| 1 | //
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| 2 | // C++ Interface: Locator
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| 3 | //
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| 4 | // Description:
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| 5 | //
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| 6 | //
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| 7 | // Author: Takeshi Nakazato <takeshi.nakazato@nao.ac.jp>, (C) 2012
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| 8 | //
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| 9 | // Copyright: See COPYING file that comes with this distribution
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| 10 | //
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| 11 | //
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| 12 | #ifndef ASAP_LOCATOR_H
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| 13 | #define ASAP_LOCATOR_H
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| 14 |
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| 15 | namespace asap {
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| 16 |
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| 17 | /**
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| 18 | * Base class for locate operation
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| 19 | * @author TakeshiNakazato
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| 20 | */
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| 21 | class Locator {
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| 22 | public:
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| 23 | // Default constructor.
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| 24 | Locator();
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| 25 |
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| 26 | // Construct with data.
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| 27 | // @param[in] v pointer to input data.
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| 28 | // @param[in] n length of the data.
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| 29 | // @param[in] copystorage whether allocate internal memory or not.
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| 30 | // @see set()
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| 31 | Locator(double *v, unsigned int n, bool copystorage=true);
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| 32 |
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| 33 | // Set data. The data must be sorted in either ascending or descending
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| 34 | // order, and must not have any duplicate elements.
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| 35 | // @param[in] v pointer to input data.
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| 36 | // @param[in] n length of the data.
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| 37 | // @param[in] copystorage whether allocate internal memory or not.
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| 38 | //
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| 39 | // Setting copystorage=false is bit faster since it directly points
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| 40 | // to the input array instead to allocate memory and copy input array.
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| 41 | // However, you have to be careful to set copystorage to false since
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| 42 | // it will take a risk to allow to edit the data to be searched from
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| 43 | // outside the class.
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| 44 | void set(double *v, unsigned int n, bool copystorage=true);
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| 45 |
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| 46 | // Destructor.
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| 47 | virtual ~Locator();
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| 48 |
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| 49 | // Return right hand side index of location.
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| 50 | // @param[in] x input value to be located.
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| 51 | // @return location as an index j.
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| 52 | //
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| 53 | // Returned index j satisfies x_[j-1] < x <= x_[j] for ascending
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| 54 | // case while x_[j-1] > x >= x_[j] for descending case.
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| 55 | // Returned value 0 or x.nelements() indicates out of range.
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| 56 | virtual unsigned int locate(double x) = 0;
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| 57 |
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| 58 | protected:
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| 59 | // Bisection search.
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| 60 | // @param[in] x input value to be located.
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| 61 | // @param[in] left the leftmost index to search.
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| 62 | // @param[in] right the rightmost index to search.
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| 63 | unsigned int bisection(double x, unsigned int left, unsigned int right);
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| 64 |
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| 65 | // Hunt algorithm
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| 66 | // @param[in] x input value to be located.
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| 67 | // @param[in,out] left input: the starting point for hunt.
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| 68 | // output: the left index of hunted region.
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| 69 | // @param[out] right the right index of hunted region.
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| 70 | void hunt(double x, unsigned int &left, unsigned int &right);
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| 71 |
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| 72 | // Pointer to the data.
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| 73 | double *x_;
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| 74 |
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| 75 | // Length of the data.
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| 76 | unsigned int n_;
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| 77 |
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| 78 | // Is data ascending or descending?
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| 79 | bool ascending_;
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| 80 |
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| 81 | // Is internal storage allocated?
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| 82 | bool copy_;
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| 83 | };
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| 84 |
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| 85 | }
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| 86 | #endif
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