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RSB(NM,N,MB,A,W,MATZ,Z,FV1,FV2,IERR)

       SUBROUTINE RSB(NM,N,MB,A,W,MATZ,Z,FV1,FV2,IERR)
 C
       INTEGER N,MB,NM,IERR,MATZ
       REAL A(NM,MB),W(N),Z(NM,N),FV1(N),FV2(N)
       LOGICAL TF
 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     OF A REAL SYMMETRIC BAND MATRIX.
 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 MATRIX  A.
 C
 C        MB  IS THE HALF BAND WIDTH OF THE MATRIX, DEFINED AS THE
 C        NUMBER OF ADJACENT DIAGONALS, INCLUDING THE PRINCIPAL
 C        DIAGONAL, REQUIRED TO SPECIFY THE NON-ZERO PORTION OF THE
 C        LOWER TRIANGLE OF THE MATRIX.
 C
 C        A  CONTAINS THE LOWER TRIANGLE OF THE REAL SYMMETRIC
 C        BAND MATRIX.  ITS LOWEST SUBDIAGONAL IS STORED IN THE
 C        LAST  N+1-MB  POSITIONS OF THE FIRST COLUMN, ITS NEXT
 C        SUBDIAGONAL IN THE LAST  N+2-MB  POSITIONS OF THE
 C        SECOND COLUMN, FURTHER SUBDIAGONALS SIMILARLY, AND
 C        FINALLY ITS PRINCIPAL DIAGONAL IN THE  N  POSITIONS
 C        OF THE LAST COLUMN.  CONTENTS OF STORAGES NOT PART
 C        OF THE MATRIX ARE ARBITRARY.
 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