231 ResizeArray<float> *extcoord_array,
00232 ResizeArray<int> *indexmap_array) {
00233 int orig_ts, max_ts;
00234 if (!box && !cutoff[0] && !cutoff[1] && !cutoff[2]) return MEASURE_NOERR;
00235 
00236 Molecule *mol = mlist->mol_from_id(molid);
00237 if( !mol )
00238 return MEASURE_ERR_NOMOLECULE;
00239 
00240 // get current frame number and make sure there are frames
00241 if((orig_ts = mol->frame()) < 0)
00242 return MEASURE_ERR_NOFRAMES;
00243 
00244 // get the max frame number and determine current frame
00245 max_ts = mol->numframes()-1;
00246 if (frame==-2) frame = orig_ts;
00247 else if (frame>max_ts || frame==-1) frame = max_ts;
00248 
00249 Timestep *ts = mol->get_frame(frame);
00250 if (!ts) return MEASURE_ERR_NOMOLECULE;
00251 
00252 // Get the displacement vectors (in form of translation matrices)
00253 Matrix4 Tpbc[3][2];
00254 ts->get_transforms(Tpbc[0][1], Tpbc[1][1], Tpbc[2][1]);
00255 
00256 // Assign the negative cell translation vectors
00257 Tpbc[0][0] = Tpbc[0][1];
00258 Tpbc[1][0] = Tpbc[1][1];
00259 Tpbc[2][0] = Tpbc[2][1];
00260 Tpbc[0][0].inverse();
00261 Tpbc[1][0].inverse();
00262 Tpbc[2][0].inverse();
00263 
00264 // Construct the cell spanning vectors
00265 float cell[9];
00266 cell[0] = Tpbc[0][1].mat[12];
00267 cell[1] = Tpbc[0][1].mat[13];
00268 cell[2] = Tpbc[0][1].mat[14];
00269 cell[3] = Tpbc[1][1].mat[12];
00270 cell[4] = Tpbc[1][1].mat[13];
00271 cell[5] = Tpbc[1][1].mat[14];
00272 cell[6] = Tpbc[2][1].mat[12];
00273 cell[7] = Tpbc[2][1].mat[13];
00274 cell[8] = Tpbc[2][1].mat[14];
00275 
00276 float len[3];
00277 len[0] = sqrtf(dot_prod(&cell[0], &cell[0]));
00278 len[1] = sqrtf(dot_prod(&cell[3], &cell[3]));
00279 len[2] = sqrtf(dot_prod(&cell[6], &cell[6]));
00280 //printf("len={%.3f %.3f %.3f}\n", len[0], len[1], len[2]);
00281 
00282 int i;
00283 float minlen = len[0];
00284 if (len[1] && len[1]<minlen) minlen = len[1];
00285 if (len[2] && len[2]<minlen) minlen = len[2];
00286 minlen--;
00287 
00288 // The algorithm works only for atoms in adjacent neighbor cells.
00289 if (!box && (cutoff[0]>=len[0] || cutoff[1]>=len[1] || cutoff[2]>=len[2])) {
00290 return MEASURE_ERR_BADCUTOFF;
00291 }
00292 
00293 bool bigrim = 1;
00294 float corecell[9];
00295 float diag[3];
00296 float origin[3];
00297 memset(origin, 0, 3L*sizeof(float));
00298 Matrix4 M_norm;
00299 
00300 if (box) {
00301 // Get the matrix M_norm that transforms all atoms inside the 
00302 // unit cell into the normalized unitcell spanned by 
00303 // {1/len[0] 0 0} {0 1/len[1] 0} {0 0 1/len[2]}.
00304 bigrim = 1;
00305 
00306 float vtmp[3];
00307 vec_add(vtmp, &cell[0], &cell[3]);
00308 vec_add(diag, &cell[6], vtmp);
00309 //printf("diag={%.3f %.3f %.3f}\n", diag[0], diag[1], diag[2]);
00310 
00311 // Finally we need to apply the translation of the cell origin
00312 vec_copy(origin, center);
00313 vec_scaled_add(origin, -0.5, &cell[0]);
00314 vec_scaled_add(origin, -0.5, &cell[3]);
00315 vec_scaled_add(origin, -0.5, &cell[6]);
00316 vec_negate(origin, origin);
00317 //printf("origin={%.3f %.3f %.3f}\n", origin[0], origin[1], origin[2]);
00318 
00319 } else if (2.0f*cutoff[0]<minlen && 2.0f*cutoff[1]<minlen && 2.0f*cutoff[2]<minlen) {
00320 // The cutoff must not be larger than half of the smallest cell dimension
00321 // otherwise we would have to use a less efficient algorithm.
