Merge two or more compatible tables (e.g. event files) into one.
dmmerge infile outfile [outBlock] [lookupTab] [columnList] [clobber]
[verbose]
`dmmerge' takes a stack of tables which have the same
columns and creates a single output table which concatenates
the input tables, so that the number of rows in the output
table is the sum of the number of rows in all the input tables.
`dmmerge' is often used to merge several event files. Note
that before merging event files, make sure that they have the
same tangent point (see `ahelp reproject_events').
This tool supports the DM stack syntax ("ahelp stack"),
meaning that the input files may be given as a comma-separated
list or as a list in a text file.
The default behavior is for dmmerge to combine all columns of
the input event files. It is possible, however, to use the DM
virtual file syntax ("ahelp dmsyntax") to select (or omit)
certain columns or rows of the files. Rather than including
the same list of columns on each input file, the columnList
parameter applies a given column filter to each file in the
input stack.
The intrinsic difficulty with this procedure is that
`dmmerge' needs to combine several input headers into one
header for the output file. A lookup table - specified in the
lookupTab parameter - describes how header keys are to be
merged.
dmmerge "file1_evt2.fits,file2_evt2.fits" merged.fits outBlock=""
columnList=""
Merge all columns in the two event files into one
output file.
dmmerge "in1.fits[events],in2.fits[events],in3.fits[events]" out.fits
outBlock="" columnList="time,chipx,chipy"
Open three input files (specifically the 'events'
block) and merge the data columns 'time,chipx,chipy'.
dmmerge "@stack.lis[events][columns time,chipx,chipy]" out.fits
outBlock="" columnList=""
Open the 'events' block of the files listed in
'stack.lis' and extract the data columns
'time,chipx,chipy' for merging. This is the same as
the previous example, but uses different syntax.
dmmerge @stack.lis out.fits outBlock="" columnList=""
Open the files listed in the stack and use all data
columns for merging.
Parameter=infile (file required filetype=input stacks=yes)
Input file name(s)
CIAO stacks may be a single filename, a comma-delimited list of
names, or '@' followed by the name of a text file containing one
filename on each line. Each filename may use the full CIAO DM
virtual file syntax.
For one or multiple input files, there should be only one single
output file.
Output block name
Output data block name. For a null string, it will use the same block
name as the first input file, which is usually what you want.
dmmerge "evt.fits[events][cols time,pha][merged_events]" columnList=""
outBlock="" is equivalent to
dmmerge "evt.fits[events]" columnList="time,pha" outBlock=merged_events
lookup table containing merging rules for header keys.
The default value is a redirect to the system version,
${ASCDS_CALIB}/dmmerge_header_lookup.txt, which enforces
CXC event pipeline header merging rules; see "plist
dmmerge" for the full path of your system default.
Each line of the file contains a keyword and a merging
rule. The rules include FORCE (always replace key),
SKIP (always omit key), WarnOmit-tol (print a warning
and omit if key valuess differ by more than tol),
WarnFirst (print warning and use first value if keys
are different), among others.
Column list
Apply a column filter to the input stack. "columnList=time,pha"
is equivalent to appending "[cols time,pha]" to each entry
in the input stack.
This parameter may also be used to omit certain
columns. "columnList=-phas" is equivalent to including
a "[cols -phas]" filter on the input files.
Clobber output if it exists? [y/n]
Parameter=verbose (integer not required default=0 min=0 max=5)
Display informational messages
The outBlock, lookupTab, and columnList parameters have been
changed to be hidden parameters. The kernel parameter has been
removed, and the verbose parameter was added.
- chandra
-
level
- concept
-
merging_rules
- dm
-
dmcols,
dmfiltering,
dmopt
- tools
-
celldetect,
dmappend,
dmarfadd,
dmgroup,
dmgti,
dmimgcalc,
dmjoin,
dmpaste,
dmsort,
dmtcalc,
dmtype2split,
tgextract
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