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36 * \brief API for neighborhood searching for analysis.
38 * The main part of the API is the class gmx::AnalysisNeighborhood.
39 * See the class documentation for usage.
41 * The classes within this file can be used independently of the other parts
43 * The library also uses the classes internally.
45 * \author Teemu Murtola <teemu.murtola@gmail.com>
47 * \ingroup module_selection
49 #ifndef GMX_SELECTION_NBSEARCH_H
50 #define GMX_SELECTION_NBSEARCH_H
52 #include <boost/shared_ptr.hpp>
54 #include "../legacyheaders/typedefs.h"
55 #include "../utility/common.h"
56 #include "../utility/gmxassert.h"
58 #include "indexutil.h"
67 class AnalysisNeighborhoodSearchImpl;
68 class AnalysisNeighborhoodPairSearchImpl;
71 class AnalysisNeighborhoodSearch;
72 class AnalysisNeighborhoodPairSearch;
75 * Neighborhood searching for analysis tools.
77 * This class implements neighborhood searching routines for analysis tools.
78 * The emphasis is in flexibility and ease of use; one main driver is to have
79 * a common implementation of grid-based searching to avoid replicating this in
80 * multiple tools (and to make more tools take advantage of the significant
81 * performance improvement this allows).
83 * To use the search, create an object of this type, call setCutoff() to
84 * initialize it, and then repeatedly call initSearch() to start a search with
85 * different sets of reference positions. For each set of reference positions,
86 * use methods in the returned AnalysisNeighborhoodSearch to find the reference
87 * positions that are within the given cutoff from a provided position.
89 * initSearch() is thread-safe and can be called from multiple threads. Each
90 * call returns a different instance of the search object that can be used
91 * independently of the others. The returned AnalysisNeighborhoodSearch
92 * objects are also thread-safe, and can be used concurrently from multiple
93 * threads. It is also possible to create multiple concurrent searches within
97 * Support for exclusions.
98 * The 4.5/4.6 C API had very low-level support for exclusions, which was not
99 * very convenient to use, and hadn't been tested much. The internal code that
100 * it used to do the exclusion during the search itself is still there, but it
101 * needs more thought on what would be a convenient way to initialize it.
102 * Can be implemented once there is need for it in some calling code.
105 * \ingroup module_selection
107 class AnalysisNeighborhood
110 //! Searching algorithm to use.
113 //! Select algorithm based on heuristic efficiency considerations.
114 eSearchMode_Automatic,
115 //! Use a simple loop over all pairs.
117 //! Use grid-based searching whenever possible.
121 //! Creates an uninitialized neighborhood search.
122 AnalysisNeighborhood();
123 ~AnalysisNeighborhood();
126 * Set cutoff distance for the neighborhood searching.
128 * \param[in] cutoff Cutoff distance for the search
129 * (<=0 stands for no cutoff).
131 * Currently, can only be called before the first call to initSearch().
132 * If this method is not called, no cutoff is used in the searches.
136 void setCutoff(real cutoff);
138 * Sets the algorithm to use for searching.
140 * \param[in] mode Search mode to use.
142 * Note that if \p mode is \ref eSearchMode_Grid, it is still only a
143 * suggestion: grid-based searching may not be possible with the
144 * provided input, in which case a simple search is still used.
145 * This is mainly useful for testing purposes to force a mode.
149 void setMode(SearchMode mode);
150 //! Returns the currently active search mode.
151 SearchMode mode() const;
154 * Initializes neighborhood search for a set of positions.
156 * \param[in] pbc PBC information for the frame.
157 * \param[in] n Number of reference positions for the frame.
158 * \param[in] x \p n reference positions for the frame.
159 * \returns Search object that can be used to find positions from
160 * \p x within the given cutoff.
161 * \throws std::bad_alloc if out of memory.
163 AnalysisNeighborhoodSearch
164 initSearch(const t_pbc *pbc, int n, const rvec x[]);
166 * Initializes neighborhood search for a set of positions.
168 * \param[in] pbc PBC information for the frame.
169 * \param[in] p Reference positions for the frame.
170 * \returns Search object that can be used to find positions from
171 * \p p within the given cutoff.
172 * \throws std::bad_alloc if out of memory.
