/[escript]/branches/schroedinger/escript/src/DataLazy.h
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Revision 1899 - (show annotations)
Mon Oct 20 05:13:24 2008 UTC (10 years, 6 months ago) by jfenwick
File MIME type: text/plain
File size: 6667 byte(s)
Branch commit.
Added some doco to DataLazy.
Made Data::integrate aware of DataLazy.


1
2 /*******************************************************
3 *
4 * Copyright (c) 2003-2008 by University of Queensland
5 * Earth Systems Science Computational Center (ESSCC)
6 * http://www.uq.edu.au/esscc
7 *
8 * Primary Business: Queensland, Australia
9 * Licensed under the Open Software License version 3.0
10 * http://www.opensource.org/licenses/osl-3.0.php
11 *
12 *******************************************************/
13
14
15 #if !defined escript_DataLazy_20081008_H
16 #define escript_DataLazy_20081008_H
17 #include "system_dep.h"
18
19 #include "DataAbstract.h"
20
21 #include <string>
22 #include <functional>
23
24 #include "LocalOps.h" // for tensor_binary_op
25
26 namespace escript {
27
28 enum ES_optype
29 {
30 UNKNOWNOP=0,
31 IDENTITY=1,
32 ADD=2,
33 SUB=3,
34 MUL=4,
35 DIV=5,
36 SIN=6,
37 COS=7,
38 TAN=8,
39 ASIN=9,
40 ACOS=10,
41 ATAN=11,
42 SINH=12,
43 COSH=13,
44 TANH=14,
45 ERF=15,
46 ASINH=16,
47 ACOSH=17,
48 ATANH=18,
49 LOG10=19,
50 LOG=20,
51 SIGN=21,
52 ABS=22,
53 NEG=23,
54 POS=24,
55 EXP=25,
56 SQRT=26,
57 RECIP=27,
58 GZ=28,
59 LZ=29,
60 GEZ=30,
61 LEZ=31
62 };
63
64 const std::string&
65 opToString(ES_optype op);
66
67 /**
68 \class escript::DataLazy
69 \brief Wraps an expression tree of other DataObjects.
70 The values of DataPoints are computed when requested rather than all at once.
71
72 NOTE: This class assumes that the Data being pointed at are immutable.
73 */
74
75 class DataLazy;
76
77 typedef POINTER_WRAPPER_CLASS(DataLazy) DataLazy_ptr;
78 typedef POINTER_WRAPPER_CLASS(const DataLazy) const_DataLazy_ptr;
79
80 class DataLazy : public DataAbstract
81 {
82
83 typedef DataAbstract parent;
84 typedef DataTypes::ValueType ValueType;
85 typedef DataTypes::ShapeType ShapeType;
86
87 public:
88 /**
89 \brief Create an IDENTITY DataLazy for the given DataAbstract.
90 \param p DataAbstract to be wrapped.
91 \throws DataException if p is lazy data or it is not constant, tagged or expanded.
92 */
93 ESCRIPT_DLL_API
94 DataLazy(DataAbstract_ptr p);
95
96
97 /**
98 \brief Produce a DataLazy for a unary operation.
99 \param left DataAbstract to be operated on.
100 \param op unary operation to perform.
101 \throws DataException if op is not a unary operation or if p cannot be converted to a DataLazy.
102 Note that IDENTITY is not considered a unary operation.
103 */
104 ESCRIPT_DLL_API
105 DataLazy(DataAbstract_ptr left, ES_optype op);
106
107 /**
108 \brief Produce a DataLazy for a binary operation.
109 \param left left operand
110 \param right right operand
111 \param op unary operation to perform.
112 \throws DataException if op is not a binary operation or if left or right cannot be converted to a DataLazy.
113 */
114 ESCRIPT_DLL_API
115 DataLazy(DataAbstract_ptr left, DataAbstract_ptr right, ES_optype op);
116
117 ESCRIPT_DLL_API
118 ~DataLazy();
119
120 /**
121 \brief Evaluate the lazy expression.
122 \return A DataReady with the value of the lazy expresion.