00322 
00323 // Get the matrix M_norm that transforms all atoms inside the 
00324 // corecell into the orthonormal unitcell spanned by {1 0 0} {0 1 0} {0 0 1}.
00325 // The corecell ist the pbc cell minus cutoffs for each dimension.
00326 vec_scale(&corecell[0], (len[0]-cutoff[0])/len[0], &cell[0]);
00327 vec_scale(&corecell[3], (len[1]-cutoff[1])/len[1], &cell[3]);
00328 vec_scale(&corecell[6], (len[2]-cutoff[2])/len[2], &cell[6]);
00329 get_transform_to_orthonormal_cell(corecell, center, M_norm);
00330 //printf("Using algorithm for small PBC environment.\n");
00331 
00332 } else {
00333 // Get the matrix M_norm that transforms all atoms inside the 
00334 // unit cell into the orthonormal unitcell spanned by {1 0 0} {0 1 0} {0 0 1}.
00335 get_transform_to_orthonormal_cell(cell, center, M_norm);
00336 
00337 bigrim = 1;
00338 //printf("Using algorithm for large PBC environment.\n");
00339 }
00340 
00341 // In case the molecule was aligned our pbc cell is rotated and shifted.
00342 // In order to transform a point P into the orthonormal cell (P') it 
00343 // first has to be unaligned (the inverse of the alignment):
00344 // P' = M_norm * (alignment^-1) * P
00345 Matrix4 alignmentinv(*alignment);
00346 alignmentinv.inverse();
00347 Matrix4 M_coretransform(M_norm);
00348 M_coretransform.multmatrix(alignmentinv);
00349 
00350 //printf("alignment = \n");
00351 //print_Matrix4(alignment);
00352 
00353 // Similarly if we want to transform a point P into its image P' we
00354 // first have to unalign it, then apply the PBC translation and 
00355 // finally realign:
00356 // P' = alignment * Tpbc * (alignment^-1) * P
00357 // `-------------v--------------'
00358 // transform
00359 int j, u;
00360 Matrix4 Tpbc_aligned[3][2];
00361 if (!box) {
00362 for (i=0; i<3; i++) {
00363 for (j=0; j<2; j++) {
00364 Tpbc_aligned[i][j].loadmatrix(*alignment);
00365 Tpbc_aligned[i][j].multmatrix(Tpbc[i][j]);
00366 Tpbc_aligned[i][j].multmatrix(alignmentinv);
00367 }
00368 }
00369 }
00370 
00371 Matrix4 M[3];
00372 float *coords = ts->pos;
00373 float *coor;
00374 float orthcoor[3], wrapcoor[3];
00375 
00376 //printf("cutoff={%.3f %.3f %.3f}\n", cutoff[0], cutoff[1], cutoff[2]);
00377 
00378 if (box) {
00379 float min_coord[3], max_coord[3];
00380 // Increase box by cutoff
00381 vec_sub(min_coord, box, cutoff);
00382 vec_add(max_coord, box+3, cutoff);
00383 //printf("Wrapping atoms into rectangular bounding box.\n");
00384 //printf("min_coord={%.3f %.3f %.3f}\n", min_coord[0], min_coord[1], min_coord[2]);
00385 //printf("max_coord={%.3f %.3f %.3f}\n", max_coord[0], max_coord[1], max_coord[2]);
00386 vec_add(min_coord, min_coord, origin);
00387 vec_add(max_coord, max_coord, origin);
00388 
00389 float testcoor[9];
00390 int idx, k;
00391 // Loop over all atoms
00392 for (idx=0; idx<ts->num; idx++) { 
00393 coor = coords+3L*idx;
00394 
00395 // Apply the inverse alignment transformation
00396 // to the current test point.
