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39 * This file contains datatypes and function declarations necessary
40 * for AWH to interface with the grid code.
42 * The grid organizes spatial properties of the AWH coordinate points.
43 * This includes traversing points in a specific order, locating
44 * neighboring points and calculating distances. Multiple dimensions
45 * as well as periodic dimensions are supported.
47 * \todo: Replace this by a more generic grid class once that is available.
49 * \author Viveca Lindahl
50 * \author Berk Hess <hess@kth.se>
54 #ifndef GMX_AWH_BIASGRID_H
55 #define GMX_AWH_BIASGRID_H
61 #include "dimparams.h" /* This is needed for awh_dvec */
69 * \brief An axis, i.e. dimension, of the grid.
74 /*! \brief Constructor.
76 * The spacing and number of points are set such that we have
77 * at least the requested point density.
78 * Requesting 0 point density results in the minimum number
81 * \param[in] origin Starting value.
82 * \param[in] end End value.
83 * \param[in] period Period, pass 0 if not periodic.
84 * \param[in] pointDensity Requested number of point per unit of axis length.
86 GridAxis(double origin, double end, double period, double pointDensity);
88 /*! \brief Constructor.
90 * \param[in] origin Starting value.
91 * \param[in] end End value.
92 * \param[in] period Period, pass 0 if not periodic.
93 * \param[in] numPoints The number of points.
94 * \param[in] isFepLambdaAxis If this axis is controlling lambda.
96 GridAxis(double origin, double end, double period, int numPoints, bool isFepLambdaAxis);
98 /*! \brief Returns whether the axis has periodic boundaries.
100 bool isPeriodic() const { return period_ > 0; }
102 /*! \brief Returns the period of the grid along the axis.
104 double period() const { return period_; }
106 /*! \brief Returns the grid origin along the axis.
108 double origin() const { return origin_; }
110 /*! \brief Returns the grid point spacing along the axis.
112 double spacing() const { return spacing_; }
114 /*! \brief Returns the number of grid points along the axis.
116 int numPoints() const { return numPoints_; }
118 /*! \brief Returns the period of the grid in points along the axis.
120 * Returns 0 if the axis is not periodic.
122 int numPointsInPeriod() const { return numPointsInPeriod_; }
124 /*! \brief Returns the length of the interval.
126 * This returns the distance obtained by connecting the origin point to
127 * the end point in the positive direction. Note that this is generally
128 * not the shortest distance. For period > 0, both origin and
129 * end are expected to take values in the same periodic interval.
131 double length() const { return length_; }
133 /*! \brief Map a value to the nearest point index along an axis.
135 * \param[in] value Value along the axis.
136 * \returns the index nearest to the value.
138 int nearestIndex(double value) const;
140 /*! \brief Returns whether this axis is coupled to the free energy lambda state.
142 bool isFepLambdaAxis() const { return isFepLambdaAxis_; }
145 double origin_; /**< Interval start value */
146 double length_; /**< Interval length */
147 double period_; /**< The period, 0 if not periodic */
148 double spacing_; /**< Point spacing */
149 int numPoints_; /**< Number of points in the interval */
150 int numPointsInPeriod_; /**< Number of points in a period (0 if no periodicity) */
151 bool isFepLambdaAxis_; /**< If this axis is coupled to the system's free energy lambda state */
155 * \brief A point in the grid.
157 * A grid point has a coordinate value and a coordinate index of the same dimensionality as the
158 * grid. It knows the linear indices of its neighboring point (which are useful only when handed up
163 awh_dvec coordValue; /**< Multidimensional coordinate value of this point */
164 awh_ivec index; /**< Multidimensional point indices */
165 std::vector<int> neighbor; /**< Linear point indices of the neighboring points */
169 * \brief The grid for a single bias, generally multidimensional and periodic.
171 * The grid discretizes a multidimensional space with some given resolution.
172 * Each dimension is represented by an axis which sets the spatial extent,
173 * point spacing and periodicity of the grid in that direction.
178 /*! \brief Initializes the grid points.
184 * The point density per sigma of the Gaussian distribution in an umbrella.
