Doxygen Source Code Documentation
eis_rs.c File Reference
#include "f2c.h"Go to the source code of this file.
Functions | |
| int | rs_ (integer *nm, integer *n, doublereal *a, doublereal *w, integer *matz, doublereal *z__, doublereal *fv1, doublereal *fv2, integer *ierr) |
Function Documentation
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Definition at line 8 of file eis_rs.c. References a, tql2_(), tqlrat_(), tred1_(), and tred2_(). Referenced by symeig_double(), and symeigval_double().
00011 {
00012 /* System generated locals */
00013 integer a_dim1, a_offset, z_dim1, z_offset;
00014
00015 /* Local variables */
00016 extern /* Subroutine */ int tred1_(integer *, integer *, doublereal *,
00017 doublereal *, doublereal *, doublereal *), tred2_(integer *,
00018 integer *, doublereal *, doublereal *, doublereal *, doublereal *)
00019 , tqlrat_(integer *, doublereal *, doublereal *, integer *),
00020 tql2_(integer *, integer *, doublereal *, doublereal *,
00021 doublereal *, integer *);
00022
00023
00024
00025 /* THIS SUBROUTINE CALLS THE RECOMMENDED SEQUENCE OF */
00026 /* SUBROUTINES FROM THE EIGENSYSTEM SUBROUTINE PACKAGE (EISPACK) */
00027 /* TO FIND THE EIGENVALUES AND EIGENVECTORS (IF DESIRED) */
00028 /* OF A REAL SYMMETRIC MATRIX. */
00029
00030 /* ON INPUT */
00031
00032 /* NM MUST BE SET TO THE ROW DIMENSION OF THE TWO-DIMENSIONAL */
00033 /* ARRAY PARAMETERS AS DECLARED IN THE CALLING PROGRAM */
00034 /* DIMENSION STATEMENT. */
00035
00036 /* N IS THE ORDER OF THE MATRIX A. */
00037
00038 /* A CONTAINS THE REAL SYMMETRIC MATRIX. */
00039
00040 /* MATZ IS AN INTEGER VARIABLE SET EQUAL TO ZERO IF */
00041 /* ONLY EIGENVALUES ARE DESIRED. OTHERWISE IT IS SET TO */
00042 /* ANY NON-ZERO INTEGER FOR BOTH EIGENVALUES AND EIGENVECTORS. */
00043
00044 /* ON OUTPUT */
00045
00046 /* W CONTAINS THE EIGENVALUES IN ASCENDING ORDER. */
00047
00048 /* Z CONTAINS THE EIGENVECTORS IF MATZ IS NOT ZERO. */
00049
00050 /* IERR IS AN INTEGER OUTPUT VARIABLE SET EQUAL TO AN ERROR */
00051 /* COMPLETION CODE DESCRIBED IN THE DOCUMENTATION FOR TQLRAT */
00052 /* AND TQL2. THE NORMAL COMPLETION CODE IS ZERO. */
00053
00054 /* FV1 AND FV2 ARE TEMPORARY STORAGE ARRAYS. */
00055
00056 /* QUESTIONS AND COMMENTS SHOULD BE DIRECTED TO BURTON S. GARBOW, */
00057 /* MATHEMATICS AND COMPUTER SCIENCE DIV, ARGONNE NATIONAL LABORATORY
00058 */
00059
00060 /* THIS VERSION DATED AUGUST 1983. */
00061
00062 /* ------------------------------------------------------------------
00063 */
00064
00065 /* Parameter adjustments */
00066 --fv2;
00067 --fv1;
00068 z_dim1 = *nm;
00069 z_offset = z_dim1 + 1;
00070 z__ -= z_offset;
00071 --w;
00072 a_dim1 = *nm;
00073 a_offset = a_dim1 + 1;
00074 a -= a_offset;
00075
00076 /* Function Body */
00077 if (*n <= *nm) {
00078 goto L10;
00079 }
00080 *ierr = *n * 10;
00081 goto L50;
00082
00083 L10:
00084 if (*matz != 0) {
00085 goto L20;
00086 }
00087 /* .......... FIND EIGENVALUES ONLY .......... */
00088 tred1_(nm, n, &a[a_offset], &w[1], &fv1[1], &fv2[1]);
00089 tqlrat_(n, &w[1], &fv2[1], ierr);
00090 goto L50;
00091 /* .......... FIND BOTH EIGENVALUES AND EIGENVECTORS .......... */
00092 L20:
00093 tred2_(nm, n, &a[a_offset], &w[1], &fv1[1], &z__[z_offset]);
00094 tql2_(nm, n, &w[1], &fv1[1], &z__[z_offset], ierr);
00095 L50:
00096 return 0;
00097 } /* rs_ */
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