/[escript]/trunk/escript/src/DataLazy.h
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branches/schroedinger/escript/src/DataLazy.h revision 1865 by jfenwick, Thu Oct 9 03:53:57 2008 UTC branches/schroedinger_upto1946/escript/src/DataLazy.h revision 1992 by phornby, Fri Nov 7 04:51:04 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    // For the purposes of unit testing and maintaining sanity, it is important that this enum be contiguous
29  enum ES_optype  enum ES_optype
30  {  {
31      UNKNOWNOP=0,      UNKNOWNOP=0,
32      IDENTITY=1      IDENTITY=1,
33        ADD=2,
34        SUB=3,
35        MUL=4,
36        DIV=5,
37        POW=6,
38        SIN=POW+1,
39        COS=SIN+1,
40        TAN=SIN+2,
41        ASIN=SIN+3,
42        ACOS=SIN+4,
43        ATAN=SIN+5,
44        SINH=SIN+6,
45        COSH=SIN+7,
46        TANH=SIN+8,
47        ERF=SIN+9,
48        ASINH=SIN+10,
49        ACOSH=SIN+11,
50        ATANH=SIN+12,
51        LOG10=ATANH+1,
52        LOG=LOG10+1,
53        SIGN=LOG10+2,
54        ABS=LOG10+3,
55        NEG=LOG10+4,
56        POS=LOG10+5,
57        EXP=LOG10+6,
58        SQRT=LOG10+7,
59        RECIP=LOG10+8,
60        GZ=RECIP+1,
61        LZ=GZ+1,
62        GEZ=GZ+2,
63        LEZ=GZ+3
64  };  };
65    
66    ESCRIPT_DLL_API
67  const std::string&  const std::string&
68  opToString(ES_optype op);  opToString(ES_optype op);
69    
70  /**  /**
71  \class escript::DataLazy  \class escript::DataLazy
72  \brief Wraps an expression tree of other DataObjects.  \brief Wraps an expression tree of other DataObjects.
73  The values of DataPoints are computed when requested rather than all at once.  The data will be evaluated when required.
74    
75    
76    NOTE: This class assumes that the Data being pointed at are immutable.
77  */  */
78    
79    class DataLazy;
80    
81    typedef POINTER_WRAPPER_CLASS(DataLazy) DataLazy_ptr;
82    typedef POINTER_WRAPPER_CLASS(const DataLazy) const_DataLazy_ptr;
83    
84  class DataLazy : public DataAbstract  class DataLazy : public DataAbstract
85  {  {
86    
# Line 47  typedef DataTypes::ValueType ValueType; Line 89  typedef DataTypes::ValueType ValueType;
89  typedef DataTypes::ShapeType ShapeType;  typedef DataTypes::ShapeType ShapeType;
90    
91  public:  public:
92      /**
93      \brief Create an IDENTITY DataLazy for the given DataAbstract.
94      \param p DataAbstract to be wrapped.
95      \throws DataException if p is lazy data or it is not constant, tagged or expanded.
96      */
97    ESCRIPT_DLL_API    ESCRIPT_DLL_API
98    DataLazy(DataAbstract_ptr p);    DataLazy(DataAbstract_ptr p);
99    
100    
101      /**
102      \brief Produce a DataLazy for a unary operation.
103      \param left DataAbstract to be operated on.
104      \param op unary operation to perform.
105      \throws DataException if op is not a unary operation or if p cannot be converted to a DataLazy.
106      Note that IDENTITY is not considered a unary operation.
107      */
108      ESCRIPT_DLL_API
109      DataLazy(DataAbstract_ptr left, ES_optype op);
110    
111      /**
112      \brief Produce a DataLazy for a binary operation.
113      \param left left operand
114      \param right right operand
115      \param op unary operation to perform.
116      \throws DataException if op is not a binary operation or if left or right cannot be converted to a DataLazy.
117      */
118    ESCRIPT_DLL_API    ESCRIPT_DLL_API
119    DataLazy(DataAbstract_ptr left, DataAbstract_ptr right, ES_optype op);    DataLazy(DataAbstract_ptr left, DataAbstract_ptr right, ES_optype op);
120    
121    ESCRIPT_DLL_API    ESCRIPT_DLL_API
122    ~DataLazy();    ~DataLazy();
123    
   
   
124    /**    /**
125    \brief Compute all data points in the expression tree    \brief Evaluate the lazy expression.
