/[escript]/trunk/escript/src/DataLazy.h
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revision 1865 by jfenwick, Thu Oct 9 03:53:57 2008 UTC revision 1910 by jfenwick, Thu Oct 23 03:05:28 2008 UTC
# Line 17  Line 17 
17  #include "system_dep.h"  #include "system_dep.h"
18    
19  #include "DataAbstract.h"  #include "DataAbstract.h"
 //#include "DataTypes.h"  
 //#include "FunctionSpace.h"  
20    
21  #include <string>  #include <string>
22    #include <functional>
23    
24    #include "LocalOps.h"       // for tensor_binary_op
25    
26  namespace escript {  namespace escript {
27    
28  enum ES_optype  enum ES_optype
29  {  {
30      UNKNOWNOP=0,      UNKNOWNOP=0,
31      IDENTITY=1      IDENTITY=1,
32        ADD=2,
33        SUB=3,
34        MUL=4,
35        DIV=5,
36        POW=6,
37        SIN=POW+1,
38        COS=SIN+1,
39        TAN=SIN+2,
40        ASIN=SIN+3,
41        ACOS=SIN+4,
42        ATAN=SIN+5,
43        SINH=SIN+6,
44        COSH=SIN+7,
45        TANH=SIN+8,
46        ERF=SIN+9,
47        ASINH=SIN+10,
48        ACOSH=SIN+11,
49        ATANH=SIN+12,
50        LOG10=ATANH+1,
51        LOG=LOG10+1,
52        SIGN=LOG10+2,
53        ABS=LOG10+3,
54        NEG=LOG10+4,
55        POS=LOG10+5,
56        EXP=LOG10+6,
57        SQRT=LOG10+7,
58        RECIP=LOG10+8,
59        GZ=RECIP+1,
60        LZ=GZ+1,
61        GEZ=GZ+2,
62        LEZ=GZ+3
63  };  };
64    
65  const std::string&  const std::string&
# Line 36  opToString(ES_optype op); Line 68  opToString(ES_optype op);
68  /**  /**
69  \class escript::DataLazy  \class escript::DataLazy
70  \brief Wraps an expression tree of other DataObjects.  \brief Wraps an expression tree of other DataObjects.
71  The values of DataPoints are computed when requested rather than all at once.  The data will be evaluated when required.
72    
73    
74    NOTE: This class assumes that the Data being pointed at are immutable.
75  */  */
76    
77    class DataLazy;
78    
79    typedef POINTER_WRAPPER_CLASS(DataLazy) DataLazy_ptr;
80    typedef POINTER_WRAPPER_CLASS(const DataLazy) const_DataLazy_ptr;
81    
82  class DataLazy : public DataAbstract  class DataLazy : public DataAbstract
83  {  {
84    
# Line 47  typedef DataTypes::ValueType ValueType; Line 87  typedef DataTypes::ValueType ValueType;
87  typedef DataTypes::ShapeType ShapeType;  typedef DataTypes::ShapeType ShapeType;
88    
89  public:  public:
90      /**
91      \brief Create an IDENTITY DataLazy for the given DataAbstract.
92      \param p DataAbstract to be wrapped.
93      \throws DataException if p is lazy data or it is not constant, tagged or expanded.
94      */
95    ESCRIPT_DLL_API    ESCRIPT_DLL_API
96    DataLazy(DataAbstract_ptr p);    DataLazy(DataAbstract_ptr p);
97    
98    
99      /**
100      \brief Produce a DataLazy for a unary operation.
101      \param left DataAbstract to be operated on.
102      \param op unary operation to perform.
103      \throws DataException if op is not a unary operation or if p cannot be converted to a DataLazy.
104      Note that IDENTITY is not considered a unary operation.
105      */
106      ESCRIPT_DLL_API
107      DataLazy(DataAbstract_ptr left, ES_optype op);
108    
109      /**
110      \brief Produce a DataLazy for a binary operation.
111      \param left left operand
112      \param right right operand
113      \param op unary operation to perform.
114      \throws DataException if op is not a binary operation or if left or right cannot be converted to a DataLazy.
115      */
116    ESCRIPT_DLL_API    ESCRIPT_DLL_API
117    DataLazy(DataAbstract_ptr left, DataAbstract_ptr right, ES_optype op);    DataLazy(DataAbstract_ptr left, DataAbstract_ptr right, ES_optype op);
118    
119    ESCRIPT_DLL_API    ESCRIPT_DLL_API
120    ~DataLazy();    ~DataLazy();
121    
   
   
122    /**    /**
123    \brief Compute all data points in the expression tree    \brief Evaluate the lazy expression.
