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eis_rs.c File Reference
#include "f2c.h"
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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_ */ |