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Recent Updates to GRPPHA

Rehana Yusaf & Ian M George


Version: 1995 Feb

1 Introduction

GRPPHA is a task within the HEASARC sub-package of FTOOLS to define the channel grouping card, quality flags, and fractional systematic errors associated with a FITS PHA file. A number of other functions are also available, and a detailed description was previously reported by Yusaf & George (1994). In this document we outline a number of updates which are available in GRPPHA version 2.0.0, distributed with FTOOLS release v3.3 in late February 1995. As always, the most recent version of the GRPPHA Users Guide (memo CAL/SW/93-010) is available via anonymous ftp on as /caldb/docs/memos/cal_sw_93_010/ It is also available on the WWW at /docs/heasarc/caldb/docs/summary/cal_sw_93_010_summary.html.

2 Changes to grppha (Version 2.0.0)

Due to popular demand there are three new functions available in the latest version of GRPPHA.

2.1 Over-Writing The Input File

Users are now allowed to write an output PHA file with the same name as the input PHA file (and hence effectively over-write the input file). This can be achieved by:


  • setting the hidden boolean parameter "clobber" to yes, or
  • by making use of the "!"-convention whereby the output filename
    is preceded by an "!"
    (e.g., grppha>WRITE !INFILE.PHA)

2.2 The Dump Commands

A new "family" of command strings, DUMP, has been introduced. DUMP allows the user to write an ASCII file containing the current settings, this file may be useful if the user wishes to apply the same settings in another GRPPHA run. Currently there are 3 possible commands:

2.2.1 grppha>DUMP GROUP {filename}

The current grouping information is written to a user-defined ASCII file, each row of which lists the values of the MINCHAN MAXCHAN NCHAN for a given group. This grouping information can then be read into GRPPHA via the command grppha>GROUP {filename} (see Yusaf & George 1994, Section 3.2.2).

2.2.2 grppha>DUMP SYSTEMATICS {filename}

The current fractional systematic errors are written to a user-defined ASCII file, each row of which has the format MINCHAN MAXCHAN ERR. These systematic errors can then be read into GRPPHA via the command grppha>SYSTEMATICS {filename} (see Yusaf & George 1994, Section 3.5.2).

2.2.3 grppha>DUMP QUALITY {filename}

The current quality flags are written to a user-defined ASCII file each row of which has the format MINCHAN MAXCHAN. NOTE: Only the bad quality channels are dumped. This quality flag information can then be read into GRPPHA via the commands grppha> BAD {filename} (see Yusaf & George 1994, Sections 3.4.2 & 3.3.2). NOTE: When a GROUP MIN is applied then any spare channels at the end have their quality flag set to 2, bad defined by software. This command does not differentiate between bad channels defined by software or user (quality = 5), all non zero channels are dumped.

2.3 Enhancements to the Show Command

There have been 3 enhancements to the SHOW command:

2.3.1 grppha>SHOW INFILE

Displays the name of the input PHA file to GRPPHA.

2.3.2 grppha> SHOW CHKEYS

Displays the names of the keywords within the PHA file which can have their values changed within GRPPHA (via the command grppha> CHKEY {keyword} {new-value}; see Yusaf & George 1994, Section 3.8.1).

2.3.3 grppha> SHOW {keyword}

Displays any of the CHKEY keywords in full (even if it exceeds 80 characters). This is particularly useful for character string keywords such as the path and name of response matrices, which can often get truncated in other standard displays available within GRPPHA.


Yusaf, R., George, I.M., 1994, Legacy, 4, 64.

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