124      \return A DataReady with the value of the lazy expresion.
125    */    */
126    ESCRIPT_DLL_API    ESCRIPT_DLL_API
127    DataReady_ptr resolve();    DataReady_ptr
128      resolve();
129    
130    ESCRIPT_DLL_API    ESCRIPT_DLL_API
131    std::string    std::string
# Line 91  public: Line 154  public:
154    getPointOffset(int sampleNo,    getPointOffset(int sampleNo,
155                   int dataPointNo) const;                   int dataPointNo) const;
156    
157    
158      /**
159        \return the number of samples which need to be stored to evaluate the expression.
160      */
161      ESCRIPT_DLL_API
162      int
163      getBuffsRequired() const;
164    
165      /**
166         \brief Produces an IDENTITY DataLazy containing zero.
167         The result will have the same shape and functionspace as before.
168      */
169      ESCRIPT_DLL_API
170      virtual void
171      setToZero();
172    
173  private:  private:
174    DataAbstract_ptr m_left, m_right;    DataReady_ptr m_id;   //  For IDENTITY nodes, stores a wrapped value.
175    ES_optype m_op;    DataLazy_ptr m_left, m_right; // operands for operation.
176    size_t length;    // number of values represented by the operation    ES_optype m_op;   // operation to perform.
177      size_t m_length;  // number of values represented by the operation
178    
179      int m_buffsRequired;  // how many samples are required to evaluate this expression
180      size_t m_samplesize;  // number of values required to store a sample
181    
182      char m_readytype; // E for expanded, T for tagged, C for constant
183    
184    
185      /**
186      Does the work for toString.
187      */
188      void
189      intoString(std::ostringstream& oss) const;
190    
191      /**
192       \brief Converts the DataLazy into an IDENTITY storing the value of the expression.
193       This method uses the original methods on the Data class to evaluate the expressions.
194       For this reason, it should not be used on DataExpanded instances. (To do so would defeat
195       the purpose of using DataLazy in the first place).
196      */
197      void
198      collapse();       // converts the node into an IDENTITY node
199    
200    
201      /**
202      \brief Evaluates the expression using methods on Data.
203      This does the work for the collapse method.
204      For reasons of efficiency do not call this method on DataExpanded nodes.
205      */
206      DataReady_ptr
207      collapseToReady();
208    
209      /**
210      \brief Compute the value of the expression for the given sample.
211      \return Vector which stores the value of the subexpression for the given sample.
212      \param v A vector to store intermediate results.
213      \param offset Index in v to begin storing results.
214      \param sampleNo Sample number to evaluate.
215      \param roffset (output parameter) the offset in the return vector where the result begins.
216    
217      The return value will be an existing vector so do not deallocate it.
218      */
219      const ValueType*
220      resolveSample(ValueType& v,  size_t offset ,int sampleNo, size_t& roffset);
221    
222      /**
223      \brief Compute the value of the expression (binary operation) for the given sample.
224      \return Vector which stores the value of the subexpression for the given sample.
225      \param v A vector to store intermediate results.
226      \param offset Index in v to begin storing results.
227      \param sampleNo Sample number to evaluate.
228      \param roffset (output parameter) the offset in the return vector where the result begins.
229    
230      The return value will be an existing vector so do not deallocate it.
231      If the result is stored in v it should be stored at the offset given.
232      Everything from offset to the end of v should be considered available for this method to use.
233      */
234      ValueType*
235      resolveUnary(ValueType& v,  size_t offset,int sampleNo,  size_t& roffset) const;
236    
237      /**
238      \brief Compute the value of the expression (binary operation) for the given sample.
239      \return Vector which stores the value of the subexpression for the given sample.
240      \param v A vector to store intermediate results.
241      \param offset Index in v to begin storing results.
242      \param sampleNo Sample number to evaluate.
243      \param roffset (output parameter) the offset in the return vector where the result begins.
244    
245      The return value will be an existing vector so do not deallocate it.
246      If the result is stored in v it should be stored at the offset given.
247      Everything from offset to the end of v should be considered available for this method to use.
248      */
249      ValueType*
250      resolveBinary(ValueType& v,  size_t offset,int sampleNo,  size_t& roffset) const;
251    
252  };  };
253    
254  }  }

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