00397 M_coretransform.multpoint3d(coor, orthcoor);
00398 
00399 // Loop over all 26 neighbor cells
00400 // x
00401 for (i=-1; i<=1; i++) {
00402 // Choose the direction of translation
00403 if (i>0) M[0].loadmatrix(Tpbc[0][1]);
00404 else if (i<0) M[0].loadmatrix(Tpbc[0][0]);
00405 else M[0].identity();
00406 // Translate the unaligned atom
00407 M[0].multpoint3d(orthcoor, testcoor);
00408 
00409 // y
00410 for (j=-1; j<=1; j++) {
00411 // Choose the direction of translation
00412 if (j>0) M[1].loadmatrix(Tpbc[1][1]);
00413 else if (j<0) M[1].loadmatrix(Tpbc[1][0]);
00414 else M[1].identity();
00415 // Translate the unaligned atom
00416 M[1].multpoint3d(testcoor, testcoor+3);
00417 
00418 // z
00419 for (k=-1; k<=1; k++) {
00420 if(i==0 && j==0 && k==0) continue;
00421 
00422 // Choose the direction of translation
00423 if (k>0) M[2].loadmatrix(Tpbc[2][1]);
00424 else if (k<0) M[2].loadmatrix(Tpbc[2][0]);
00425 else M[2].identity();
00426 // Translate the unaligned atom
00427 M[2].multpoint3d(testcoor+3, testcoor+6);
00428 
00429 // Realign atom
00430 alignment->multpoint3d(testcoor+6, wrapcoor);
00431 
00432 vec_add(testcoor+6, wrapcoor, origin);
00433 if (testcoor[6]<min_coord[0] || testcoor[6]>max_coord[0]) continue;
00434 if (testcoor[7]<min_coord[1] || testcoor[7]>max_coord[1]) continue;
00435 if (testcoor[8]<min_coord[2] || testcoor[8]>max_coord[2]) continue;
00436 
00437 // Atom is inside cutoff, add it to the list 
00438 extcoord_array->append3(&wrapcoor[0]);
00439 indexmap_array->append(idx);
00440 }
00441 }
00442 }
00443 }
00444 
00445 } else if (bigrim) {
00446 // This is the more general but slower algorithm.
00447 // We loop over all atoms, move each atom to all 26 neighbor cells
00448 // and check if it lies inside cutoff
00449 float min_coord[3], max_coord[3];
00450 min_coord[0] = -cutoff[0]/len[0];
00451 min_coord[1] = -cutoff[1]/len[1];
00452 min_coord[2] = -cutoff[2]/len[2];
00453 max_coord[0] = 1.0f + cutoff[0]/len[0];
00454 max_coord[1] = 1.0f + cutoff[1]/len[1];
00455 max_coord[2] = 1.0f + cutoff[2]/len[2];
00456 
00457 float testcoor[3];
00458 int idx, k;
00459 // Loop over all atoms
00460 for (idx=0; idx<ts->num; idx++) { 
00461 coor = coords+3L*idx;
00462 
00463 // Apply the PBC --> orthonormal unitcell transformation
00464 // to the current test point.
00465 M_coretransform.multpoint3d(coor, orthcoor);
00466 
00467 // Loop over all 26 neighbor cells
00468 // x
00469 for (i=-1; i<=1; i++) {
00470 testcoor[0] = orthcoor[0]+(float)(i);
00471 if (testcoor[0]<min_coord[0] || testcoor[0]>max_coord[0]) continue;
00472 
00473 // Choose the direction of translation
00474 if (i>0) M[0].loadmatrix(Tpbc_aligned[0][1]);
00475 else if (i<0) M[0].loadmatrix(Tpbc_aligned[0][0]);
00476 else M[0].identity();
00477 
00478 // y
00479 for (j=-1; j<=1; j++) {
00480 testcoor[1] = orthcoor[1]+(float)(j);
00481 if (testcoor[1]<min_coord[1] || testcoor[1]>max_coord[1]) continue;
00482 
00483 // Choose the direction of translation
00484 if (j>0) M[1].loadmatrix(Tpbc_aligned[1][1]);
00485 else if (j<0) M[1].loadmatrix(Tpbc_aligned[1][0]);
00486 else M[1].identity();
00487 
00488 // z
00489 for (k=-1; k<=1; k++) {
00490 testcoor[2] = orthcoor[2]+(float)(k);
00491 if (testcoor[2]<min_coord[2] || testcoor[2]>max_coord[2]) continue;
00492 
00493 if(i==0 && j==0 && k==0) continue;
00494 
00495 // Choose the direction of translation
00496 if (k>0) M[2].loadmatrix(Tpbc_aligned[2][1]);
00497 else if (k<0) M[2].loadmatrix(Tpbc_aligned[2][0]);
00498 else M[2].identity();
00499 
00500 M[0].multpoint3d(coor, wrapcoor);
00501 M[1].multpoint3d(wrapcoor, wrapcoor);
00502 M[2].multpoint3d(wrapcoor, wrapcoor);
00503 
00504 // Atom is inside cutoff, add it to the list 
00505 extcoord_array->append3(&wrapcoor[0]);
00506 indexmap_array->append(idx);
00507 }
00508 }
00509 }
00510 }
00511 
00512 } else {
00513 Matrix4 Mtmp;
00514 
00515 for (i=0; i < ts->num; i++) { 
00516 // Apply the PBC --> orthonormal unitcell transformation
00517 // to the current test point.
