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38 #ifndef GMX_PBCUTIL_PBC_H
39 #define GMX_PBCUTIL_PBC_H
45 #include "gromacs/math/vectypes.h"
46 #include "gromacs/mdtypes/md_enums.h"
47 #include "gromacs/utility/basedefinitions.h"
48 #include "gromacs/utility/enumerationhelpers.h"
49 #include "gromacs/utility/real.h"
60 //! Names for all values in PBC types enumeration
61 extern const gmx::EnumerationArray<PbcType, std::string> c_pbcTypeNames;
63 /* Maximum number of combinations of single triclinic box vectors
64 * required to shift atoms that are within a brick of the size of
65 * the diagonal of the box to within the maximum cut-off distance.
67 #define MAX_NTRICVEC 12
69 /*! \brief Structure containing info on periodic boundary conditions */
74 //! Number of dimensions in which PBC is exerted
76 /*! \brief Determines how to compute distance vectors.
78 * Indicator of how to compute distance vectors, depending
79 * on PBC type (depends on pbcType and dimensions with(out) DD)
83 /*! \brief Used for selecting which dimensions to use in PBC.
85 * In case of 1-D PBC this indicates which dimension is used,
86 * in case of 2-D PBC this indicates the opposite
89 //! The simulation box
91 //! The lengths of the diagonal of the full box
93 //! Halve of the above
95 //! Negative of the above
97 //! Maximum allowed cutoff squared for the box and PBC used
99 /*! \brief Number of triclinic shift vectors.
101 * Number of triclinic shift vectors depends on the skewedness
102 * of the box, that is mostly on the angles. For triclinic boxes
103 * we first take the closest image along each Cartesian dimension
104 * independently. When the resulting distance^2 is larger than
105 * max_cutoff2, up to ntric_vec triclinic shift vectors need to
106 * be tried. Because of the restrictions imposed on the unit-cell
107 * by GROMACS, ntric_vec <= MAX_NTRICVEC = 12.
110 //! The triclinic shift vectors in grid cells. Internal use only.
111 ivec tric_shift[MAX_NTRICVEC];
112 //! The triclinic shift vectors in length units
113 rvec tric_vec[MAX_NTRICVEC];
116 #define TRICLINIC(box) ((box)[YY][XX] != 0 || (box)[ZZ][XX] != 0 || (box)[ZZ][YY] != 0)
124 ecenterTRIC, /* 0.5*(a+b+c) */
125 ecenterRECT, /* (0.5*a[x],0.5*b[y],0.5*c[z]) */
126 ecenterZERO, /* (0,0,0) */
127 ecenterDEF = ecenterTRIC
130 /*! \brief Returns the number of dimensions that use pbc
132 * \param[in] pbcType The periodic boundary condition type
133 * \return the number of dimensions that use pbc, starting at X
135 int numPbcDimensions(PbcType pbcType);
137 /*! \brief Dump the contents of the pbc structure to the file
139 * \param[in] fp The file pointer to write to
140 * \param[in] pbc The periodic boundary condition information structure
142 void dump_pbc(FILE* fp, t_pbc* pbc);
144 /*! \brief Check the box for consistency
146 * When \p pbcType=PbcTypes::Unset, the type of pbc is guessed from the box matrix.
148 * \param[in] pbcType The pbc identifier
149 * \param[in] box The box matrix
150 * \return NULL if the box is supported by Gromacs.
151 * Otherwise returns a string with the problem.
153 const char* check_box(PbcType pbcType, 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.
169 * \param[in] pbcType The pbc identifier
170 * \param[in] box The box matrix
171 * \return the maximum cut-off.
173 real max_cutoff2(PbcType pbcType, const matrix box);
175 /*! \brief Guess PBC type
177 * Guesses the type of periodic boundary conditions using the box
179 * \param[in] box The box matrix
180 * \return The pbc type identifier
182 PbcType guessPbcType(const matrix box);
184 /*! \brief Corrects the box if necessary
186 * Checks for un-allowed box angles and corrects the box.
