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37 * Declares gmx::Selection and supporting classes.
39 * \author Teemu Murtola <teemu.murtola@gmail.com>
41 * \ingroup module_selection
43 #ifndef GMX_SELECTION_SELECTION_H
44 #define GMX_SELECTION_SELECTION_H
49 #include "gromacs/utility/arrayref.h"
50 #include "gromacs/utility/classhelpers.h"
51 #include "gromacs/utility/gmxassert.h"
54 #include "selectionenums.h"
61 class SelectionOptionStorage;
62 class SelectionTreeElement;
64 class AnalysisNeighborhoodPositions;
66 class SelectionPosition;
68 //! Container of selections used in public selection interfaces.
69 typedef std::vector<Selection> SelectionList;
76 * Internal data for a single selection.
78 * This class is internal to the selection module, but resides in a public
79 * header because of efficiency reasons: it allows frequently used access
80 * methods in \ref Selection to be inlined.
82 * Methods in this class do not throw unless otherwise specified.
84 * \ingroup module_selection
90 * Creates a new selection object.
92 * \param[in] elem Root of the evaluation tree for this selection.
93 * \param[in] selstr String that was parsed to produce this selection.
94 * \throws std::bad_alloc if out of memory.
96 SelectionData(SelectionTreeElement* elem, const char* selstr);
99 //! Returns the name for this selection.
100 const char* name() const { return name_.c_str(); }
101 //! Returns the string that was parsed to produce this selection.
102 const char* selectionText() const { return selectionText_.c_str(); }
103 //! Returns true if the size of the selection (posCount()) is dynamic.
104 bool isDynamic() const { return bDynamic_; }
105 //! Returns the type of positions in the selection.
106 e_index_t type() const { return rawPositions_.m.type; }
107 //! Returns true if the selection only contains positions with a single atom each.
108 bool hasOnlyAtoms() const { return type() == INDEX_ATOM; }
109 //! Returns `true` if the atom indices in the selection are in ascending order.
110 bool hasSortedAtomIndices() const;
112 //! Number of positions in the selection.
113 int posCount() const { return rawPositions_.count(); }
114 //! Returns the root of the evaluation tree for this selection.
115 SelectionTreeElement& rootElement() { return rootElement_; }
117 //! Returns whether the covered fraction can change between frames.
118 bool isCoveredFractionDynamic() const { return bDynamicCoveredFraction_; }
120 //! Returns true if the given flag is set.
121 bool hasFlag(SelectionFlag flag) const { return flags_.test(flag); }
122 //! Sets the flags for this selection.
123 void setFlags(SelectionFlags flags) { flags_ = flags; }
125 //! \copydoc Selection::initCoveredFraction()
126 bool initCoveredFraction(e_coverfrac_t type);
129 * Updates the name of the selection if missing.
131 * \throws std::bad_alloc if out of memory.
133 * If selections get their value from a group reference that cannot be
134 * resolved during parsing, the name is final only after group
135 * references have been resolved.
137 * This function is called by SelectionCollection::setIndexGroups().
141 * Computes total masses and charges for all selection positions.
143 * \param[in] top Topology information.
144 * \throws std::bad_alloc if out of memory.
146 * For dynamic selections, the values need to be updated after each
147 * evaluation with refreshMassesAndCharges().
148 * This is done by SelectionEvaluator.
150 * This function is called by SelectionCompiler.
152 * Strong exception safety guarantee.
154 void initializeMassesAndCharges(const gmx_mtop_t* top);
156 * Updates masses and charges after dynamic selection has been
159 * \param[in] top Topology information.
161 * Called by SelectionEvaluator.
163 void refreshMassesAndCharges(const gmx_mtop_t* top);
165 * Updates the covered fraction after a selection has been evaluated.
167 * Called by SelectionEvaluator.
169 void updateCoveredFractionForFrame();
171 * Computes average covered fraction after all frames have been evaluated.
173 * \param[in] nframes Number of frames that have been evaluated.
175 * \p nframes should be equal to the number of calls to
176 * updateCoveredFractionForFrame().
177 * Called by SelectionEvaluator::evaluateFinal().
179 void computeAverageCoveredFraction(int nframes);
181 * Restores position information to state it was in after compilation.
183 * \param[in] top Topology information.
185 * Depends on SelectionCompiler storing the original atoms in the
186 * \a rootElement_ object.
187 * Called by SelectionEvaluator::evaluateFinal().
189 void restoreOriginalPositions(const gmx_mtop_t* top);
192 //! Name of the selection.
194 //! The actual selection string.
