DESCRIPTION

• twist (formerly called squeeze) is a compression tool tailored for fields where node-to-node variations are small, and where undefined (dry) nodes are abundant
• twist stores data using two byte integers, hence, there's generally a loss of accuracy
• squeeze contains the subroutines that make up the "heart" of twist
• the decompression tool is release
• scipts are included for compression (twist.sh), and decompression (release.sh), of binary dump files; the loss of accuracy may be checked (accrcy_loss.sh)

CORE SOURCE CODE

• squeeze.f
• speedsqueeze.f
• release.f
• twist.f

SOURCE CODE FOR COMPRESSION OF IEEE FILES

• accrcy_loss.f
• checkname.f
• releaseIEEE.f
• release_dims.f
• strings.f
• twistIEEEi2.f
• twistIEEEi4.f
• twistIEEEr4.f
• twist_info.f

• accrcy_loss.make
• checkname.make
• releaseIEEE.make
• release_dims.make
• twistIEEEi2.make
• twistIEEEi4.make
• twistIEEEr4.make
• twist_info.make

• accrcy_loss.sh
• release.sh
• twist.sh

SAMPLE PROGRAMS

• L_rndm.f77 ("LINUX" version)
• S_rndm.f77 ("SGI" version)
• Tmultitest.f
• Tsqueeze.f
• Ttwist.f
• random_seq.f
• release_seq.f
• twist_seq.f

• Tmultitest.make
• Tsqueeze.make
• Ttwist.make
• linux.head ("head" include file for make files; LINUX version)
• linux.tail ("tail" include file for make files; LINUX version)
• random_seq.make
• release_seq.make
• sgi.head ("head" include file for make files; SGI version)
• sgi.tail ("tail" include file for make files; SGI version)
• twist_seq.make

DOCUMENTATION

• squeeze
• squeeze/sample, a "walk-thru" of "squeeze"
• speedsqueeze
• release
• release/sample, a "walk-thru" of "release"
• twist
• accrcy_loss.sh
• random_seq.sh
• release.sh
• twist.sh

DOWNLOAD

VERSION HISTORY

• Version 1.0: Original version released June 24, 1998
• Version 1.1: New version released March 2, 1999.
  New features:
  1. Included documentation in HTML-format
  2. Included compression algorithm no. 6
  3. Eliminated one minor bug
  4. Decompression tool renamed; to 'release'
• Version 2.0: New version released April 12, 1999
  New features:
  1. Included 'twist' for optimal compression
  2. Included compression algorithm no. 9
  3. Included compression algorithm no. 1
  4. Several bugs eliminated
  This is the first version which has been made publicly available.
• Version 2.1: New version released May 18, 1999
  New features:
  1. Rewritten 'twist' for faster and less memory intensive compression (using 'speedsqueeze')
  2. One bug eliminated
• Version 2.1.1: Modified version released July 12, 1999
  1. Serious bug during compression using algorithm no. 1 eliminated
• Version 2.2: New version released January 5, 2000
  
  1. Included the test program "multitest"
  2. Eliminated bug in case of differences exceeding 32768 in the subroutines 'get_valueXY' on squeeze.f and 'speed_valueXY' on speedsqueeze.f
  3. Rewritten 'twist'; modification of tests for successful compression
• Version 3.0: New version released July 5, 2001
  
  1. Modified make-files to work properly on LINUX
  2. Reorganized structure of files/ directory tree, included more flexibility in the processes of installation
  3. Introduced "install_twist.sh" as a user-friendly installation interface.
  4. Adopted the use of "twist" as a term that defines this library
• Version 3.1: New version released August 27, 2001
  
  1. Included software for testing from in-house version, used by "random_seq.sh"
  2. Introduced software for compression ("twist.sh") and decompression ("release.sh") of binary dump files, accuracy loss determination ("accrcy_loss.sh"), and additional related software (e.g., "twist_info" which writes a summary of the contents of compressed binary dump files)
  3. Included brief on-line descriptions of some scripts

DISCLAIMER

I TAKE NO RESPONSIBILITY OF THE USE OF THE COMPRESSION AND DECOMPRESSION TOOLS. THE USER SHOULD KEEP A BACK-UP OF THE ORIGINAL RESULTS AS A SAFEGUARD AGAINST ANY PROGRAMMING ERRORS.

... however, if a problem occurs, please do not hesitate to inform me, and I'll do my best to help you out!