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RSGAB(NM,N,A,B,W,MATZ,Z,FV1,FV2,IERR)

       SUBROUTINE RSGAB(NM,N,A,B,W,MATZ,Z,FV1,FV2,IERR)
 C
       INTEGER N,NM,IERR,MATZ
       DOUBLE PRECISION A(NM,N),B(NM,N),W(N),Z(NM,N),FV1(N),FV2(N)
 C
 C     THIS SUBROUTINE CALLS THE RECOMMENDED SEQUENCE OF
 C     SUBROUTINES FROM THE EIGENSYSTEM SUBROUTINE PACKAGE (EISPACK)
 C     TO FIND THE EIGENVALUES AND EIGENVECTORS (IF DESIRED)
 C     FOR THE REAL SYMMETRIC GENERALIZED EIGENPROBLEM  ABX = (LAMBDA)X.
 C
 C     ON INPUT
 C
 C        NM  MUST BE SET TO THE ROW DIMENSION OF THE TWO-DIMENSIONAL
 C        ARRAY PARAMETERS AS DECLARED IN THE CALLING PROGRAM
 C        DIMENSION STATEMENT.
 C
 C        N  IS THE ORDER OF THE MATRICES  A  AND  B.
 C
 C        A  CONTAINS A REAL SYMMETRIC MATRIX.
 C
 C        B  CONTAINS A POSITIVE DEFINITE REAL SYMMETRIC MATRIX.
 C
 C        MATZ  IS AN INTEGER VARIABLE SET EQUAL TO ZERO IF
 C        ONLY EIGENVALUES ARE DESIRED.  OTHERWISE IT IS SET TO
 C        ANY NON-ZERO INTEGER FOR BOTH EIGENVALUES AND EIGENVECTORS.
 C
 C     ON OUTPUT
 C
 C        W  CONTAINS THE EIGENVALUES IN ASCENDING ORDER.
 C
 C        Z  CONTAINS THE EIGENVECTORS IF MATZ IS NOT ZERO.
 C
 C        IERR  IS AN INTEGER OUTPUT VARIABLE SET EQUAL TO AN ERROR
 C           COMPLETION CODE DESCRIBED IN THE DOCUMENTATION FOR TQLRAT
 C           AND TQL2.  THE NORMAL COMPLETION CODE IS ZERO.
 C
 C        FV1  AND  FV2  ARE TEMPORARY STORAGE ARRAYS.
 C
 C     QUESTIONS AND COMMENTS SHOULD BE DIRECTED TO BURTON S. GARBOW,
 C     MATHEMATICS AND COMPUTER SCIENCE DIV, ARGONNE NATIONAL LABORATORY
 C
 C     THIS VERSION DATED AUGUST 1983.
 C
 C     ------------------------------------------------------------------
 C