195 std::string selectionText_;
196 //! Low-level representation of selected positions.
197 gmx_ana_pos_t rawPositions_;
198 //! Total masses for the current positions.
199 std::vector<real> posMass_;
200 //! Total charges for the current positions.
201 std::vector<real> posCharge_;
202 SelectionFlags flags_;
203 //! Root of the selection evaluation tree.
204 SelectionTreeElement& rootElement_;
205 //! Type of the covered fraction.
206 e_coverfrac_t coveredFractionType_;
207 //! Covered fraction of the selection for the current frame.
208 real coveredFraction_;
209 //! The average covered fraction (over the trajectory).
210 real averageCoveredFraction_;
211 //! true if the value can change as a function of time.
213 //! true if the covered fraction depends on the frame.
214 bool bDynamicCoveredFraction_;
217 * Needed to wrap access to information.
219 friend class gmx::Selection;
221 * Needed for proper access to position information.
223 friend class gmx::SelectionPosition;
225 GMX_DISALLOW_COPY_AND_ASSIGN(SelectionData);
228 } // namespace internal
231 * Provides access to a single selection.
233 * This class provides a public interface for accessing selection information.
234 * General information about the selection can be accessed with methods name(),
235 * selectionText(), isDynamic(), and type(). The first three can be accessed
236 * any time after the selection has been parsed, and type() can be accessed
237 * after the selection has been compiled.
239 * There are a few methods that can be used to change the behavior of the
240 * selection. setEvaluateVelocities() and setEvaluateForces() can be called
241 * before the selection is compiled to request evaluation of velocities and/or
242 * forces in addition to coordinates.
244 * Each selection is made of a set of positions. Each position has associated
245 * coordinates, and possibly velocities and forces if they have been requested
246 * and are available. It also has a set of atoms associated with it; typically
247 * the coordinates are the center-of-mass or center-of-geometry coordinates for
248 * that set of atoms. To access the number of positions in the selection, use
249 * posCount(). To access individual positions, use position().
250 * See SelectionPosition for details of how to use individual positions.
251 * setOriginalId() can be used to adjust the return value of
252 * SelectionPosition::mappedId(); see that method for details.
254 * It is also possible to access the list of atoms that make up all the
255 * positions directly: atomCount() returns the total number of atoms in the
256 * selection and atomIndices() an array of their indices.
257 * Similarly, it is possible to access the coordinates and other properties
258 * of the positions as continuous arrays through coordinates(), velocities(),
259 * forces(), masses(), charges(), refIds(), and mappedIds().
261 * Both positions and atoms can be accessed after the selection has been
262 * compiled. For dynamic selections, the return values of these methods change
263 * after each evaluation to reflect the situation for the current frame.
264 * Before any frame has been evaluated, these methods return the maximal set
265 * to which the selection can evaluate.
267 * There are two possible modes for how positions for dynamic selections are
268 * handled. In the default mode, posCount() can change, and for each frame,
269 * only the positions that are selected in that frame can be accessed. In a
270 * masked mode, posCount() remains constant, i.e., the positions are always
271 * evaluated for the maximal set, and SelectionPosition::selected() is used to
272 * determine whether a position is selected for a frame. The masked mode can
273 * be requested with SelectionOption::dynamicMask().
275 * The class also provides methods for printing out information: printInfo()
276 * and printDebugInfo(). These are mainly for internal use by Gromacs.
278 * This class works like a pointer type: copying and assignment is lightweight,
279 * and all copies work interchangeably, accessing the same internal data.
281 * Methods in this class do not throw.
283 * \see SelectionPosition
286 * \ingroup module_selection
292 * Creates a selection wrapper that has no associated selection.
294 * Any attempt to call methods in the object before a selection is
295 * assigned results in undefined behavior.
296 * isValid() returns `false` for the selection until it is initialized.
298 Selection() : sel_(nullptr) {}
300 * Creates a new selection object.
302 * \param sel Selection data to wrap.
304 * Only for internal use by the selection module.
306 explicit Selection(internal::SelectionData* sel) : sel_(sel) {}
308 //! Returns whether the selection object is initialized.
309 bool isValid() const { return sel_ != nullptr; }
311 //! Returns whether two selection objects wrap the same selection.
312 bool operator==(const Selection& other) const { return sel_ == other.sel_; }
313 //! Returns whether two selection objects wrap different selections.
314 bool operator!=(const Selection& other) const { return !operator==(other); }
316 //! Returns the name of the selection.
317 const char* name() const { return data().name(); }
318 //! Returns the string that was parsed to produce this selection.