174 AnalysisNeighborhoodSearch
175 initSearch(const t_pbc *pbc, const gmx_ana_pos_t *p);
180 PrivateImplPointer<Impl> impl_;
184 * Value type to represent a pair of positions found in neighborhood searching.
186 * Methods in this class do not throw.
189 * \ingroup module_selection
191 class AnalysisNeighborhoodPair
194 //! Initializes an invalid pair.
195 AnalysisNeighborhoodPair() : refIndex_(-1), testIndex_(0) {}
196 //! Initializes a pair object with the given data.
197 AnalysisNeighborhoodPair(int refIndex, int testIndex)
198 : refIndex_(refIndex), testIndex_(testIndex)
203 * Whether this pair is valid.
205 * If isValid() returns false, other methods should not be called.
207 bool isValid() const { return refIndex_ >= 0; }
210 * Returns the index of the reference position in the pair.
212 * This index is always the index into the position array provided to
213 * AnalysisNeighborhood::initSearch().
217 GMX_ASSERT(isValid(), "Accessing invalid object");
221 * Returns the index of the test position in the pair.
223 * The contents of this index depends on the context (method call) that
225 * If there was no array in the call, this index is zero.
227 int testIndex() const
229 GMX_ASSERT(isValid(), "Accessing invalid object");
239 * Initialized neighborhood search with a fixed set of reference positions.
241 * An instance of this class is obtained through
242 * AnalysisNeighborhood::initSearch(), and can be used to do multiple searches
243 * against the provided set of reference positions.
244 * It is possible to create concurrent pair searches (including from different
245 * threads), as well as call other methods in this class while a pair search is
248 * This class works like a pointer: copies of it point to the same search.
249 * In general, avoid creating copies, and only use the copy/assignment support
250 * for moving the variable around. With C++11, this class would best be
253 * Methods in this class do not throw unless otherwise indicated.
256 * Make it such that reset() is not necessary to call in code that repeatedly
257 * assigns the result of AnalysisNeighborhood::initSearch() to the same
258 * variable (see sm_distance.cpp).
261 * Consider merging nearestPoint() and minimumDistance() by adding the distance
262 * to AnalysisNeighborhoodPair.
265 * \ingroup module_selection
267 class AnalysisNeighborhoodSearch
271 * Internal short-hand type for a pointer to the implementation class.
273 * shared_ptr is used here to automatically keep a reference count to
274 * track whether an implementation class is still used outside the
275 * AnalysisNeighborhood object. Ownership currently always stays with
276 * AnalysisNeighborhood; it always keeps one instance of the pointer.
278 typedef boost::shared_ptr<internal::AnalysisNeighborhoodSearchImpl>
282 * Initializes an invalid search.
284 * Such an object cannot be used for searching. It needs to be
285 * assigned a value from AnalysisNeighborhood::initSearch() before it
286 * can be used. Provided to allow declaring a variable to hold the
287 * search before calling AnalysisNeighborhood::initSearch().
289 AnalysisNeighborhoodSearch();
291 * Internally initialize the search.
293 * Used to implement AnalysisNeighborhood::initSearch().
294 * Cannot be called from user code.
296 explicit AnalysisNeighborhoodSearch(const ImplPointer &impl);
299 * Clears this search.
301 * Equivalent to \c "*this = AnalysisNeighborhoodSearch();".
302 * Currently, this is necessary to avoid unnecessary memory allocation
303 * if the previous search variable is still in scope when you want to
304 * call AnalysisNeighborhood::initSearch() again.
309 * Returns the searching algorithm that this search is using.
311 * The return value is never AnalysisNeighborhood::eSearchMode_Automatic.
313 AnalysisNeighborhood::SearchMode mode() const;
316 * Check whether a point is within a neighborhood.
318 * \param[in] x Test position.
319 * \returns true if the test position is within the cutoff of any
320 * reference position.
322 bool isWithin(const rvec x) const;
324 * Check whether a point is within a neighborhood.
326 * \param[in] p Test positions.
327 * \param[in] i Use the i'th position in \p p for testing.
328 * \returns true if the test position is within the cutoff of any
329 * reference position.
331 bool isWithin(const gmx_ana_pos_t *p, int i) const;
333 * Calculates the minimum distance from the reference points.
