Computer Programs
USCD1040 BAYESZ.
last modified: 07-OCT-1982 | catalog | categories | new | search |

USCD1040 BAYESZ.

BAYESZ, S-Wave, P-Wave Resonance Level Spacing and Strength Functions

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1. NAME OR DESIGNATION OF PROGRAM:  BAYESZ.
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2. COMPUTERS
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Program name Package id Status Status date
BAYESZ USCD1040/02 Tested 07-OCT-1982

Machines used:

Package ID Orig. computer Test computer
USCD1040/02 CRAY 1 CRAY 1
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3. DESCRIPTION OF PROBLEM OR FUNCTION

BAYESZ calculates average s- and p-wave level spacings, strength functions, and average radiation widths of a mixed sequence of s- and p-wave resonances whose parameters are supplied as input. The code is based on two physical  assumptions:

1) The neutron reduced width distribution for each open channel is  a chi-squared distribution with one degree of freedom, i.e.     Porter-Thomas.

2) The spacing distribution follows the Gaussian Orthogonal  Ensemble. This property is used, however, only to fix the s- to  p-wave level density ratio as proportional to (2J+1) with a spin     cut-off correction.
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4. METHOD OF SOLUTION

The method used is an extension of that described by Moore et al. in reference (1), and is based on the method of moments of a truncated Porter-Thomas distribution.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Parameters for a maximum of 500 individual resonances can be specified. This restriction can be relaxed by increasing array dimensions.
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6. TYPICAL RUNNING TIME

About 2 seconds of CRAY-1 CP time are required for 10 iterations on a set of parameters for 273 resonances. A similar problem required 18 seconds on a CDC-7600 to perform 20 iterations.
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7. UNUSUAL FEATURES OF THE PROGRAM

The program requires no subjective judgement on the part of the user to interpret the results; all input initial guess values for average parameters are automatically  adjusted during the iteration procedure.
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8. RELATED AND AUXILIARY PROGRAMS:  BAYESZ is an extension of BAYESX.
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9. STATUS
Package ID Status date Status
USCD1040/02 07-OCT-1982 Tested at NEADB
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10. REFERENCES

(1) M.S. Moore et al.:
    Spin Determination of Resonance Structure in (U-235 + n)
    Below 25 keV.
    Phys. Rev. C18, 1328 (September, 1978).
USCD1040/02, included references:
- Program Description, BAYESZ
  P-3/81-886 0372R (December 4, 1981).
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11. MACHINE REQUIREMENTS:  51200 words on a CRAY-1.
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
USCD1040/02 FORTRAN-IV
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  COS.
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:
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15. NAME AND ESTABLISHMENT OF AUTHOR

          Dr. M.S. Moore
          Los Alamos National Laboratory
          Los Alamos
          New Mexico 87545
          USA
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16. MATERIAL AVAILABLE
USCD1040/02
File name File description Records
USCD1040_02.003 BAYESZ INFORMATION FILE 83
USCD1040_02.004 BAYESZ SOURCE (FORTRAN-4) 443
USCD1040_02.005 BAYESZ JCL FOR COMPILATION & LINKEDIT 10
USCD1040_02.006 BAYESZ JCL TO RUN TEST CASES 12
USCD1040_02.007 BAYESZ INPUT DATA FOR TEST CASE 1 262
USCD1040_02.008 BAYESZ OUTPUT OF TEST CASE 1 695
USCD1040_02.009 BAYESZ INPUT DATA FOR TEST CASE 2 260
USCD1040_02.010 BAYESZ OUTPUT OF TEST CASE 2 1121
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17. CATEGORIES
  • A. Cross Section and Resonance Integral Calculations

Keywords: nuclear models, porter-thomas distribution, resolved region, resonance.