Computer Programs
NEA-1895 ENDSAM.
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NEA-1895 ENDSAM.

ENDSAM, a code for random sampling and validation of covariance data of resonance parameters in ENDF-6 format

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1. NAME OR DESIGNATION OF PROGRAM

ENDSAM

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2. COMPUTERS
To submit a request, click below on the link of the version you wish to order. Rules for end-users are available here.
Program name Package id Status Status date
ENDSAM NEA-1895/01 Arrived 23-JUN-2016

Machines used:

Package ID Orig. computer Test computer
NEA-1895/01 Linux-based PC,PC Windows
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3. DESCRIPTION OF PROGRAM OR FUNCTION

ENDSAM from a nuclear data library file of a chosen isotope in ENDF-6 format produces an arbitrary number of new files in ENDF-6 format which contain values of randomly sampled resonance parameters (in accordance with corresponding covariance matrices) in places of original values. The program works in the following steps:

  • reads resonance parameters and their covariance data from nuclear data libraries,

  • checks the consistency and mathematical correctness of the covariance data,

  • produces files containing randomly sampled resonance parameters.

 

Parameters are sampled according to the following distributions:

  • normal (resonance energy),

  • lognormal, multiplied with -1 (fission width, if it has negative mean value),

  • lognormal (all other parameters).

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4. METHODS

Random samples of resonance parameters are generated with transformation of correlation coefficients [5] and standard methods using Cholesky decomposition of correlation matrix and Box-Muller method [1] for generation of normally distributed random samples.

Due to the inconsistencies in nuclear data library, two issues may occur.

  • After transformation of correlation coefficients some correlations may not lie between -1 and 1. In this case original correlation matrix obtained from the library is used instead of the transformed one.

  • The transformed correlation matrix has the entries between -1 and 1, but is not positive definite. Then, in order to assure the existence of Cholesky decomposition, the correlation matrix is corrected by applying the Higham’s method [2] for calculating nearest positive definite correlation matrix.

The complete method is described in [3] and [4].

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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Number of sampled resonance parameters is limited only to computer memory capacity. Number of samples is limited only to the number of files which can be opened simultaneously. The code is so far restricted to one isotope provided in ENDF-6 format.

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6. TYPICAL RUNNING TIME

Memory used: up to 300MB.

 

Typical execution time ranges from a fraction of second up to few minutes per isotope on a PC.

If correlation matrix has many negative eigenvalues, then calculation of nearest positive definite correlation matrix may be time consuming. Otherwise, most of execution time is due to writing of resulting library files.

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8. RELATED OR AUXILIARY PROGRAMS

Routines from LAPACK and BLAS libraries are used.

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9. STATUS
Package ID Status date Status
NEA-1895/01 23-JUN-2016 Masterfiled Arrived
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10. REFERENCES
  1. G.E.P. Box, M.E. Muller, A Note on the Generation of Random Normal Deviates, Ann. Math. Stat. 29, 610-611 (1958).

  2. N.J. Higham, Computing the nearest correlation matrix -- a problem from finance, IMA J. Numer. Anal. 22, 329-343 (2002).

  3. L. Plevnik, G. Žerovnik, A computer code for random sampling of resonance parameters and validation of the resonance parameters' covariance matrices of some major nuclear data libraries, IJS-DP-11939, Jožef Stefan Institute, Ljubljana, Slovenia, 2015.

  4. L. Plevnik, G. Žerovnik, Computer code ENDSAM for random sampling and validation of the resonance parameters covariance matrices of some major nuclear data libraries, Ann. Nucl. Energy 94, 510-517 (2016)

  5. G. Žerovnik, A. Trkov, D.L. Smith, R. Capote, Transformation of correlation coefficients between normal and lognormal distribution and implications for nuclear applications, Nucl. Instr. Meth. A 727, 33-39 (2013).

NEA-1895/01, included references:
- Lucijan Plevnik: "ENDSAM manual"
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
NEA-1895/01 FORTRAN-95
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13. SOFTWARE REQUIREMENTS

Windows/Linux.

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15. NAME AND ESTABLISHMENT OF AUTHORS

Lucijan Plevnik

Institute Jožef Stefan

Jamova 39

1000 Ljubljana

Slovenia

lucijan.plevnik[at]ijs.si

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16. MATERIAL AVAILABLE
NEA-1895/01
ENDSAM_Manual.pdf                user manual
endsam.f90                       source code
min_lapack_blas\*.f              minimal set of routines from LAPACK and
                                 BLAS libraries needed for compilation
input_endsam                     sample input file
ENDF files\n-011_Na_023.endf     sample input library files
          \n-1-H-001.jeff32
          \n-25-Mn-055.jeff32
ENDF files\n-011_Na_023_1.endf   sample output library files
          \n-011_Na_023_2.endf
          \n-25-Mn-055_1.jeff32
          \n-25-Mn-055_2.jeff32
output_screen.txt                sample output information
comp_gfort.txt                   commands for compilation in command
comp_ifort.txt                   prompt with compilers GFORTRAN, INTEL
comp_lahey.txt                   FORTRAN, and LAHEY, respectively
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17. CATEGORIES
  • A. Cross Section and Resonance Integral Calculations
  • P. General Mathematical and Computing System Routines

Keywords: ENDF-6, nuclear data, random sampling, resonance parameters.