**RSIC COMPUTER CODE PSR-041**

**1. NAME AND TITLE**

MAZE II: Spectral Unfolding Code.

**2. CONTRIBUTORS**

Science Applications, Inc., La Jolla, California.

Gulf Radiation Technology, San Diego, California.

**3. CODING LANGUAGE AND COMPUTER**

Fortran IV; CDC 6600, UNIVAC 1108.

**4. NATURE OF PROBLEM SOLVED**

MAZE II is an unfolding code which implements the basic theory of unfolding. The two principles which underlie the theory of unfolding are that: (1) a function W of the spectrum can be found such that the unfolded spectrum corresponds to the point that minimizes W, and (2) the smoothing strength varies dynamically to the largest value that still allows the folded spectrum to be consistent with the data.

**5. METHOD OF SOLUTION**

A mathematical basis for spectral unfolding is provided by the formulation of an optimization
function, W, consisting of the sum of *a posteriori* and *a priori* information. Nonquadratic optimization
functions result in nonlinear unfoldings. A particular nonquadratic W is formulated for application to
general purpose nuclear spectral unfolding, and it is optimized by an accelerated gradient technique,
with separate handling of high and low frequency spectral components. The local variation of W about
its minimum specifies the error band of the unfolded spectrum.

**6. RESTRICTIONS OR LIMITATIONS**

None noted.

**7. TYPICAL RUNNING TIME**

No study has been made by RSIC of typical running times for MAZE II.

**8. COMPUTER HARDWARE REQUIREMENTS**

MAZE II is operable on the CDC 6600 computer (A) or the UNIVAC 1108 computer (B).

**9. COMPUTER SOFTWARE REQUIREMENTS**

A Fortran IV compiler is required.

**10. REFERENCES**

S. M. Sperling, "Spectral Unfolding: Its Mathematical Basis, Implementation and Application with MAZE2," DNA 2990F (SAI-72-574-LJ) (October 1972).

S. M. Sperling and H. Kendrick, "Numerical and Experimental Studies of Spectral Unfolding, Volume II," DASA 2720-2 (May 27, 1971).

**11. CONTENTS OF CODE PACKAGE**

Included are the referenced documents plus one (1.2MB) DOS diskette which contains the source code and sample problem input and output.

**12. DATE OF ABSTRACT**

November 1983.

**KEYWORD: ** UNFOLDING