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MeasEngine.h
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1//# MeasEngine.h: Templated base class for the TaQL UDF conversion engines
2//# Copyright (C) 2018
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 MEAS_MEASENGINE_H
29#define MEAS_MEASENGINE_H
30
31//# Includes
32#include <casacore/casa/aips.h>
33#include <casacore/meas/MeasUDF/BaseEngine.h>
34#include <casacore/measures/TableMeasures/ScalarMeasColumn.h>
35#include <casacore/measures/TableMeasures/ArrayMeasColumn.h>
36#include <casacore/casa/Arrays/Array.h>
37
38namespace casacore {
39
40 // <summary>
41 // Templated base class for the TaQL UDF conversion engines
42 // </summary>
43
44 // <use visibility=export>
45
46 // <reviewed reviewer="" date="" tests="tMeas.cc">
47 // </reviewed>
48
49 // <prerequisite>
50 //# Classes you should understand before using this one.
51 // <li> BaseEngine
52 // </prerequisite>
53
54 // <synopsis>
55 // DopplerEngine defines Engines (user defined functions) that can be used
56 // in TaQL to convert Measures for dopplers.
57 // In this way such derived values appear to be ordinary TaQL functions.
58 //
59 // Doppler conversions require a MeasFrame containing sky direction,
60 // epoch and position on earth.
61 // In TaQL these functions can be called like:
62 // <srcblock>
63 // meas.rv ('TOPO', 1 'm/s', 'LSRK', 'CasA', date(),
64 // [1e6m,1e6m,1e6m], 'WGS84')
65 // </srcblock>
66 // which converts the dopplers from LSRK to TOPO.
67 // <ul>
68 // <li>
69 // <src>toref</src> is a single constant string.
70 // <li>
71 // <src>pos</src> can have various value types. A single numeric array is
72 // a series of RA,DEC in J2000. If given as a set, the last argument of the
73 // set can be the reference types of the values in the set. The values can
74 // be strings (indicating planetary objects) or value pairs giving lon,lat.
75 // The default reference type is J2000.
76 // </ul>
77 // All such functions return data with type double and unit Hz.
78 //
79 // Dopplers can be given like:
80 // [v1,v2,...], fromRef
81 // where fromRef is the reference type.
82 //
83 // A doppler can also be a table column which usually knows its type.
84 // It can also be an expression (e.g. DOPPLER[0,]) which also knows the type.
85 // </synopsis>
86
87 // <motivation>
88 // It makes it possible to handle measures in TaQL.
89 // </motivation>
90
91 template <typename M>
92 class MeasEngine: public BaseEngine
93 {
94 public:
96 : itsRefType (M::N_Types)
97 {}
98
99 virtual ~MeasEngine();
100
101 // Get the reference type.
102 typename M::Types refType() const
103 { return itsRefType; }
104
105 // Handle a doppler reference type.
106 // If the reference type is invalid, an exception is only thrown
107 // if <src>doThrow=True</src>. In this way a string argument can
108 // be a source name for a direction.
109 Bool handleMeasType (const TENShPtr& operand, Bool doThrow);
110
111 // Make the expression result attributes.
112 Record makeAttributes (typename M::Types refType,
113 Int valueType = 1) const;
114
115 protected:
116 // Handle the operand representing an array of Meas values.
117 void handleMeasArray (const TENShPtr& operand);
118
119 // Handle a constant Meas value.
120 void handleConstant (const TENShPtr& operand);
121
122 // Let a derive class handle the values.
123 virtual void handleValues (TableExprNode& operand,
124 const TableExprId& id,
125 Array<M>& positions) = 0;
126
127 //# Data members.
129 typename M::Types itsRefType;
132 };
133
134} //end namespace
135
136
137#ifndef CASACORE_NO_AUTO_TEMPLATES
138#include <casacore/meas/MeasUDF/MeasEngine.tcc>
139#endif //# CASACORE_NO_AUTO_TEMPLATES
140#endif
Bool handleMeasType(const TENShPtr &operand, Bool doThrow)
Handle a doppler reference type.
M::Types refType() const
Get the reference type.
Definition MeasEngine.h:102
virtual void handleValues(TableExprNode &operand, const TableExprId &id, Array< M > &positions)=0
Let a derive class handle the values.
Array< M > itsConstants
Definition MeasEngine.h:128
ArrayMeasColumn< M > itsMeasArrCol
Definition MeasEngine.h:131
Record makeAttributes(typename M::Types refType, Int valueType=1) const
Make the expression result attributes.
void handleMeasArray(const TENShPtr &operand)
Handle the operand representing an array of Meas values.
ScalarMeasColumn< M > itsMeasScaCol
Definition MeasEngine.h:130
void handleConstant(const TENShPtr &operand)
Handle a constant Meas value.
this file contains all the compiler specific defines
Definition mainpage.dox:28
int Int
Definition aipstype.h:50
bool Bool
Define the standard types used by Casacore.
Definition aipstype.h:42