00518 M_coretransform.multpoint3d(coords+3L*i, orthcoor);
00519 
00520 // Determine in which cell we are.
00521 int cellindex[3]; 
00522 if (orthcoor[0]<0) cellindex[0] = -1;
00523 else if (orthcoor[0]>1) cellindex[0] = 1;
00524 else cellindex[0] = 0;
00525 if (orthcoor[1]<0) cellindex[1] = -1;
00526 else if (orthcoor[1]>1) cellindex[1] = 1;
00527 else cellindex[1] = 0;
00528 if (orthcoor[2]<0) cellindex[2] = -1;
00529 else if (orthcoor[2]>1) cellindex[2] = 1;
00530 else cellindex[2] = 0;
00531 
00532 // All zero means we're inside the core --> no image.
00533 if (!cellindex[0] && !cellindex[1] && !cellindex[2]) continue;
00534 
00535 // Choose the direction of translation
00536 if (orthcoor[0]<0) M[0].loadmatrix(Tpbc_aligned[0][1]);
00537 else if (orthcoor[0]>1) M[0].loadmatrix(Tpbc_aligned[0][0]);
00538 if (orthcoor[1]<0) M[1].loadmatrix(Tpbc_aligned[1][1]);
00539 else if (orthcoor[1]>1) M[1].loadmatrix(Tpbc_aligned[1][0]);
00540 if (orthcoor[2]<0) M[2].loadmatrix(Tpbc_aligned[2][1]);
00541 else if (orthcoor[2]>1) M[2].loadmatrix(Tpbc_aligned[2][0]);
00542 
00543 // Create wrapped copies of the atom:
00544 // x, y, z planes
00545 coor = coords+3L*i;
00546 for (u=0; u<3; u++) {
00547 if (cellindex[u] && cutoff[u]) {
00548 M[u].multpoint3d(coor, wrapcoor);
00549 extcoord_array->append3(&wrapcoor[0]);
00550 indexmap_array->append(i);
00551 }
00552 }
00553 
00554 Mtmp = M[0];
00555 
00556 // xy edge
00557 if (cellindex[0] && cellindex[1] && cutoff[0] && cutoff[1]) {
00558 M[0].multmatrix(M[1]);
00559 M[0].multpoint3d(coor, wrapcoor);
00560 extcoord_array->append3(&wrapcoor[0]);
00561 indexmap_array->append(i);
00562 }
00563 
00564 // yz edge
00565 if (cellindex[1] && cellindex[2] && cutoff[1] && cutoff[2]) {
00566 M[1].multmatrix(M[2]);
00567 M[1].multpoint3d(coor, wrapcoor);
00568 extcoord_array->append3(&wrapcoor[0]);
00569 indexmap_array->append(i);
00570 }
00571 
00572 // zx edge
00573 if (cellindex[0] && cellindex[2] && cutoff[0] && cutoff[2]) {
00574 M[2].multmatrix(Mtmp);
00575 M[2].multpoint3d(coor, wrapcoor);
00576 extcoord_array->append3(&wrapcoor[0]);
00577 indexmap_array->append(i);
00578 }
00579 
00580 // xyz corner
00581 if (cellindex[0] && cellindex[1] && cellindex[2]) {
00582 M[1].multmatrix(Mtmp);
00583 M[1].multpoint3d(coor, wrapcoor);
00584 extcoord_array->append3(&wrapcoor[0]);
00585 indexmap_array->append(i);
00586 }
00587 
00588 }
00589 
00590 } // endif
00591 
00592 // If a selection was provided we select extcoords
00593 // within cutoff of the original selection:
00594 if (sel) {
00595 int numext = sel->selected+indexmap_array->num();
00596 float *extcoords = new float[3L*numext];
00597 int *indexmap = new int[numext];
00598 int *others = new int[numext];
00599 memset(others, 0, numext);
00600 
00601 // Use the largest given cutoff
00602 float maxcutoff = cutoff[0];
00603 for (i=1; i<3; i++) {
00604 if (cutoff[i]>maxcutoff) maxcutoff = cutoff[i];
00605 }
00606 
00607 // Prepare C-array of coordinates for find_within()
00608 j=0;
00609 for (i=0; i < sel->num_atoms; i++) { 
00610 if (!sel->on[i]) continue; //atom is not selected
00611 extcoords[3L*j] = coords[3L*i];
00612 extcoords[3L*j+1] = coords[3L*i+1];
00613 extcoords[3L*j+2] = coords[3L*i+2];
00614 indexmap[j] = i;
00615 others[j++] = 1;
00616 }
00617 for (i=0; i<indexmap_array->num(); i++) {
00618 extcoords[3L*j] = (*extcoord_array)[3L*i];
00619 extcoords[3L*j+1] = (*extcoord_array)[3L*i+1];
00620 extcoords[3L*j+2] = (*extcoord_array)[3L*i+2];
00621 indexmap[j] = (*indexmap_array)[i];
00622 others[j++] = 0;
00623 }
00624 
00625 // Initialize flags array to true, find_within() results are AND'd/OR'd in.
