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SampledFunctional.h
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1 //# SampledFunctional.h:
2 //# Copyright (C) 1996,1999
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
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25 //#
26 //# $Id$
27 
28 #ifndef SCIMATH_SAMPLEDFUNCTIONAL_H
29 #define SCIMATH_SAMPLEDFUNCTIONAL_H
30 
31 #include <casacore/casa/aips.h>
33 
34 namespace casacore { //# NAMESPACE CASACORE - BEGIN
35 
36 // <summary> A base class for indexing into arbitrary data types </summary>
37 
38 // <use visibility=export>
39 
40 // <reviewed reviewer="wyoung" date="1996/10/10" tests="tSampledFunctional.cc">
41 
42 // <prerequisite>
43 // <li> Functional
44 // </prerequisite>
45 
46 // <etymology>
47 // A Functional is simply a mapping from a Domain type to a Range
48 // type. Experimental data is usually sampled, and is can be represented as
49 // a mapping from the unsigned integers to an arbitrary Domain.
50 // </etymology>
51 
52 // <synopsis>
53 // This abstract class defines an interface for functions that map from the
54 // unsigned integers to an arbitrary type. It defines two functions: the
55 // operator() function which it inherits from the Functional class, and the
56 // nelements function which is necessary to know how many data elements.
57 //
58 // This class is useful for freeing the writer of other classes from having
59 // to know how how a linear data set is stored or represented. For example,
60 // four floating point numbers will probably be stored as a Vector<Float>,
61 // and kept in memory for fast access. But 400 million floating point
62 // numbers cannot usually be kept in memory, and may be stored on disk as a
63 // Table. By using a SampledFunctional writers of other classes
64 // (Interpolate1D is an example), can ignore these details if all they are
65 // interested in is random access to individual elements of the data.
66 // </synopsis>
67 
68 // <example>
69 // Because this is an abstract class the example will be inside a function
70 // <srcblock>
71 // T sum(SampledFunctional<T> data)
72 // {
73 // T result = 0;
74 // for (uInt i = 0; i < data.nelements(); i++)
75 // result += data(i);
76 // return result;
77 // }
78 // </srcblock>
79 // </example>
80 
81 // <motivation>
82 // If all you need to do is random access indexing into arbitrary data sets
83 // this class provides a suitable abstraction of that functionality.
84 // </motivation>
85 
86 // <templating arg=Range>
87 // <li> Templating restrictions will depend on the actual derived class that is
88 // used.
89 // </templating>
90 
91 // <thrown>
92 // <li> Exceptions will depend on derived classes and the templating
93 // arguements. This abstract class only defines an interface and does not
94 // throw any exceptions.
95 // </thrown>
96 
97 // <todo asof="1996/10/19">
98 // <li> I cannot think of anything
99 // </todo>
100 
101 template <class Range> class SampledFunctional:
102  public Functional<uInt, Range>
103 {
104 public:
105  // Access the specified element of the data
106  virtual Range operator()(const uInt &index) const = 0;
107  // Return the total size of the data set.
108  virtual uInt nelements() const = 0;
109  // The virtual destructor does nothing
110  virtual ~SampledFunctional(){}
111 };
112 
113 
114 } //# NAMESPACE CASACORE - END
115 
116 #endif
virtual Range operator()(const uInt &index) const =0
Access the specified element of the data.
Map a domain object into a range object via operator().
Definition: Functional.h:122
virtual uInt nelements() const =0
Return the total size of the data set.
A base class for indexing into arbitrary data types.
virtual ~SampledFunctional()
The virtual destructor does nothing.
unsigned int uInt
Definition: aipstype.h:51
#define casacore
&lt;X11/Intrinsic.h&gt; #defines true, false, casacore::Bool, and String.
Definition: X11Intrinsic.h:42