[casacore] r21242 committed - Added an example
casa...@googlecode.com
Author: gervandiepen
Date: Thu Apr 12 06:38:34 2012
Log: Added an example
http://code.google.com/p/casacore/source/detail?r=21242
Modified:
/doc/notes/199.dir/taql.tex
=======================================
--- /doc/notes/199.dir/taql.tex Sat Dec 31 08:25:02 2011
+++ /doc/notes/199.dir/taql.tex Thu Apr 12 06:38:34 2012
@@ -51,7 +51,7 @@
language style to be used.
\item The language can be extended by means of User Defined
Functions. Some standard UDFs exist to deal with measure conversions
- (for directions, epochs, and positions).
+ (for directions, epochs, positions, and stokes).
\end{itemize}
TaQL has a keyword that makes it possible to time the various parts of
a TaQL command.
@@ -457,7 +457,7 @@
Note that if using \texttt{IN}, the shorthand has to preceed
the table name. It can be seen as an iterator variable.
-There are three special ways to specify a table:
+There are four special ways to specify a table:
\begin{enumerate}
\item
@@ -489,6 +489,15 @@
that shorthand are taken into account. If no shorthand is
given, only primary tables are taken into account.
+\item
+Opening a subtable using a path name like \texttt{my.ms/ANTENNA}
+will fail if \texttt{my.ms} is a reference table instead of the
+original table.
+Therefore the path of a subtable can be given using colons instead of
+slashes like \texttt{my.ms::ANTENNA} which is a slight extension of
+specifying table names in the previous bullet.
+\\In this way a subtable can always be found, no matter where it is
located.
+
\item
Like in OQL it is possible to use a
\htmlref{nested query}{TAQL:SUBQUERIES}
@@ -1127,7 +1136,7 @@
&
^
|
- == != > >= < <= =~ !=~ IN INCONE BETWEEN EXISTS LIKE ~ !~
+ == != > >= < <= ~= !~= IN INCONE BETWEEN EXISTS LIKE ~ !~
&&
||
\end{verbatim}
@@ -1174,10 +1183,12 @@
$<$ & no bool & comparison for less \\
$<=$ & no bool & comparison for less or equal \\
$!=$, $<>$ & all & comparison for not equal \\
- $=~$ is a shorthand for the \htmlref{NEAR
function}{TAQL:COMPARISONFUNCTIONS}
- with a tolerance of 1e-5.
- $!=~$ is a shorthand for NOT \htmlref{NEAR}{TAQL:COMPARISONFUNCTIONS}
- with a tolerance of 1e-5.
+ \verb+~=+ & numeric & shorthand for the
+ \htmlref{NEAR function}{TAQL:COMPARISONFUNCTIONS}
+ with a tolerance of 1e-5 \\
+ \verb+!~=+ & numeric & shorthand for NOT
+ \htmlref{NEAR}{TAQL:COMPARISONFUNCTIONS}
+ with a tolerance of 1e-5 \\
\texttt{\&\&}, AND & bool & logical and \\
\verb+||+, OR & bool & logical or \\
\texttt{!}, NOT & bool & logical not \\
@@ -1195,7 +1206,7 @@
(See the discussion of \htmlref{sets}{TAQL:SETS}). \\
NOT IN & all & negation of IN \\
BETWEEN & no bool & \texttt{a BETWEEN b AND c} is similar to
- \texttt{a>=b AND a<=c} and \texttt{a IN [b:=:c]} \\
+ \texttt{a>=b AND a<=c} and \texttt{a IN [b=:=c]} \\
NOT BETWEEN & no bool & \texttt{a NOT BETWEEN b AND c} is negation
of above. \\
INCONE & & cone search. (See the discussion of
@@ -1505,21 +1516,21 @@
Removes trailing whitespace.
\item[] \texttt{string TRIM(string)}\\
Removes leading and trailing whitespace.
- \item[] \texttt{string SUBSTR(string, integer ST, integer N)}
+ \item[] \texttt{string SUBSTR(string, integer ST, integer N)}\\
Returns a substring starting at the 0-based position
\texttt{ST} with a length of at most \texttt{N} characters.
If the string argument is an array of strings, an array with the
substring of each
string is returned. The arguments N and ST have to be scalar
values. They will be set to 0 if negative.
- \item[] \texttt{string REPLACE(string SRC, PATTERN, string REPL)}
+ \item[] \texttt{string REPLACE(string SRC, PATTERN, string REPL)}\\
Replaces all occurrences of PATTERN in SRC by REPL and returns the
result. REPL can be omitted and defaults to the empty string.
If the first argument is an array of strings, each element in the
array is replaced.
The arguments PATTERN and REPL have to be scalar values. PATTERN
can be a string or a regular expression (see below). For example:
- \\\verb+REPLACE(''abcdab'', "ab'')+ results in \texttt{cd}
- \\\verb+REPLACE(''abcdab'', REGEX("^ab''), "xyz"')+ results in
\texttt{xyzcdab}
+ \\\verb+REPLACE("abcdab", "ab")+ results in \texttt{cd}
+ \\\verb+REPLACE("abcdab", REGEX("^ab"), "xyz")+ results in
\texttt{xyzcdab}
\end{description}
\subsubsection{Regex functions}
@@ -2013,8 +2024,8 @@
one or more cones (e.g. as RA,DEC,radius).
Usually the user will specify it as constants.
\\For example:
- \\\texttt{[12:13:54, -5.3.34, 0d1m]} for a single cone.
- \\\texttt{[12:13:54, -5.3.34, 0d1m, 1:2:3, 4.5.6, 0d1m]} for two
cones.
+ \\\texttt{[12h13m54, -5.3.34, 0d1m]} for a single cone.
+ \\\texttt{[12h13m54, -5.3.34, 0d1m, 1h2m3, 4.5.6, 0d1m]} for two
cones.
\item[] \texttt{CONEPOS}\\
is a set or array giving the positions of one or more
cone centers (e.g. as RA,DEC).
@@ -2025,7 +2036,7 @@
it as \texttt{CONES} if the same radius has to be used for
multiple cones.
\\For example:
- \\\texttt{[12:13:54, -5.3.34, 1:2:3, 4.5.6], 0d1m} is the same
+ \\\texttt{[12h13m54, -5.3.34, 1h2m3, 4.5.6], 0d1m} is the same
as the second \texttt{CONES} example above.
\end{description}
The following cone search functions are available.
@@ -2197,6 +2208,13 @@
\item PANGLE is the linear polarization angle (0.5*arctan(U/Q)) (in
radians)
\end{itemize}
If not given, the string argument defaults to 'IQUV'.
+For example:
+\begin{verbatim}
+ select mscal.stokes(DATA,'circ') as CIRCDATA from my.ms
+\end{verbatim}
+creates a table with column CIRCDATA containing the circular
+polarization data.
+
\subsubsection{\label{TAQL:MEASFUNC}Special Measures functions}
These functions make it possible to convert measures like directions,