186 * This value should be at least 1 to uniformly cover the reaction coordinate
187 * range with density and having it larger than 1 does not add information.
189 static constexpr double c_numPointsPerSigma = 1.0;
191 //! Cut-off in sigma for considering points, neglects 4e-8 of the density.
192 static constexpr double c_scopeCutoff = 5.5;
194 /*! \brief Construct a grid using AWH input parameters.
196 * \param[in] dimParams Dimension parameters including the expected inverse variance of the
197 * coordinate living on the grid (determines the grid spacing).
198 * \param[in] awhDimParams Dimension params from inputrec.
200 BiasGrid(const std::vector<DimParams>& dimParams, const AwhDimParams* awhDimParams);
202 /*! \brief Returns the number of points in the grid.
204 * \returns the number of points in the grid.
206 size_t numPoints() const { return point_.size(); }
208 /*! \brief Returns a reference to a point on the grid.
210 * \returns a constant reference to a point on the grid.
212 const GridPoint& point(size_t pointIndex) const { return point_[pointIndex]; }
214 /*! \brief Returns the dimensionality of the grid.
216 * \returns the dimensionality of the grid.
218 int numDimensions() const { return axis_.size(); }
220 /*! \brief Returns the grid axes.
222 * \returns a constant reference to the grid axes.
224 const std::vector<GridAxis>& axis() const { return axis_; }
226 /*! \brief Returns a grid axis.
228 * param[in] dim Dimension to return the grid axis for.
229 * \returns a constant reference to the grid axis.
231 const GridAxis& axis(int dim) const { return axis_[dim]; }
233 /*! \brief Find the grid point with value nearest to the given value.
235 * \param[in] value Value vector.
236 * \returns the grid point index.
238 int nearestIndex(const awh_dvec value) const;
240 /*! \brief Query if the value is in the grid.
242 * \param[in] value Value vector.
243 * \returns true if the value is in the grid.
244 * \note It is assumed that any periodicity of value has already been taken care of.
246 bool covers(const awh_dvec value) const;
248 /*! \brief Returns true if the grid has a free energy lambda state axis at all.
250 bool hasLambdaAxis() const
252 return std::any_of(std::begin(axis_), std::end(axis_),
253 [](const auto& axis) { return axis.isFepLambdaAxis(); });
257 * Returns the index of a free energy lambda state axis (there can be
258 * no more than one) if there is one.
260 std::optional<int> lambdaAxisIndex() const;
263 * Returns the number of free energy lambda states in the grid (the number
264 * of points along a free energy lambda state axis) or 0 if there are no free energy
267 int numFepLambdaStates() const;
270 std::vector<GridPoint> point_; /**< Points on the grid */
271 std::vector<GridAxis> axis_; /**< Axes, one for each dimension. */
276 /*! \brief Convert a multidimensional grid point index to a linear one.
278 * \param[in] grid The grid.
279 * \param[in] indexMulti Multidimensional grid point index to convert to a linear one.
280 * \returns the linear index.
282 int multiDimGridIndexToLinear(const BiasGrid& grid, const awh_ivec indexMulti);
284 /*! \brief Convert multidimensional array index to a linear one.
286 * \param[in] indexMulti Multidimensional index to convert to a linear one.
287 * \param[in] numDim Number of dimensions of the array.
288 * \param[in] numPointsDim Number of points of the array.
289 * \returns the linear index.
290 * \note This function can be used without having an initialized grid.
292 int multiDimArrayIndexToLinear(const awh_ivec indexMulti, int numDim, const awh_ivec numPointsDim);
294 /*! \brief Convert a linear grid point index to a multidimensional one.
296 * \param[in] grid The grid.
297 * \param[in] indexLinear Linear grid point index to convert to a multidimensional one.
298 * \param[out] indexMulti The multidimensional index.
300 void linearGridindexToMultiDim(const BiasGrid& grid, int indexLinear, awh_ivec indexMulti);
302 /*! \brief Convert a linear array index to a multidimensional one.
304 * \param[in] indexLinear Linear array index
305 * \param[in] ndim Number of dimensions of the array.
306 * \param[in] numPointsDim Number of points for each dimension.