126      \return A DataReady with the value of the lazy expresion.
127    */    */
128    ESCRIPT_DLL_API    ESCRIPT_DLL_API
129    DataReady_ptr resolve();    DataReady_ptr
130      resolve();
131    
132    ESCRIPT_DLL_API    ESCRIPT_DLL_API
133    std::string    std::string
# Line 91  public: Line 156  public:
156    getPointOffset(int sampleNo,    getPointOffset(int sampleNo,
157                   int dataPointNo) const;                   int dataPointNo) const;
158    
159      DataTypes::ValueType::size_type
160      getPointOffset(int sampleNo,
161                     int dataPointNo);
162    
163    
164      /**
165        \return the number of samples which need to be stored to evaluate the expression.
166      */
167      ESCRIPT_DLL_API
168      int
169      getBuffsRequired() const;
170    
171      /**
172         \brief Produces an IDENTITY DataLazy containing zero.
173         The result will have the same shape and functionspace as before.
174      */
175      ESCRIPT_DLL_API
176      virtual void
177      setToZero();
178    
179  private:  private:
180    DataAbstract_ptr m_left, m_right;    DataReady_ptr m_id;   //  For IDENTITY nodes, stores a wrapped value.
181    ES_optype m_op;    DataLazy_ptr m_left, m_right; // operands for operation.
182    size_t length;    // number of values represented by the operation    ES_optype m_op;   // operation to perform.
183      size_t m_length;  // number of values represented by the operation
184    
185      int m_buffsRequired;  // how many samples are required to evaluate this expression
186      size_t m_samplesize;  // number of values required to store a sample
187    
188      char m_readytype; // E for expanded, T for tagged, C for constant
189    
190    
191      /**
192      Does the work for toString.
193      */
194      void
195      intoString(std::ostringstream& oss) const;
196    
197      /**
198       \brief Converts the DataLazy into an IDENTITY storing the value of the expression.
199       This method uses the original methods on the Data class to evaluate the expressions.
200       For this reason, it should not be used on DataExpanded instances. (To do so would defeat
201       the purpose of using DataLazy in the first place).
202      */
203      void
204      collapse();       // converts the node into an IDENTITY node
205    
206    
207      /**
208      \brief Evaluates the expression using methods on Data.
209      This does the work for the collapse method.
210      For reasons of efficiency do not call this method on DataExpanded nodes.
211      */
212      DataReady_ptr
213      collapseToReady();
214    
215      /**
216      \brief Compute the value of the expression for the given sample.
217      \return Vector which stores the value of the subexpression for the given sample.
218      \param v A vector to store intermediate results.
219      \param offset Index in v to begin storing results.
220      \param sampleNo Sample number to evaluate.
221      \param roffset (output parameter) the offset in the return vector where the result begins.
222    
223      The return value will be an existing vector so do not deallocate it.
224      */
225      const ValueType*
226      resolveSample(ValueType& v,  size_t offset ,int sampleNo, size_t& roffset);
227    
228      /**
229      \brief Compute the value of the expression (binary operation) for the given sample.
230      \return Vector which stores the value of the subexpression for the given sample.
231      \param v A vector to store intermediate results.
232      \param offset Index in v to begin storing results.
233      \param sampleNo Sample number to evaluate.
234      \param roffset (output parameter) the offset in the return vector where the result begins.
235    
236      The return value will be an existing vector so do not deallocate it.
237      If the result is stored in v it should be stored at the offset given.
238      Everything from offset to the end of v should be considered available for this method to use.
239      */
240      ValueType*
241      resolveUnary(ValueType& v,  size_t offset,int sampleNo,  size_t& roffset) const;
242    
243      /**
244      \brief Compute the value of the expression (binary operation) for the given sample.
245      \return Vector which stores the value of the subexpression for the given sample.
246      \param v A vector to store intermediate results.
247      \param offset Index in v to begin storing results.
248      \param sampleNo Sample number to evaluate.
249      \param roffset (output parameter) the offset in the return vector where the result begins.
250    
251      The return value will be an existing vector so do not deallocate it.
252      If the result is stored in v it should be stored at the offset given.
253      Everything from offset to the end of v should be considered available for this method to use.
254      */
255      ValueType*
256      resolveBinary(ValueType& v,  size_t offset,int sampleNo,  size_t& roffset) const;
257    
258  };  };
259    
260  }  }

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