/[escript]/branches/schroedinger/escript/src/DataLazy.h
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Contents of /branches/schroedinger/escript/src/DataLazy.h

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Revision 1901 - (show annotations)
Wed Oct 22 02:44:34 2008 UTC (10 years, 6 months ago) by jfenwick
File MIME type: text/plain
File size: 6854 byte(s)
Improved the api_doxygen target a bit.
Added some documentation.
Added FORCERESOLVE macro to a number of operations.

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 \brief Produces an IDENTITY DataLazy containing zero.
165 The result will have the same shape and functionspace as before.
166 */
167 ESCRIPT_DLL_API
168 virtual void
169 setToZero();
170
171 private:
172 DataReady_ptr m_id; // For IDENTITY nodes, stores a wrapped value.
173 DataLazy_ptr m_left, m_right; // operands for operation.
174 ES_optype m_op; // operation to perform.
175 size_t m_length; // number of values represented by the operation
176
177 int m_buffsRequired; // how many samples are required to evaluate this expression
178 size_t m_samplesize; // number of values required to store a sample
179
180 char m_readytype; // E for expanded, T for tagged, C for constant
181
182
183 /**
184 Does the work for toString.
185 */
186 void
187 intoString(std::ostringstream& oss) const;
188
189 /**
190 \brief Converts the DataLazy into an IDENTITY storing the value of the expression.
191 This method uses the original methods on the Data class to evaluate the expressions.
192 For this reason, it should not be used on DataExpanded instances. (To do so would defeat
193 the purpose of using DataLazy in the first place).
194 */
195 void
196 collapse(); // converts the node into an IDENTITY node
197
198
199 /**
200 \brief Evaluates the expression using methods on Data.
201 This does the work for the collapse method.
202 For reasons of efficiency do not call this method on DataExpanded nodes.
203 */
204 DataReady_ptr
205 collapseToReady();
206
207 /**
208 \brief Compute the value of the expression for the given sample.
209 \return Vector which stores the value of the subexpression for the given sample.
210 \param v A vector to store intermediate results.
211 \param offset Index in v to begin storing results.
212 \param sampleNo Sample number to evaluate.
213 \param roffset (output parameter) the offset in the return vector where the result begins.
214
215 The return value will be an existing vector so do not deallocate it.
216 */
217 const ValueType*
218 resolveSample(ValueType& v, size_t offset ,int sampleNo, size_t& roffset);
219
220 /**
221 \brief Compute the value of the expression (binary operation) for the given sample.
222 \return Vector which stores the value of the subexpression for the given sample.
223 \param v A vector to store intermediate results.
224 \param offset Index in v to begin storing results.
225 \param sampleNo Sample number to evaluate.
226 \param roffset (output parameter) the offset in the return vector where the result begins.
227
228 The return value will be an existing vector so do not deallocate it.
229 If the result is stored in v it should be stored at the offset given.
230 Everything from offset to the end of v should be considered available for this method to use.
231 */
232 ValueType*
233 resolveUnary(ValueType& v, size_t offset,int sampleNo, size_t& roffset) const;
234
235 /**
236 \brief Compute the value of the expression (binary operation) for the given sample.
237 \return Vector which stores the value of the subexpression for the given sample.
238 \param v A vector to store intermediate results.
239 \param offset Index in v to begin storing results.
240 \param sampleNo Sample number to evaluate.
241 \param roffset (output parameter) the offset in the return vector where the result begins.
242
243 The return value will be an existing vector so do not deallocate it.
244 If the result is stored in v it should be stored at the offset given.
245 Everything from offset to the end of v should be considered available for this method to use.
246 */
247 ValueType*
248 resolveBinary(ValueType& v, size_t offset,int sampleNo, size_t& roffset) const;
249
250 };
251
252 }
253 #endif

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