307 * \param[out] indexMulti The multidimensional index.
309 void linearArrayIndexToMultiDim(int indexLinear, int ndim, const awh_ivec numPointsDim, awh_ivec indexMulti);
312 * Find the next grid point in the sub-part of the grid given a starting point.
314 * The given grid point index is updated to the next valid grid point index
315 * by traversing the sub-part of the grid, here termed the subgrid.
316 * Since the subgrid range might extend beyond the actual size of the grid,
317 * the subgrid is traversed until a point both in the subgrid and grid is
318 * found. If no point is found, the function returns false and the index is
319 * not modified. The starting point needs to be inside of the subgrid. However,
320 * if this index is not given, meaning < 0, then the search is initialized at
321 * the subgrid origin, i.e. in this case the "next" grid point index is
322 * defined to be the first common grid/subgrid point.
324 * \param[in] grid The grid.
325 * \param[in] subgridOrigin Vector locating the subgrid origin relative to the grid origin.
326 * \param[in] subgridNpoints Number of points along each subgrid dimension.
327 * \param[in,out] gridPointIndex Pointer to the starting/next grid point index.
328 * \returns true if the grid point was updated.
330 bool advancePointInSubgrid(const BiasGrid& grid,
331 const awh_ivec subgridOrigin,
332 const awh_ivec subgridNpoints,
333 int* gridPointIndex);
335 /*! \brief Maps each point in the grid to a point in the data grid.
337 * This functions maps an AWH bias grid to a user provided input data grid.
338 * The value of data grid point i along dimension d is given by data[d][i].
339 * The number of dimensions of the data should equal that of the grid.
340 * A fatal error is thrown if extracting the data fails or the data does not cover the whole grid.
342 * \param[out] gridpointToDatapoint Array mapping each grid point to a data point index.
343 * \param[in] data 2D array in format ndim x ndatapoints with data grid point values.
344 * \param[in] numDataPoints Number of data points.
345 * \param[in] dataFilename The data filename.
346 * \param[in] grid The grid.
347 * \param[in] correctFormatMessage String to include in error message if extracting the data fails.
349 void mapGridToDataGrid(std::vector<int>* gridpointToDatapoint,
350 const double* const* data,
352 const std::string& dataFilename,
353 const BiasGrid& grid,
354 const std::string& correctFormatMessage);
357 * Get the deviation along one dimension from the given value to a point in the grid.
359 * \param[in] grid The grid.
360 * \param[in] dimIndex Dimensional index in [0, ndim -1].
361 * \param[in] pointIndex BiasGrid point index.
362 * \param[in] value Value along the given dimension.
363 * \returns the deviation of the given value to the given point.
365 double getDeviationFromPointAlongGridAxis(const BiasGrid& grid, int dimIndex, int pointIndex, double value);
368 * Get the deviation from one point to another along one dimension in the grid.
370 * \param[in] grid The grid.
371 * \param[in] dimIndex Dimensional index in [0, ndim -1].
372 * \param[in] pointIndex1 Grid point index of the first point.
373 * \param[in] pointIndex2 Grid point index of the second point.
374 * \returns the deviation of the two points along the given axis.
376 double getDeviationFromPointAlongGridAxis(const BiasGrid& grid, int dimIndex, int pointIndex1, int pointIndex2);
379 * Checks whether two points are along a free energy lambda state axis.
381 * \param[in] grid The grid.
382 * \param[in] pointIndex1 Grid point index of the first point.
383 * \param[in] pointIndex2 Grid point index of the second point.
384 * \returns true if the two points are along a free energy lambda state axis.
386 bool pointsAlongLambdaAxis(const BiasGrid& grid, int pointIndex1, int pointIndex2);
389 * Checks whether two points are different in the free energy lambda state
390 * dimension (if any).
392 * \param[in] grid The grid.
393 * \param[in] pointIndex1 Grid point index of the first point.
394 * \param[in] pointIndex2 Grid point index of the second point.
395 * \returns true if the two points have different lambda values.
397 bool pointsHaveDifferentLambda(const BiasGrid& grid, int pointIndex1, int pointIndex2);