00626 int *flgs = new int[numext];
00627 for (i=0; i<numext; i++) {
00628 flgs[i] = 1;
00629 }
00630 
00631 // Find coordinates from extcoords that are within cutoff of the ones
00632 // with flagged in 'others' and set the flgs accordingly:
00633 find_within(extcoords, flgs, others, numext, maxcutoff);
00634 
00635 extcoord_array->clear();
00636 indexmap_array->clear();
00637 for (i=sel->selected; i<numext; i++) {
00638 if (!flgs[i]) continue;
00639 
00640 extcoord_array->append3(&extcoords[3L*i]);
00641 indexmap_array->append(indexmap[i]);
00642 }
00643 
00644 }
00645 
00646 return MEASURE_NOERR;
00647 } 
00648 
00649 // Computes the rectangular bounding box for the PBC cell.
00650 // If the molecule was rotated/moved you can supply the transformation
00651 // matrix and you'll get the bounding box of the transformed cell.
00652 int compute_pbcminmax(MoleculeList *mlist, int molid, int frame, 
00653 const float *center, const Matrix4 *transform,
00654 float *min, float *max) {
00655 Molecule *mol = mlist->mol_from_id(molid);
00656 if( !mol )
00657 return MEASURE_ERR_NOMOLECULE;
00658 
00659 Timestep *ts = mol->get_frame(frame);
00660 if (!ts) return MEASURE_ERR_NOFRAMES;
00661 
00662 // Get the displacement vectors (in form of translation matrices)
00663 Matrix4 Tpbc[3];
00664 ts->get_transforms(Tpbc[0], Tpbc[1], Tpbc[2]);
00665 
00666 // Construct the cell spanning vectors
00667 float cell[9];
00668 cell[0] = Tpbc[0].mat[12];
00669 cell[1] = Tpbc[0].mat[13];
00670 cell[2] = Tpbc[0].mat[14];
00671 cell[3] = Tpbc[1].mat[12];
00672 cell[4] = Tpbc[1].mat[13];
00673 cell[5] = Tpbc[1].mat[14];
00674 cell[6] = Tpbc[2].mat[12];
00675 cell[7] = Tpbc[2].mat[13];
00676 cell[8] = Tpbc[2].mat[14];
00677 
00678 #if 0
00679 float len[3];
00680 len[0] = sqrtf(dot_prod(&cell[0], &cell[0]));
00681 len[1] = sqrtf(dot_prod(&cell[3], &cell[3]));
00682 len[2] = sqrtf(dot_prod(&cell[6], &cell[6]));
00683 #endif
00684 
00685 // Construct all 8 corners (nodes) of the bounding box
00686 float node[8*3];
00687 int n=0;
00688 float i, j, k;
00689 for (i=-0.5; i<1.f; i+=1.f) {
00690 for (j=-0.5; j<1.f; j+=1.f) {
00691 for (k=-0.5; k<1.f; k+=1.f) {
00692 // Apply the translation of the origin
00693 vec_copy(node+3L*n, center);
00694 vec_scaled_add(node+3L*n, i, &cell[0]);
00695 vec_scaled_add(node+3L*n, j, &cell[3]);
00696 vec_scaled_add(node+3L*n, k, &cell[6]);
00697 
00698 // Apply global alignment transformation
00699 transform->multpoint3d(node+3L*n, node+3L*n);
00700 n++;
00701 }
00702 }
00703 }
00704 
00705 // Find minmax coordinates of all corners
00706 for (n=0; n<8; n++) {
00707 if (!n || node[3L*n ]<min[0]) min[0] = node[3L*n];
00708 if (!n || node[3L*n+1]<min[1]) min[1] = node[3L*n+1];
00709 if (!n || node[3L*n+2]<min[2]) min[2] = node[3L*n+2];
00710 if (!n || node[3L*n ]>max[0]) max[0] = node[3L*n];
00711 if (!n || node[3L*n+1]>max[1]) max[1] = node[3L*n+1];
00712 if (!n || node[3L*n+2]>max[2]) max[2] = node[3L*n+2];
00713 }
00714 
00715 return MEASURE_NOERR;
00716 }

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