319 const char* selectionText() const { return data().selectionText(); }
320 //! Returns true if the size of the selection (posCount()) is dynamic.
321 bool isDynamic() const { return data().isDynamic(); }
322 //! Returns the type of positions in the selection.
323 e_index_t type() const { return data().type(); }
324 //! Returns true if the selection only contains positions with a single atom each.
325 bool hasOnlyAtoms() const { return data().hasOnlyAtoms(); }
326 //! Returns `true` if the atom indices in the selection are in ascending order.
327 bool hasSortedAtomIndices() const { return data().hasSortedAtomIndices(); }
329 //! Total number of atoms in the selection.
330 int atomCount() const { return data().rawPositions_.m.mapb.nra; }
331 //! Returns atom indices of all atoms in the selection.
332 ArrayRef<const int> atomIndices() const
334 return constArrayRefFromArray(sel_->rawPositions_.m.mapb.a, sel_->rawPositions_.m.mapb.nra);
336 //! Number of positions in the selection.
337 int posCount() const { return data().posCount(); }
338 //! Access a single position.
339 SelectionPosition position(int i) const;
340 //! Returns coordinates for this selection as a continuous array.
341 ArrayRef<const rvec> coordinates() const
343 return constArrayRefFromArray(data().rawPositions_.x, posCount());
345 //! Returns whether velocities are available for this selection.
346 bool hasVelocities() const { return data().rawPositions_.v != nullptr; }
348 * Returns velocities for this selection as a continuous array.
350 * Must not be called if hasVelocities() returns false.
352 ArrayRef<const rvec> velocities() const
354 GMX_ASSERT(hasVelocities(), "Velocities accessed, but unavailable");
355 return constArrayRefFromArray(data().rawPositions_.v, posCount());
357 //! Returns whether forces are available for this selection.
358 bool hasForces() const { return sel_->rawPositions_.f != nullptr; }
360 * Returns forces for this selection as a continuous array.
362 * Must not be called if hasForces() returns false.
364 ArrayRef<const rvec> forces() const
366 GMX_ASSERT(hasForces(), "Forces accessed, but unavailable");
367 return constArrayRefFromArray(data().rawPositions_.f, posCount());
369 //! Returns masses for this selection as a continuous array.
370 ArrayRef<const real> masses() const
372 // posMass_ may have more entries than posCount() in the case of
373 // dynamic selections that don't have a topology
374 // (and thus the masses and charges are fixed).
375 GMX_ASSERT(data().posMass_.size() >= static_cast<size_t>(posCount()),
376 "Internal inconsistency");
377 return makeArrayRef(data().posMass_).subArray(0, posCount());
379 //! Returns charges for this selection as a continuous array.
380 ArrayRef<const real> charges() const
382 // posCharge_ may have more entries than posCount() in the case of
383 // dynamic selections that don't have a topology
384 // (and thus the masses and charges are fixed).
385 GMX_ASSERT(data().posCharge_.size() >= static_cast<size_t>(posCount()),
386 "Internal inconsistency");
387 return makeArrayRef(data().posCharge_).subArray(0, posCount());
390 * Returns reference IDs for this selection as a continuous array.
392 * \see SelectionPosition::refId()
394 ArrayRef<const int> refIds() const
396 return constArrayRefFromArray(data().rawPositions_.m.refid, posCount());
399 * Returns mapped IDs for this selection as a continuous array.
401 * \see SelectionPosition::mappedId()
403 ArrayRef<const int> mappedIds() const
405 return constArrayRefFromArray(data().rawPositions_.m.mapid, posCount());
408 //! Returns whether the covered fraction can change between frames.
409 bool isCoveredFractionDynamic() const { return data().isCoveredFractionDynamic(); }
410 //! Returns the covered fraction for the current frame.
411 real coveredFraction() const { return data().coveredFraction_; }
414 * Allows passing a selection directly to neighborhood searching.
416 * When initialized this way, AnalysisNeighborhoodPair objects return
417 * indices that can be used to index the selection positions with
420 * Works exactly like if AnalysisNeighborhoodPositions had a
421 * constructor taking a Selection object as a parameter.
422 * See AnalysisNeighborhoodPositions for rationale and additional
425 operator AnalysisNeighborhoodPositions() const;
428 * Initializes information about covered fractions.
430 * \param[in] type Type of covered fraction required.
431 * \returns true if the covered fraction can be calculated for the
434 bool initCoveredFraction(e_coverfrac_t type) { return data().initCoveredFraction(type); }
436 * Sets whether this selection evaluates velocities for positions.
