tbcalc: Do arithmetic on a list of apphot/daophot tables databases
Package: ptools
Usage
tbcalc textfiles column value
Parameters
- textfiles
- The APPHOT/DAOPHOT ST tables database(s) containing the column to be recomputed.
- column
- The column to be recomputed. Column must be an integer or real column in the input file(s).
- value
- The arithmetic expression used to recompute the specified column. Value may be an integer or real expression but must match the data type of column.
Description
TBCALC reads in the value of the column from a set of APPHOT/DAOPHOT ST tables databases, replaces it with a new value specified by the arithmetic expression value, and updates the ST tables databases(s).
The expression value consists of variables which are column names in the APPHOT/DAOPHOT ST tables database. TBCALC uses the TABLES package task TCALC to actually perform the arithmetic operation.
The supported arithmetic operators and functions are briefly described below.
addition + subtraction -
multiplication * division /
negation - exponentiation **
absolute value abs(x) cosine cos(x)
sine sin(x) tangent tan(x)
arc cosine acos(x) arc sine asin(x)
arc tangent atan(x) arc tangent atan2(x,y)
exponential exp(x) square root sqrt(x)
natural log log(x) common log log10(x)
minimum min(x,y) maximum max(x,y)
convert to integer int(x) convert to real real(x)
nearest integer nint(x) modulo mod(x)
Examples
1. Change the XCENTER and YCENTER fields to XCENTER + 5.4 and YCENTER + 10.3 respectively in a file produced by the daophot package allstar task.
pt> tbcalc m92.als.1 xcenter "xcenter+5.4"
pt> tbcalc m92.als.1 ycenter "ycenter+10.3"
2. Add a constant to the computed magnitudes produced by the daophot package nstar task.
pt> tbcalc n4147.nst.2 mag "mag+3.457"
Bugs
See also
ptools.txcalc,tables.tcalc,ptools.pcalc