3. DESCRIPTION OF PROGRAM OR FUNCTION
The PUFF-IV code system processes ENDF/B-VI formatted nuclear cross section covariance data into multigroup covariance matrices. PUFF-IV is the newest release in this series of codes used to process ENDF uncertainty information and to generate the desired multi-group correlation matrix for the evaluation of interest. PUFF-IV enhances support for resonance parameter covariance formats described in the ENDF standard and now handles almost all resonance parameter covariance information in the resolved region, with the exception of the long range covariance sub-subsections. It is written in Fortran 90 and allows for a more modular design, thus facilitating future upgrades. This version supersedes the previous release PUFF IV, Version 1.0.2, and includes several corrections and enhancements.
- Various bug fixes concerning calculation of derivatives and group averaging of derivatives
- Improved processing of lrf=7 covariance matrices
- Support for BLAS to decrease computation time in the resolved resonance range
- Support for user defined flux functions
- Module covcomp has additional functionality for comparing and adding coverx formatted files
- Module coverr allows to convert COVERX files to NJOY covariances tapes
PUFF-IV is normally used in conjunction with an AMPX master library containing group averaged cross section data. Two utility modules are included in this package to facilitate the data interface. The module SMILER allows one to use NJOY generated GENDF files containing group averaged cross section data in conjunction with PUFF-IV. The module COVCOMP allows one to compare two files written in COVERX format.