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37 #ifndef GMX_PBCUTIL_PBC_H
38 #define GMX_PBCUTIL_PBC_H
42 #include "gromacs/math/vectypes.h"
43 #include "gromacs/utility/arrayref.h"
44 #include "gromacs/utility/basedefinitions.h"
45 #include "gromacs/utility/real.h"
59 //! Strings corresponding to epbc enum values.
60 extern const char* epbc_names[epbcNR + 1];
62 /* Maximum number of combinations of single triclinic box vectors
63 * required to shift atoms that are within a brick of the size of
64 * the diagonal of the box to within the maximum cut-off distance.
66 #define MAX_NTRICVEC 12
68 /*! \brief Structure containing info on periodic boundary conditions */
73 //! Number of dimensions in which PBC is exerted
75 /*! \brief Determines how to compute distance vectors.
77 * Indicator of how to compute distance vectors, depending
78 * on PBC type (depends on ePBC and dimensions with(out) DD)
82 /*! \brief Used for selecting which dimensions to use in PBC.
84 * In case of 1-D PBC this indicates which dimension is used,
85 * in case of 2-D PBC this indicates the opposite
88 //! The simulation box
90 //! The lengths of the diagonal of the full box
92 //! Halve of the above
94 //! Negative of the above
96 //! Maximum allowed cutoff squared for the box and PBC used
98 /*! \brief Number of triclinic shift vectors.
100 * Number of triclinic shift vectors depends on the skewedness
101 * of the box, that is mostly on the angles. For triclinic boxes
102 * we first take the closest image along each Cartesian dimension
103 * independently. When the resulting distance^2 is larger than
104 * max_cutoff2, up to ntric_vec triclinic shift vectors need to
105 * be tried. Because of the restrictions imposed on the unit-cell
106 * by GROMACS, ntric_vec <= MAX_NTRICVEC = 12.
109 //! The triclinic shift vectors in grid cells. Internal use only.
110 ivec tric_shift[MAX_NTRICVEC];
111 //! The triclinic shift vectors in length units
112 rvec tric_vec[MAX_NTRICVEC];
115 #define TRICLINIC(box) ((box)[YY][XX] != 0 || (box)[ZZ][XX] != 0 || (box)[ZZ][YY] != 0)
123 ecenterTRIC, /* 0.5*(a+b+c) */
124 ecenterRECT, /* (0.5*a[x],0.5*b[y],0.5*c[z]) */
125 ecenterZERO, /* (0,0,0) */
126 ecenterDEF = ecenterTRIC
131 /*! \brief Returns the number of dimensions that use pbc
133 * \param[in] ePBC The periodic boundary condition type
134 * \return the number of dimensions that use pbc, starting at X
136 int ePBC2npbcdim(int ePBC);
138 /*! \brief Dump the contents of the pbc structure to the file
140 * \param[in] fp The file pointer to write to
141 * \param[in] pbc The periodic boundary condition information structure
143 void dump_pbc(FILE* fp, t_pbc* pbc);
145 /*! \brief Check the box for consistency
147 * \param[in] ePBC The pbc identifier
148 * \param[in] box The box matrix
149 * \return NULL if the box is supported by Gromacs.
150 * Otherwise returns a string with the problem.
151 * When ePBC=-1, the type of pbc is guessed from the box matrix.
153 const char* check_box(int ePBC, const matrix box);
155 /*! \brief Creates box matrix from edge lengths and angles.
157 * \param[in,out] box The box matrix
158 * \param[in] vec The edge lengths
159 * \param[in] angleInDegrees The angles
161 void matrix_convert(matrix box, const rvec vec, const rvec angleInDegrees);
163 /*! \brief Compute the maximum cutoff for the box
165 * Returns the square of the maximum cut-off allowed for the box,
166 * taking into account that the grid neighborsearch code and pbc_dx
167 * only check combinations of single box-vector shifts.
168 * \param[in] ePBC The pbc identifier
169 * \param[in] box The box matrix
170 * \return the maximum cut-off.
