RSM(3F)

NAME
     RSM, SRSM     -  EISPACK routine.  This subroutine calls the recommended
     sequence of subroutines from the eigensystem subroutine package (EISPACK)
     to find all of the eigenvalues and some of the eigenvectors of a real
     symmetric matrix.


SYNOPSYS
          subroutine  rsm(nm, n, a, w, m, z, fwork, iwork, ierr)

          integer          n, nm, m, iwork(n), ierr
          double precision a(nm,n), w(n), z(nm,m), fwork(1)      subroutine
     srsm(nm, n, a, w, m, z, fwork, iwork, ierr)

          integer          n, nm, m, iwork(n), ierr
          real             a(nm,n), w(n), z(nm,m), fwork(1)



DESCRIPTION
     ON INPUT

     NM MUST BE SET TO THE ROW DIMENSION OF THE TWO-DIMENSIONAL ARRAY
     PARAMETERS AS DECLARED IN THE CALLING PROGRAM DIMENSION STATEMENT.

     N IS THE ORDER OF THE MATRIX  A.

     A CONTAINS THE REAL SYMMETRIC MATRIX.

     M THE EIGENVECTORS CORRESPONDING TO THE FIRST M EIGENVALUES
        ARE TO BE COMPUTED.
        IF M = 0 THEN NO EIGENVECTORS ARE COMPUTED.
        IF M = N THEN ALL OF THE EIGENVECTORS ARE COMPUTED.

     ON OUTPUT

     W CONTAINS ALL N EIGENVALUES IN ASCENDING ORDER.

     Z CONTAINS THE ORTHONORMAL EIGENVECTORS ASSOCIATED WITH
        THE FIRST M EIGENVALUES.

     IERR IS AN INTEGER OUTPUT VARIABLE SET EQUAL TO AN ERROR
        COMPLETION CODE DESCRIBED IN THE DOCUMENTATION FOR TQLRAT,
        IMTQLV AND TINVIT.  THE NORMAL COMPLETION CODE IS ZERO.

     FWORK IS A TEMPORARY STORAGE ARRAY OF DIMENSION 8*N.

     IWORK IS AN INTEGER TEMPORARY STORAGE ARRAY OF DIMENSION N.

     QUESTIONS AND COMMENTS SHOULD BE DIRECTED TO BURTON S. GARBOW,
     MATHEMATICS AND COMPUTER SCIENCE DIV, ARGONNE NATIONAL LABORATORY
     THIS VERSION DATED AUGUST 1983.