188 * \param[in] fplog File for debug output
189 * \param[in] step The MD step number
190 * \param[in] box The simulation cell
191 * \return TRUE when the box was corrected.
193 bool correct_box(FILE* fplog, int step, tensor box);
195 /*! \brief Initiate the periodic boundary condition algorithms.
197 * pbc_dx will not use pbc and return the normal difference vector
198 * when one or more of the diagonal elements of box are zero.
199 * When \p pbcType=PbcType::Unset, the type of pbc is guessed from the box matrix.
201 * \param[in,out] pbc The pbc information structure
202 * \param[in] pbcType The PBC identifier
203 * \param[in] box The box tensor
205 void set_pbc(t_pbc* pbc, PbcType pbcType, const matrix box);
207 /*! \brief Initiate the periodic boundary condition algorithms.
209 * As set_pbc, but additionally sets that correct distances can
210 * be obtained using (combinations of) single box-vector shifts.
211 * Should be used with pbc_dx_aiuc.
212 * If domdecCells!=NULL pbc is not used for directions
213 * with dd->nc[i]==1 with bSingleDir==TRUE or
214 * with dd->nc[i]<=2 with bSingleDir==FALSE.
215 * Note that when no PBC is required only pbc->pbcType is set,
216 * the rest of the struct will be invalid.
218 * \param[in,out] pbc The pbc information structure
219 * \param[in] pbcType The PBC identifier
220 * \param[in] domdecCells 3D integer vector describing the number of DD cells
221 * or nullptr if not using DD.
222 * \param[in] bSingleDir TRUE if DD communicates only in one direction along dimensions
223 * \param[in] box The box tensor
224 * \return the pbc structure when pbc operations are required, NULL otherwise.
226 t_pbc* set_pbc_dd(t_pbc* pbc, PbcType pbcType, const ivec domdecCells, bool bSingleDir, const matrix box);
228 /*! \brief Compute distance with PBC
230 * Calculate the correct distance vector from x2 to x1 and put it in dx.
231 * set_pbc must be called before ever calling this routine.
233 * Note that for triclinic boxes that do not obey the GROMACS unit-cell
234 * restrictions, pbc_dx and pbc_dx_aiuc will not correct for PBC.
235 * \param[in,out] pbc The pbc information structure
236 * \param[in] x1 Coordinates for particle 1
237 * \param[in] x2 Coordinates for particle 2
238 * \param[out] dx Distance vector
240 void pbc_dx(const t_pbc* pbc, const rvec x1, const rvec x2, rvec dx);
242 /*! \brief Compute distance vector for simple PBC types
244 * Calculate the correct distance vector from x2 to x1 and put it in dx,
245 * This function can only be used when all atoms are in the rectangular
246 * or triclinic unit-cell.
247 * set_pbc_dd or set_pbc must be called before ever calling this routine.
248 * \param[in,out] pbc The pbc information structure
249 * \param[in] x1 Coordinates for particle 1
250 * \param[in] x2 Coordinates for particle 2
251 * \param[out] dx Distance vector
252 * \return the ishift required to shift x1 at closest distance to x2;
253 * i.e. if 0<=ishift<c_numShiftVectors then x1 - x2 + shift_vec[ishift] = dx
254 * (see calc_shifts below on how to obtain shift_vec)
256 int pbc_dx_aiuc(const t_pbc* pbc, const rvec x1, const rvec x2, rvec dx);
258 /*! \brief Compute distance with PBC
260 * As pbc_dx, but for double precision vectors.
261 * set_pbc must be called before ever calling this routine.
262 * \param[in,out] pbc The pbc information structure
263 * \param[in] x1 Coordinates for particle 1
264 * \param[in] x2 Coordinates for particle 2
265 * \param[out] dx Distance vector
267 void pbc_dx_d(const t_pbc* pbc, const dvec x1, const dvec x2, dvec dx);
269 /*! \brief Computes shift vectors
271 * This routine calculates ths shift vectors necessary to use the
272 * neighbor searching routine.
273 * \param[in] box The simulation box
274 * \param[out] shift_vec The shifting vectors
276 void calc_shifts(const matrix box, gmx::ArrayRef<gmx::RVec> shift_vec);
278 /*! \brief Calculates the center of the box.
