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Last modified: 13 December 2013

URL: http://cxc.harvard.edu/ciao/watchout.html

CIAO "Watch Out" Page

This page lists noteworthy items and issues about the CIAO 4.6 release. For the full list of known issues please review the:


Installing & Starting CIAO

[New]Problems starting sherpa with HEAsoft

Users who try to run CIAO and FTOOLs on Linux machines in the same terminal may get an error like

unix% sherpa
-----------------------------------------------------
Welcome to Sherpa: CXC's Modeling and Fitting Package
-----------------------------------------------------
CIAO 4.6 Sherpa version 1 Monday, December 2, 2013

WARNING: failed to import sherpa.astro.xspec; XSPEC models will not be available
sherpa-1>

To work around the problem, users must set the following environment variable

  (tcsh) :  setenv CIAO_LD_LIBRARY_PATH $ASCDS_INSTALL/ots/lib
  (bash) :  export CIAO_LD_LIBRARY_PATH=$ASCDS_INSTALL/ots/lib

This should be done after the CIAO setup and before starting sherpa. This does not affect Mac OSX users.

Parameter file conflicts with HEAsoft

Both CIAO and FTOOLS use parameter files to store parameter values for tools, and provide tools for manipulating these files (e.g. plist, pset, punlearn; they have the same name in both systems). The location of the parameter files is taken from the $PFILES environment variables for CIAO and FTOOLS (or $UPARM if $PFILES does not exist).

Common errors are:

pget: could not get parameter "foo"

and

The following parameter:
    "foo,b,l,no,,,"Keyword""
has the following error(s):
  o Mode field "l" is invalid.

and

The following parameter:
"foo,i,h,INDEF,INDEF,INDEF,"description""
has the following error(s):
o Problem converting minimum field "INDEF" to parameter type "i".
o Problem converting maximum field "INDEF" to parameter type "i".

We recommend that you start FTOOLS before CIAO to minimize conflicts; more information on this problem is available in the CIAO and FTOOLS section of the Starting CIAO thread. Also refer to the related FAQ "The tool is failing because ")sval" has somehow shown up in the parameter value.".

Conflicts with Other Software Packages

There are some known conflicts between CIAO and other software or system libraries and tools. Issues not covered in this "Watch Out" page are listed on the "Other Software Packages" bug page.


Analysis

[New]pbkfile parameter deprecated

In CIAO 4.6 the pbkfile parameter has become obsolete in the following tools:

and has been removed entirely from the following high level scripts

This change has been made possible by the additon of a set of new keywords to the Chandra data products during the last bulk reprocessing of most of the data in the Chandra archive (internally known as Repro-4). Only the data from the first few months of the mission were omitted.

Users retrieving data directly from the archive and using the high level scripts to generate responses will not need to make any changes. Users whose workflow calls the individual tools mentioned above, need to be sure that the obsfile (for mkarf, mkgarf, mkinstmap) or infile (for mkwarf, eff2evt, mean_energy_map) input is an event file or a file derived from the event file. The aspect solution and aspect histograms do not contain the needed metadata.

However, users with old version of data products, created with software version earlier than ASCDSVER = 8.4.2, will need to update their files in order to use CIAO 4.6.

There are 3 options available:

  • Retrieve the lastest version of the data products from the Chandra archive. There are many cumulative changes that have been made to the processing system including new aspect "drift" calibrations and timing corrections that are only available in the latest processed version. Users can use download_chandra_obsid to retrieve the latest version.

  • Apply the lastest calibrations with the CIAO 4.6 version of chandra_repro which will automatically add the new keywords.

  • Finally, if it is undesireable to update calibrations or data products, user can simply update the existing meta-data in their old data files using the r4_header_update script.

For reference, the keywords that were added are: OCLKPAIR, ORC_MODE ,SUM_2X2, and FEP_CCD. The first 3 are simply copied from the ACIS parameter block file associated with the observation; the last is a string-encoded value mapping CCDs to the different sets of electronics.

Specifying Aspect Solution Files

The aspect solution files (pcad..._asol1.fits) are used as inputs to several of the CIAO tools - e.g. acis_process_events, asphist, and tg_resolve_events.

If there is a single aspect solution file, it can be provided directly to the tool:

unix% pset asphist infile=pcadf245733620N002_asol1.fits

In many cases, there will be more than one aspect solution file for an observation. Then all the files must be provided in chronological order. (The time is in the filename, so "ls" lists them in chronological order.) This may be done as a comma-separated list:

unix% pset asphist infile="pcadf063874624N002_asol1.fits,pcadf063875522N002_asol1.fits,pcadf063902942N002_asol1.fits"

The list of aspect solution files may also be given as a stack. Any number of files can be specified in the stack, one:

unix% cat pcad_asol1.lis
pcadf245733620N002_asol1.fits

unix% pset asphist infile=@pcad_asol1.lis

or more than one:

unix% cat pcad_asol1.lis
pcadf063874624N002_asol1.fits
pcadf063875522N002_asol1.fits
pcadf063902942N002_asol1.fits

unix% pset asphist infile=@pcad_asol1.lis

Note that an at symbol ("@") is used before the filename to indicate that it is a stack file.

Incorrect GTIs when time-filtering grating data with dmcopy opt=all

When a time filter is applied to a level=1.5 (evt1a.fits) or level=2 (evt2.fits) grating file and the dmcopy opt=all option is used, the GTI block in the output file is not updated to reflect the correct time range. Time-related header keyword values - such as ontime, livetime, and exposure - will be incorrect because they are calculated from the time ranges in the GTI block.

This time-filtering is one of the standard reprocessing steps for grating data, so anyone that reprocesses a grating dataset in CIAO 4.5 is affected.

This bug affects all ACIS and HRC grating data analysis. Read the bug report for details and a workaround.


Last modified: 13 December 2013
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