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TiledCollapser.h
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1 //# TiledCollapser.h: Abstract base class to collapse chunks for LatticeApply
2 //# Copyright (C) 1996,1997,1998
3 //# Associated Universities, Inc. Washington DC, USA.
4 //#
5 //# This library is free software; you can redistribute it and/or modify it
6 //# under the terms of the GNU Library General Public License as published by
7 //# the Free Software Foundation; either version 2 of the License, or (at your
8 //# option) any later version.
9 //#
10 //# This library is distributed in the hope that it will be useful, but WITHOUT
11 //# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 //# FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
13 //# License for more details.
14 //#
15 //# You should have received a copy of the GNU Library General Public License
16 //# along with this library; if not, write to the Free Software Foundation,
17 //# Inc., 675 Massachusetts Ave, Cambridge, MA 02139, USA.
18 //#
19 //# Correspondence concerning AIPS++ should be addressed as follows:
20 //# Internet email: aips2-request@nrao.edu.
21 //# Postal address: AIPS++ Project Office
22 //# National Radio Astronomy Observatory
23 //# 520 Edgemont Road
24 //# Charlottesville, VA 22903-2475 USA
25 //#
26 //# $Id$
27 
28 #ifndef LATTICES_TILEDCOLLAPSER_H
29 #define LATTICES_TILEDCOLLAPSER_H
30 
31 
32 //# Includes
33 #include <casacore/casa/aips.h>
36 
37 namespace casacore { //# NAMESPACE CASACORE - BEGIN
38 
39 //# Forward Declarations
40 class IPosition;
41 
42 // <summary>
43 // Abstract base class to collapse chunks for LatticeApply
44 // </summary>
45 
46 // <use visibility=export>
47 
48 // <reviewed reviewer="" date="yyyy/mm/dd" tests="" demos="">
49 // </reviewed>
50 
51 // <prerequisite>
52 // <li> <linkto class=LatticeApply>LatticeApply</linkto>
53 // </prerequisite>
54 
55 // <etymology>
56 // </etymology>
57 
58 // <synopsis>
59 // This is an abstract base class for the collapsing of chunks to
60 // be used in function <src>tiledApply</src>
61 // in class <linkto class=LatticeApply>LatticeApply</linkto>.
62 // It is meant for cases where an entire line or plane is not needed
63 // (e.g. calculation of maximum). If that is needed (e.g. to calculate moment),
64 // it is better to use function <src>LatticeApply::lineApply</src>
65 // with class <linkto class=LineCollapser>LineCollapser</linkto>.
66 // <p>
67 // The user has to derive a concrete class from this base class
68 // and implement the (pure) virtual functions.
69 // <br> The main function is <src>process</src>, which needs to do the
70 // calculation.
71 // <br> Other functions make it possible to perform an initial check.
72 // <p>
73 // The class is Doubly templated. Ths first template type
74 // is for the data type you are processing. The second type is
75 // for what type you want the results of the processing assigned to.
76 // For example, if you are computing sums of squares for statistical
77 // purposes, you might use higher precision (FLoat->Double) for this.
78 // No check is made that the template types are self-consistent.
79 // </synopsis>
80 
81 // <example>
82 // <srcblock>
83 // </srcblock>
84 // </example>
85 
86 // <motivation>
87 // </motivation>
88 
89 // <todo asof="1997/08/01">
90 // <li>
91 // </todo>
92 
93 
94 template <class T, class U=T> class TiledCollapser
95 {
96 public:
97 
98 // Destructor
99  virtual ~TiledCollapser();
100 
101 // The init function for a derived class.
102 // It can be used to check if <src>nOutPixelsPerCollapse</src>
103 // corresponds with the number of pixels produced per collapsed chunk.
104 // <br><src>processAxis</src> is the axis of the line being passed
105 // to the <src>process</src> function.
106  virtual void init (uInt nOutPixelsPerCollapse) = 0;
107 
108 // Can the process function in the derived class handle a null mask pointer?