172 real max_cutoff2(int ePBC, const matrix box);
174 /*! \brief Guess PBC typr
176 * Guesses the type of periodic boundary conditions using the box
177 * \param[in] box The box matrix
178 * \return The pbc identifier
180 int guess_ePBC(const matrix box);
182 /*! \brief Corrects the box if necessary
184 * Checks for un-allowed box angles and corrects the box
185 * and the integer shift vectors in the graph (if graph!=NULL) if necessary.
186 * \param[in] fplog File for debug output
187 * \param[in] step The MD step number
188 * \param[in] box The simulation cell
189 * \param[in] graph Information about molecular connectivity
190 * \return TRUE when the box was corrected.
192 gmx_bool correct_box(FILE* fplog, int step, tensor box, struct t_graph* graph);
194 /*! \brief Initiate the periodic boundary condition algorithms.
196 * pbc_dx will not use pbc and return the normal difference vector
197 * when one or more of the diagonal elements of box are zero.
198 * When ePBC=-1, the type of pbc is guessed from the box matrix.
199 * \param[in,out] pbc The pbc information structure
200 * \param[in] ePBC The PBC identifier
201 * \param[in] box The box tensor
203 void set_pbc(t_pbc* pbc, int ePBC, const matrix box);
205 /*! \brief Initiate the periodic boundary condition algorithms.
207 * As set_pbc, but additionally sets that correct distances can
208 * be obtained using (combinations of) single box-vector shifts.
209 * Should be used with pbc_dx_aiuc.
210 * If domdecCells!=NULL pbc is not used for directions
211 * with dd->nc[i]==1 with bSingleDir==TRUE or
212 * with dd->nc[i]<=2 with bSingleDir==FALSE.
213 * Note that when no PBC is required only pbc->ePBC is set,
214 * the rest of the struct will be invalid.
215 * \param[in,out] pbc The pbc information structure
216 * \param[in] ePBC The PBC identifier
217 * \param[in] domdecCells 3D integer vector describing the number of DD cells
218 * or nullptr if not using DD.
219 * \param[in] bSingleDir TRUE if DD communicates only in one direction along dimensions
220 * \param[in] box The box tensor
221 * \return the pbc structure when pbc operations are required, NULL otherwise.
223 t_pbc* set_pbc_dd(t_pbc* pbc, int ePBC, const ivec domdecCells, gmx_bool bSingleDir, const matrix box);
225 /*! \brief Compute distance with PBC
227 * Calculate the correct distance vector from x2 to x1 and put it in dx.
228 * set_pbc must be called before ever calling this routine.
230 * Note that for triclinic boxes that do not obey the GROMACS unit-cell
231 * restrictions, pbc_dx and pbc_dx_aiuc will not correct for PBC.
232 * \param[in,out] pbc The pbc information structure
233 * \param[in] x1 Coordinates for particle 1
234 * \param[in] x2 Coordinates for particle 2
235 * \param[out] dx Distance vector
237 void pbc_dx(const t_pbc* pbc, const rvec x1, const rvec x2, rvec dx);
239 /*! \brief Compute distance vector for simple PBC types
241 * Calculate the correct distance vector from x2 to x1 and put it in dx,
242 * This function can only be used when all atoms are in the rectangular
243 * or triclinic unit-cell.
244 * set_pbc_dd or set_pbc must be called before ever calling this routine.
245 * \param[in,out] pbc The pbc information structure
246 * \param[in] x1 Coordinates for particle 1
247 * \param[in] x2 Coordinates for particle 2
248 * \param[out] dx Distance vector
249 * \return the ishift required to shift x1 at closest distance to x2;
250 * i.e. if 0<=ishift<SHIFTS then x1 - x2 + shift_vec[ishift] = dx
251 * (see calc_shifts below on how to obtain shift_vec)
253 int pbc_dx_aiuc(const t_pbc* pbc, const rvec x1, const rvec x2, rvec dx);
255 /*! \brief Compute distance with PBC
257 * As pbc_dx, but for double precision vectors.
258 * set_pbc must be called before ever calling this routine.
259 * \param[in,out] pbc The pbc information structure
260 * \param[in] x1 Coordinates for particle 1
261 * \param[in] x2 Coordinates for particle 2
262 * \param[out] dx Distance vector
264 void pbc_dx_d(const t_pbc* pbc, const dvec x1, const dvec x2, dvec dx);
266 /*! \brief Computes shift vectors
268 * This routine calculates ths shift vectors necessary to use the
269 * neighbor searching routine.