280 * See the description for the enum ecenter above.
281 * \param[in] ecenter Description of center type
282 * \param[in] box The simulation box
283 * \param[out] box_center The center of the box
285 void calc_box_center(int ecenter, const matrix box, rvec box_center);
287 /*! \brief Calculates the NTRICIMG box images
289 * \param[in] box The simulation box
290 * \param[out] img The triclinic box images
292 void calc_triclinic_images(const matrix box, rvec img[]);
294 /*! \brief Calculates the NCUCVERT vertices of a compact unitcell
296 * \param[in] ecenter The center type
297 * \param[in] box The simulation box
298 * \param[out] vert The vertices
300 void calc_compact_unitcell_vertices(int ecenter, const matrix box, rvec vert[]);
302 /*! \brief Compute unitcell edges
304 * \return an array of unitcell edges of length NCUCEDGE*2,
305 * this is an index in vert[], which is calculated by calc_unitcell_vertices.
306 * The index consists of NCUCEDGE pairs of vertex indices.
307 * The index does not change, so it needs to be retrieved only once.
309 int* compact_unitcell_edges();
311 /*! \brief Put atoms inside the simulations box
313 * These routines puts ONE or ALL atoms in the box, not caring
314 * about charge groups!
315 * Also works for triclinic cells.
317 * \param[in] pbcType The pbc type
318 * \param[in] box The simulation box
319 * \param[in,out] x The coordinates of the atoms
321 void put_atoms_in_box(PbcType pbcType, const matrix box, gmx::ArrayRef<gmx::RVec> x);
323 /*! \brief Parallellizes put_atoms_in_box()
325 * This wrapper function around put_atoms_in_box() with the ugly manual
326 * workload splitting is needed to avoid silently introducing multithreading
329 * \param[in] pbcType The pbc type
330 * \param[in] box The simulation box
331 * \param[in,out] x The coordinates of the atoms
332 * \param[in] nth number of threads to be used in the given module
334 void put_atoms_in_box_omp(PbcType pbcType, const matrix box, gmx::ArrayRef<gmx::RVec> x, gmx_unused int nth);
336 /*! \brief Put atoms inside triclinic box
338 * This puts ALL atoms in the triclinic unit cell, centered around the
339 * box center as calculated by calc_box_center.
340 * \param[in] ecenter The pbc center type
341 * \param[in] box The simulation box
342 * \param[in,out] x The coordinates of the atoms
344 void put_atoms_in_triclinic_unitcell(int ecenter, const matrix box, gmx::ArrayRef<gmx::RVec> x);
346 /*! \brief Put atoms inside the unitcell
348 * This puts ALL atoms at the closest distance for the center of the box
349 * as calculated by calc_box_center.
350 * When \p pbcType=PbcType::Unset, the type of pbc is guessed from the box matrix.
352 * \param[in] pbcType The pbc type
353 * \param[in] ecenter The pbc center type
354 * \param[in] box The simulation box
355 * \param[in,out] x The coordinates of the atoms
357 void put_atoms_in_compact_unitcell(PbcType pbcType, int ecenter, const matrix box, gmx::ArrayRef<gmx::RVec> x);
359 /*! \brief Make all molecules whole by shifting positions
361 * \param[in] fplog Log file
362 * \param[in] pbcType The PBC type
363 * \param[in] box The simulation box
364 * \param[in] mtop System topology definition
365 * \param[in,out] x The coordinates of the atoms
367 void do_pbc_first_mtop(FILE* fplog, PbcType pbcType, const matrix box, const gmx_mtop_t* mtop, rvec x[]);
369 /*! \brief Make molecules consisting of multiple charge groups whole by shifting positions
371 * \param[in] pbcType The PBC type
372 * \param[in] box The simulation box
373 * \param[in] mtop System topology definition
374 * \param[in,out] x The coordinates of the atoms
376 void do_pbc_mtop(PbcType pbcType, const matrix box, const gmx_mtop_t* mtop, rvec x[]);