109 // If not, LatticeApply ensures that it'll always pass a mask block,
110 // even if the lattice does not have a mask (in that case that mask block
111 // contains all True values).
112 // <br>The default implementation returns False.
113 // <br>The function is there to make optimization possible when no masks
114 // are involved. On the other side, it allows the casual user to ignore
115 // optimization.
116  virtual Bool canHandleNullMask() const;
117 
118 // Create and initialize the accumulator.
119 // The accumulator can be a cube with shape [n1,n2,n3],
120 // where <src>n2</src> is equal to <src>nOutPixelsPerCollapse</src>.
121 // However, one can also use several matrices as accumulator.
122 // <br> The data type of the accumulator can be any. E.g. when
123 // accumulating Float lattices, the accumulator could be of
124 // type Double to have enough precision.
125 // <br>In the <src>endAccumulator</src> function the accumulator
126 // data has to be copied into an Array object with the correct
127 // shape and data type.
128  virtual void initAccumulator (uInt64 n1, uInt64 n3) = 0;
129 
130 // Collapse the given input data containing (<src>nrval</src> values
131 // with an increment of <src>inDataIncr</src> elements).
132 // <src>inMask</src> is a Bool block representing a mask with the
133 // same nr of values and increment as the input data. If a mask
134 // value is False, the corresponding input value is masked off.
135 // <br>When function <src>canHandleNullMask</src> returned True,
136 // it is possible that <src>inMask</src> is a null pointer indicating
137 // that the input has no mask, thus all values are valid.
138 // <br>
139 // The result(s) have to be stored in the accumulator at the given indices.
140 // <br><src>startPos</src> gives the lattice position of the first value.
141 // The position of other values can be calculated from index and shape
142 // using function <src>toPositionInArray</src> in class
143 // <linkto class=IPosition>IPosition</linkto>.
144  virtual void process (uInt accumIndex1, uInt accumIndex3,
145  const T* inData, const Bool* inMask,
146  uInt inDataIncr, uInt inMaskIncr,
147  uInt nrval,
148  const IPosition& startPos,
149  const IPosition& shape) = 0;
150 
151 // End the accumulator. It should return the accumulator as an
152 // Array of datatype U (e.g. double the precision of type T)
153 // with the given shape. The accumulator should thereafter be deleted when needed.
154  virtual void endAccumulator (Array<U>& result,
155  Array<Bool>& resultMask,
156  const IPosition& shape) = 0;
157 };
158 
159 
160 
161 } //# NAMESPACE CASACORE - END
162 
163 #ifndef CASACORE_NO_AUTO_TEMPLATES
164 #include <casacore/lattices/LatticeMath/TiledCollapser.tcc>
165 #endif //# CASACORE_NO_AUTO_TEMPLATES
166 #endif
unsigned long long uInt64
Definition: aipsxtype.h:39
virtual void initAccumulator(uInt64 n1, uInt64 n3)=0
Create and initialize the accumulator.
virtual void endAccumulator(Array< U > &result, Array< Bool > &resultMask, const IPosition &shape)=0
End the accumulator.
virtual Bool canHandleNullMask() const
Can the process function in the derived class handle a null mask pointer? If not, LatticeApply ensure...
bool Bool
Define the standard types used by Casacore.
Definition: aipstype.h:42
TableExprNode shape(const TableExprNode &array)
Function operating on any scalar or array resulting in a Double array containing the shape...
Definition: ExprNode.h:1987
virtual void init(uInt nOutPixelsPerCollapse)=0
The init function for a derived class.
virtual ~TiledCollapser()
Destructor.
virtual void process(uInt accumIndex1, uInt accumIndex3, const T *inData, const Bool *inMask, uInt inDataIncr, uInt inMaskIncr, uInt nrval, const IPosition &startPos, const IPosition &shape)=0
Collapse the given input data containing (nrval values with an increment of inDataIncr elements)...
unsigned int uInt
Definition: aipstype.h:51