438 * \param[in] bEnabled If true, velocities are evaluated.
440 * If you request the evaluation, but then evaluate the selection for
441 * a frame that does not contain velocity information, results are
445 * Implement it such that in the above case, hasVelocities() will
446 * return false for such frames.
450 void setEvaluateVelocities(bool bEnabled)
452 data().flags_.set(efSelection_EvaluateVelocities, bEnabled);
455 * Sets whether this selection evaluates forces for positions.
457 * \param[in] bEnabled If true, forces are evaluated.
459 * If you request the evaluation, but then evaluate the selection for
460 * a frame that does not contain force information, results are
465 void setEvaluateForces(bool bEnabled)
467 data().flags_.set(efSelection_EvaluateForces, bEnabled);
471 * Sets the ID for the \p i'th position for use with
472 * SelectionPosition::mappedId().
474 * \param[in] i Zero-based index
475 * \param[in] id Identifier to set.
477 * This method is not part of SelectionPosition because that interface
478 * only provides access to const data by design.
480 * This method can only be called after compilation, before the
481 * selection has been evaluated for any frame.
483 * \see SelectionPosition::mappedId()
485 void setOriginalId(int i, int id);
487 * Inits the IDs for use with SelectionPosition::mappedId() for
490 * \param[in] top Topology information
491 * (can be NULL if not required for \p type).
492 * \param[in] type Type of groups to generate.
493 * \returns Number of groups that were present in the selection.
494 * \throws InconsistentInputError if the selection positions cannot
495 * be assigned to groups of the given type.
497 * If `type == INDEX_ATOM`, the IDs are initialized to 0, 1, 2, ...,
498 * and the return value is the number of positions.
499 * If `type == INDEX_ALL`, all the IDs are initialized to 0, and the
500 * return value is one.
501 * If `type == INDEX_RES` or `type == INDEX_MOL`, the first position
502 * will get ID 0, and all following positions that belong to the same
503 * residue/molecule will get the same ID. The first position that
504 * belongs to a different residue/molecule will get ID 1, and so on.
505 * If some position contains atoms from multiple residues/molecules,
506 * i.e., the mapping is ambiguous, an exception is thrown.
507 * The return value is the number of residues/molecules that are
508 * present in the selection positions.
510 * This method is useful if the calling code needs to group the
511 * selection, e.g., for computing aggregate properties for each residue
512 * or molecule. It can then use this method to initialize the
513 * appropriate grouping, use the return value to allocate a
514 * sufficiently sized buffer to store the aggregated values, and then
515 * use SelectionPosition::mappedId() to identify the location where to
518 * \see setOriginalId()
519 * \see SelectionPosition::mappedId()
521 int initOriginalIdsToGroup(const gmx_mtop_t* top, e_index_t type);
524 * Prints out one-line description of the selection.
526 * \param[in] fp Where to print the information.
528 * The output contains the name of the selection, the number of atoms
529 * and the number of positions, and indication of whether the selection
532 void printInfo(FILE* fp) const;
534 * Prints out extended information about the selection for debugging.
536 * \param[in] fp Where to print the information.
537 * \param[in] nmaxind Maximum number of values to print in lists
540 void printDebugInfo(FILE* fp, int nmaxind) const;
543 internal::SelectionData& data()
545 GMX_ASSERT(sel_ != nullptr, "Attempted to access uninitialized selection");
548 const internal::SelectionData& data() const
550 GMX_ASSERT(sel_ != nullptr, "Attempted to access uninitialized selection");
555 * Pointer to internal data for the selection.
557 * The memory for this object is managed by a SelectionCollection
558 * object, and the \ref Selection class simply provides a public
559 * interface for accessing the data.
561 internal::SelectionData* sel_;
564 * Needed to access the data to adjust flags.
566 friend class SelectionOptionStorage;
570 * Provides access to information about a single selected position.
572 * Each position has associated coordinates, and possibly velocities and forces
573 * if they have been requested and are available. It also has a set of atoms
574 * associated with it; typically the coordinates are the center-of-mass or
575 * center-of-geometry coordinates for that set of atoms. It is possible that
576 * there are not atoms associated if the selection has been provided as a fixed
579 * After the selection has been compiled, but not yet evaluated, the contents
580 * of the coordinate, velocity and force vectors are undefined.
582 * Default copy constructor and assignment operators are used, and work as
583 * intended: the copy references the same position and works identically.
585 * Methods in this class do not throw.
590 * \ingroup module_selection
592 class SelectionPosition
596 * Constructs a wrapper object for given selection position.
598 * \param[in] sel Selection from which the position is wrapped.