123 */
124 ESCRIPT_DLL_API
125 DataReady_ptr
126 resolve();
127
128 ESCRIPT_DLL_API
129 std::string
130 toString() const;
131
132 ESCRIPT_DLL_API
133 DataAbstract*
134 deepCopy();
135
136
137 /**
138 \brief
139 Return the number of doubles that would be stored for this Data object if it were resolved.
140 */
141 ESCRIPT_DLL_API
142 ValueType::size_type
143 getLength() const;
144
145
146 ESCRIPT_DLL_API
147 DataAbstract*
148 getSlice(const DataTypes::RegionType& region) const;
149
150
151 DataTypes::ValueType::size_type
152 getPointOffset(int sampleNo,
153 int dataPointNo) const;
154
155
156 /**
157 \return the number of samples which need to be stored to evaluate the expression.
158 */
159 ESCRIPT_DLL_API
160 int
161 getBuffsRequired() const;
162
163
164
165 private:
166 DataReady_ptr m_id; // For IDENTITY nodes, stores a wrapped value.
167 DataLazy_ptr m_left, m_right; // operands for operation.
168 ES_optype m_op; // operation to perform.
169 size_t m_length; // number of values represented by the operation
170
171 int m_buffsRequired; // how many samples are required to evaluate this expression
172 size_t m_samplesize; // number of values required to store a sample
173
174 char m_readytype; // E for expanded, T for tagged, C for constant
175
176
177 /**
178 Does the work for toString.
179 */
180 void
181 intoString(std::ostringstream& oss) const;
182
183 /**
184 \brief Converts the DataLazy into an IDENTITY storing the value of the expression.
185 This method uses the original methods on the Data class to evaluate the expressions.
186 For this reason, it should not be used on DataExpanded instances. (To do so would defeat
187 the purpose of using DataLazy in the first place).
188 */
189 void
190 collapse(); // converts the node into an IDENTITY node
191
192
193 /**
194 \brief Evaluates the expression using methods on Data.
195 This does the work for the collapse method.
196 For reasons of efficiency do not call this method on DataExpanded nodes.
197 */
198 DataReady_ptr
199 collapseToReady();
200
201 /**
202 \brief Compute the value of the expression for the given sample.
203 \return Vector which stores the value of the subexpression for the given sample.
204 \param v A vector to store intermediate results.
205 \param offset Index in v to begin storing results.
206 \param sampleNo Sample number to evaluate.
207 \param roffset (output parameter) the offset in the return vector where the result begins.
208
209 The return value will be an existing vector so do not deallocate it.
210 */
211 const ValueType*
212 resolveSample(ValueType& v, size_t offset ,int sampleNo, size_t& roffset);
213
214 /**
215 \brief Compute the value of the expression (binary operation) for the given sample.
216 \return Vector which stores the value of the subexpression for the given sample.
217 \param v A vector to store intermediate results.
218 \param offset Index in v to begin storing results.
219 \param sampleNo Sample number to evaluate.
220 \param roffset (output parameter) the offset in the return vector where the result begins.
221
222 The return value will be an existing vector so do not deallocate it.
223 If the result is stored in v it should be stored at the offset given.
224 Everything from offset to the end of v should be considered available for this method to use.
225 */
226 ValueType*
227 resolveUnary(ValueType& v, size_t offset,int sampleNo, size_t& roffset) const;
228
229 /**
230 \brief Compute the value of the expression (binary operation) for the given sample.
231 \return Vector which stores the value of the subexpression for the given sample.
232 \param v A vector to store intermediate results.
233 \param offset Index in v to begin storing results.
234 \param sampleNo Sample number to evaluate.
235 \param roffset (output parameter) the offset in the return vector where the result begins.
236
237 The return value will be an existing vector so do not deallocate it.
238 If the result is stored in v it should be stored at the offset given.
239 Everything from offset to the end of v should be considered available for this method to use.
240 */
241 ValueType*
242 resolveBinary(ValueType& v, size_t offset,int sampleNo, size_t& roffset) const;
243
244 };
245
246 }
247 #endif

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