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SUBROUTINE RST(NM,N,W,E,MATZ,Z,IERR) C INTEGER I,J,N,NM,IERR,MATZ DOUBLE PRECISION W(N),E(N),Z(NM,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 OF A REAL SYMMETRIC TRIDIAGONAL 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. C C W CONTAINS THE DIAGONAL ELEMENTS OF THE REAL C SYMMETRIC TRIDIAGONAL MATRIX. C C E CONTAINS THE SUBDIAGONAL ELEMENTS OF THE MATRIX IN C ITS LAST N-1 POSITIONS. E(1) IS 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 IMTQL1 C AND IMTQL2. THE NORMAL COMPLETION CODE IS ZERO. 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