335 * \param[in] x Test position.
336 * \returns The distance to the nearest reference position, or the
337 * cutoff value if there are no reference positions within the
340 real minimumDistance(const rvec x) const;
342 * Calculates the minimum distance from the reference points.
344 * \param[in] p Test positions.
345 * \param[in] i Use the i'th position in \p p for testing.
346 * \returns The distance to the nearest reference position, or the
347 * cutoff value if there are no reference positions within the
350 real minimumDistance(const gmx_ana_pos_t *p, int i) const;
352 * Finds the closest reference point.
354 * \param[in] x Test position.
355 * \returns The reference index identifies the reference position
356 * that is closest to the test position.
357 * The test index is always zero. The returned pair is invalid if
358 * no reference position is within the cutoff.
360 AnalysisNeighborhoodPair nearestPoint(const rvec x) const;
362 * Finds the closest reference point.
364 * \param[in] p Test positions.
365 * \param[in] i Use the i'th position in \p p for testing.
366 * \returns The reference index identifies the reference position
367 * that is closest to the test position.
368 * The test index is always \p i. The returned pair is invalid if
369 * no reference position is within the cutoff.
371 AnalysisNeighborhoodPair nearestPoint(const gmx_ana_pos_t *p, int i) const;
374 * Start a search to find reference positions within a cutoff.
376 * \param[in] x Test position to search the neighbors for.
377 * \returns Initialized search object to loop through all reference
378 * positions within the configured cutoff.
379 * \throws std::bad_alloc if out of memory.
381 * In the AnalysisNeighborhoodPair objects returned by the search, the
382 * test index is always zero.
384 AnalysisNeighborhoodPairSearch startPairSearch(const rvec x);
386 * Start a search to find reference positions within a cutoff.
388 * \param[in] p Test positions.
389 * \param[in] i Use the i'th position in \p p for testing.
390 * \returns Initialized search object to loop through all reference
391 * positions within the configured cutoff.
392 * \throws std::bad_alloc if out of memory.
394 * In the AnalysisNeighborhoodPair objects returned by the search, the
395 * test index is always \p i.
397 AnalysisNeighborhoodPairSearch startPairSearch(const gmx_ana_pos_t *p, int i);
400 typedef internal::AnalysisNeighborhoodSearchImpl Impl;
406 * Initialized neighborhood pair search with a fixed set of positions.
408 * This class is used to loop through pairs of neighbors within the cutoff
409 * provided to AnalysisNeighborhood. The following code demonstrates its use:
411 gmx::AnalysisNeighborhood nb;
412 nb.setCutoff(cutoff);
413 gmx::AnalysisNeighborhoodSearch search = nb.initSearch(pbc, nref, xref);
414 gmx::AnalysisNeighborhoodPairSearch pairSearch = search.startPairSearch(x);
415 gmx::AnalysisNeighborhoodPair pair;
416 while (pairSearch.findNextPair(&pair))
418 // <do something for each found pair the information in pair>
422 * It is not possible to use a single search object from multiple threads
425 * This class works like a pointer: copies of it point to the same search.
426 * In general, avoid creating copies, and only use the copy/assignment support
427 * for moving the variable around. With C++11, this class would best be
430 * Methods in this class do not throw.
433 * \ingroup module_selection
435 class AnalysisNeighborhoodPairSearch
439 * Internal short-hand type for a pointer to the implementation class.
441 * See AnalysisNeighborhoodSearch::ImplPointer for rationale of using
442 * shared_ptr and ownership semantics.
444 typedef boost::shared_ptr<internal::AnalysisNeighborhoodPairSearchImpl>
448 * Internally initialize the search.
450 * Used to implement AnalysisNeighborhoodSearch::startPairSearch().
451 * Cannot be called from user code.
453 explicit AnalysisNeighborhoodPairSearch(const ImplPointer &impl);
456 * Finds the next pair within the cutoff.
458 * \param[out] pair Information about the found pair.
459 * \returns false if there were no more pairs.
461 * If the method returns false, \p pair will be invalid.
463 * \see AnalysisNeighborhoodPair
464 * \see AnalysisNeighborhoodSearch::startPairSearch()
466 bool findNextPair(AnalysisNeighborhoodPair *pair);