270 * \param[in] box The simulation box
271 * \param[out] shift_vec The shifting vectors
273 void calc_shifts(const matrix box, rvec shift_vec[]);
275 /*! \brief Calculates the center of the box.
277 * See the description for the enum ecenter above.
278 * \param[in] ecenter Description of center type
279 * \param[in] box The simulation box
280 * \param[out] box_center The center of the box
282 void calc_box_center(int ecenter, const matrix box, rvec box_center);
284 /*! \brief Calculates the NTRICIMG box images
286 * \param[in] box The simulation box
287 * \param[out] img The triclinic box images
289 void calc_triclinic_images(const matrix box, rvec img[]);
291 /*! \brief Calculates the NCUCVERT vertices of a compact unitcell
293 * \param[in] ecenter The center type
294 * \param[in] box The simulation box
295 * \param[out] vert The vertices
297 void calc_compact_unitcell_vertices(int ecenter, const matrix box, rvec vert[]);
299 /*! \brief Compute unitcell edges
301 * \return an array of unitcell edges of length NCUCEDGE*2,
302 * this is an index in vert[], which is calculated by calc_unitcell_vertices.
303 * The index consists of NCUCEDGE pairs of vertex indices.
304 * The index does not change, so it needs to be retrieved only once.
306 int* compact_unitcell_edges();
308 /*! \brief Put atoms inside the simulations box
310 * These routines puts ONE or ALL atoms in the box, not caring
311 * about charge groups!
312 * Also works for triclinic cells.
313 * \param[in] ePBC The pbc type
314 * \param[in] box The simulation box
315 * \param[in,out] x The coordinates of the atoms
317 void put_atoms_in_box(int ePBC, const matrix box, gmx::ArrayRef<gmx::RVec> x);
319 /*! \brief Parallellizes put_atoms_in_box()
321 * This wrapper function around put_atoms_in_box() with the ugly manual
322 * workload splitting is needed to avoid silently introducing multithreading
324 * \param[in] ePBC The pbc type
325 * \param[in] box The simulation box
326 * \param[in,out] x The coordinates of the atoms
327 * \param[in] nth number of threads to be used in the given module
329 void put_atoms_in_box_omp(int ePBC, const matrix box, gmx::ArrayRef<gmx::RVec> x, gmx_unused int nth);
331 /*! \brief Put atoms inside triclinic box
333 * This puts ALL atoms in the triclinic unit cell, centered around the
334 * box center as calculated by calc_box_center.
335 * \param[in] ecenter The pbc center type
336 * \param[in] box The simulation box
337 * \param[in,out] x The coordinates of the atoms
339 void put_atoms_in_triclinic_unitcell(int ecenter, const matrix box, gmx::ArrayRef<gmx::RVec> x);
341 /*! \brief Put atoms inside the unitcell
343 * This puts ALL atoms at the closest distance for the center of the box
344 * as calculated by calc_box_center.
345 * When ePBC=-1, the type of pbc is guessed from the box matrix.
346 * \param[in] ePBC The pbc type
347 * \param[in] ecenter The pbc center type
348 * \param[in] box The simulation box
349 * \param[in,out] x The coordinates of the atoms
351 void put_atoms_in_compact_unitcell(int ePBC, int ecenter, const matrix box, gmx::ArrayRef<gmx::RVec> x);
353 /*! \brief Make all molecules whole by shifting positions
355 * \param[in] fplog Log file
356 * \param[in] ePBC The PBC type
357 * \param[in] box The simulation box
358 * \param[in] mtop System topology definition
359 * \param[in,out] x The coordinates of the atoms
361 void do_pbc_first_mtop(FILE* fplog, int ePBC, const matrix box, const gmx_mtop_t* mtop, rvec x[]);
363 /*! \brief Make molecules consisting of multiple charge groups whole by shifting positions
365 * \param[in] ePBC The PBC type
366 * \param[in] box The simulation box
367 * \param[in] mtop System topology definition
368 * \param[in,out] x The coordinates of the atoms
370 void do_pbc_mtop(int ePBC, const matrix box, const gmx_mtop_t* mtop, rvec x[]);