599 * \param[in] index Zero-based index of the position to wrap.
601 * Asserts if \p index is out of range.
603 * Only for internal use of the library. To obtain a SelectionPosition
604 * object in other code, use Selection::position().
606 SelectionPosition(const internal::SelectionData& sel, int index) : sel_(&sel), i_(index)
608 GMX_ASSERT(index >= 0 && index < sel.posCount(), "Invalid selection position index");
612 * Returns type of this position.
614 * Currently always returns the same as Selection::type().
616 e_index_t type() const { return sel_->type(); }
617 //! Returns coordinates for this position.
618 const rvec& x() const { return sel_->rawPositions_.x[i_]; }
620 * Returns velocity for this position.
622 * Must not be called if Selection::hasVelocities() returns false.
624 const rvec& v() const
626 GMX_ASSERT(sel_->rawPositions_.v != nullptr, "Velocities accessed, but unavailable");
627 return sel_->rawPositions_.v[i_];
630 * Returns force for this position.
632 * Must not be called if Selection::hasForces() returns false.
634 const rvec& f() const
636 GMX_ASSERT(sel_->rawPositions_.f != nullptr, "Velocities accessed, but unavailable");
637 return sel_->rawPositions_.f[i_];
640 * Returns total mass for this position.
642 * Returns the total mass of atoms that make up this position.
643 * If there are no atoms associated or masses are not available,
646 real mass() const { return sel_->posMass_[i_]; }
648 * Returns total charge for this position.
650 * Returns the sum of charges of atoms that make up this position.
651 * If there are no atoms associated or charges are not available,
654 real charge() const { return sel_->posCharge_[i_]; }
655 //! Returns the number of atoms that make up this position.
656 int atomCount() const
658 return sel_->rawPositions_.m.mapb.index[i_ + 1] - sel_->rawPositions_.m.mapb.index[i_];
660 //! Return atom indices that make up this position.
661 ArrayRef<const int> atomIndices() const
663 const int* atoms = sel_->rawPositions_.m.mapb.a;
664 if (atoms == nullptr)
666 return ArrayRef<const int>();
668 const int first = sel_->rawPositions_.m.mapb.index[i_];
669 return constArrayRefFromArray(&atoms[first], atomCount());
672 * Returns whether this position is selected in the current frame.
674 * The return value is equivalent to \c refid() == -1. Returns always
675 * true if SelectionOption::dynamicMask() has not been set.
679 bool selected() const { return refId() >= 0; }
681 * Returns reference ID for this position.
683 * For dynamic selections, this provides means to associate positions
684 * across frames. After compilation, these IDs are consequently
685 * numbered starting from zero. For each frame, the ID then reflects
686 * the location of the position in the original array of positions.
687 * If SelectionOption::dynamicMask() has been set for the parent
688 * selection, the IDs for positions not present in the current
689 * selection are set to -1, otherwise they are removed completely.
692 * If a dynamic selection consists of at most three positions, after
693 * compilation refId() will return 0, 1, 2 for them, respectively.
694 * If for a particular frame, only the first and the third are present,
695 * refId() will return 0, 2.
696 * If SelectionOption::dynamicMask() has been set, all three positions
697 * can be accessed also for that frame and refId() will return 0, -1,
700 int refId() const { return sel_->rawPositions_.m.refid[i_]; }
702 * Returns mapped ID for this position.
704 * Returns ID of the position that corresponds to that set with
705 * Selection::setOriginalId().
707 * If for an array \c id, \c setOriginalId(i, id[i]) has been called
708 * for each \c i, then it always holds that
709 * \c mappedId()==id[refId()].
711 * Selection::setOriginalId() has not been called, the default values
712 * are dependent on type():
713 * - ::INDEX_ATOM: atom indices
714 * - ::INDEX_RES: residue indices
715 * - ::INDEX_MOL: molecule indices
717 * All the default values are zero-based.
719 int mappedId() const { return sel_->rawPositions_.m.mapid[i_]; }
722 * Allows passing a selection position directly to neighborhood searching.
724 * When initialized this way, AnalysisNeighborhoodPair objects return
725 * the index that can be used to access this position using
726 * Selection::position().
728 * Works exactly like if AnalysisNeighborhoodPositions had a
729 * constructor taking a SelectionPosition object as a parameter.
730 * See AnalysisNeighborhoodPositions for rationale and additional
733 operator AnalysisNeighborhoodPositions() const;
736 const internal::SelectionData* sel_;
741 inline SelectionPosition Selection::position(int i) const
743 return SelectionPosition(data(), i);