00001 /* rst.f -- translated by f2c (version 19961017).
00002    You must link the resulting object file with the libraries:
00003         -lf2c -lm   (in that order)
00004 */
00005 
00006 #include "f2c.h"
00007 
00008 /* Subroutine */ int rst_(integer *nm, integer *n, doublereal *w, doublereal *
00009         e, integer *matz, doublereal *z__, integer *ierr)
00010 {
00011     /* System generated locals */
00012     integer z_dim1, z_offset, i__1, i__2;
00013 
00014     /* Local variables */
00015     static integer i__, j;
00016     extern /* Subroutine */ int imtql1_(integer *, doublereal *, doublereal *,
00017              integer *), imtql2_(integer *, integer *, doublereal *, 
00018             doublereal *, doublereal *, integer *);
00019 
00020 
00021 
00022 /*     THIS SUBROUTINE CALLS THE RECOMMENDED SEQUENCE OF */
00023 /*     SUBROUTINES FROM THE EIGENSYSTEM SUBROUTINE PACKAGE (EISPACK) */
00024 /*     TO FIND THE EIGENVALUES AND EIGENVECTORS (IF DESIRED) */
00025 /*     OF A REAL SYMMETRIC TRIDIAGONAL MATRIX. */
00026 
00027 /*     ON INPUT */
00028 
00029 /*        NM  MUST BE SET TO THE ROW DIMENSION OF THE TWO-DIMENSIONAL */
00030 /*        ARRAY PARAMETERS AS DECLARED IN THE CALLING PROGRAM */
00031 /*        DIMENSION STATEMENT. */
00032 
00033 /*        N  IS THE ORDER OF THE MATRIX. */
00034 
00035 /*        W  CONTAINS THE DIAGONAL ELEMENTS OF THE REAL */
00036 /*        SYMMETRIC TRIDIAGONAL MATRIX. */
00037 
00038 /*        E  CONTAINS THE SUBDIAGONAL ELEMENTS OF THE MATRIX IN */
00039 /*        ITS LAST N-1 POSITIONS.  E(1) IS ARBITRARY. */
00040 
00041 /*        MATZ  IS AN INTEGER VARIABLE SET EQUAL TO ZERO IF */
00042 /*        ONLY EIGENVALUES ARE DESIRED.  OTHERWISE IT IS SET TO */
00043 /*        ANY NON-ZERO INTEGER FOR BOTH EIGENVALUES AND EIGENVECTORS. */
00044 
00045 /*     ON OUTPUT */
00046 
00047 /*        W  CONTAINS THE EIGENVALUES IN ASCENDING ORDER. */
00048 
00049 /*        Z  CONTAINS THE EIGENVECTORS IF MATZ IS NOT ZERO. */
00050 
00051 /*        IERR  IS AN INTEGER OUTPUT VARIABLE SET EQUAL TO AN ERROR */
00052 /*           COMPLETION CODE DESCRIBED IN THE DOCUMENTATION FOR IMTQL1 */
00053 /*           AND IMTQL2.  THE NORMAL COMPLETION CODE IS ZERO. */
00054 
00055 /*     QUESTIONS AND COMMENTS SHOULD BE DIRECTED TO BURTON S. GARBOW, */
00056 /*     MATHEMATICS AND COMPUTER SCIENCE DIV, ARGONNE NATIONAL LABORATORY 
00057 */
00058 
00059 /*     THIS VERSION DATED AUGUST 1983. */
00060 
00061 /*     ------------------------------------------------------------------ 
00062 */
00063 
00064     /* Parameter adjustments */
00065     z_dim1 = *nm;
00066     z_offset = z_dim1 + 1;
00067     z__ -= z_offset;
00068     --e;
00069     --w;
00070 
00071     /* Function Body */
00072     if (*n <= *nm) {
00073         goto L10;
00074     }
00075     *ierr = *n * 10;
00076     goto L50;
00077 
00078 L10:
00079     if (*matz != 0) {
00080         goto L20;
00081     }
00082 /*     .......... FIND EIGENVALUES ONLY .......... */
00083     imtql1_(n, &w[1], &e[1], ierr);
00084     goto L50;
00085 /*     .......... FIND BOTH EIGENVALUES AND EIGENVECTORS .......... */
00086 L20:
00087     i__1 = *n;
00088     for (i__ = 1; i__ <= i__1; ++i__) {
00089 
00090         i__2 = *n;
00091         for (j = 1; j <= i__2; ++j) {
00092             z__[j + i__ * z_dim1] = 0.;
00093 /* L30: */
00094         }
00095 
00096         z__[i__ + i__ * z_dim1] = 1.;
00097 /* L40: */
00098     }
00099 
00100     imtql2_(nm, n, &w[1], &e[1], &z__[z_offset], ierr);
00101 L50:
00102     return 0;
00103 } /* rst_ */
00104