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eis_rt.c File Reference
#include "f2c.h"
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Functions | |
int | rt_ (integer *nm, integer *n, doublereal *a, doublereal *w, integer *matz, doublereal *z__, doublereal *fv1, integer *ierr) |
Function Documentation
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Definition at line 8 of file eis_rt.c. References a, figi2_(), figi_(), imtql1_(), and imtql2_().
00010 { 00011 /* System generated locals */ 00012 integer a_dim1, a_offset, z_dim1, z_offset; 00013 00014 /* Local variables */ 00015 extern /* Subroutine */ int figi_(integer *, integer *, doublereal *, 00016 doublereal *, doublereal *, doublereal *, integer *), figi2_( 00017 integer *, integer *, doublereal *, doublereal *, doublereal *, 00018 doublereal *, integer *), imtql1_(integer *, doublereal *, 00019 doublereal *, integer *), imtql2_(integer *, integer *, 00020 doublereal *, doublereal *, doublereal *, integer *); 00021 00022 00023 00024 /* THIS SUBROUTINE CALLS THE RECOMMENDED SEQUENCE OF */ 00025 /* SUBROUTINES FROM THE EIGENSYSTEM SUBROUTINE PACKAGE (EISPACK) */ 00026 /* TO FIND THE EIGENVALUES AND EIGENVECTORS (IF DESIRED) */ 00027 /* OF A SPECIAL REAL TRIDIAGONAL MATRIX. */ 00028 00029 /* ON INPUT */ 00030 00031 /* NM MUST BE SET TO THE ROW DIMENSION OF THE TWO-DIMENSIONAL */ 00032 /* ARRAY PARAMETERS AS DECLARED IN THE CALLING PROGRAM */ 00033 /* DIMENSION STATEMENT. */ 00034 00035 /* N IS THE ORDER OF THE MATRIX A. */ 00036 00037 /* A CONTAINS THE SPECIAL REAL TRIDIAGONAL MATRIX IN ITS */ 00038 /* FIRST THREE COLUMNS. THE SUBDIAGONAL ELEMENTS ARE STORED */ 00039 /* IN THE LAST N-1 POSITIONS OF THE FIRST COLUMN, THE */ 00040 /* DIAGONAL ELEMENTS IN THE SECOND COLUMN, AND THE SUPERDIAGONAL */ 00041 /* ELEMENTS IN THE FIRST N-1 POSITIONS OF THE THIRD COLUMN. */ 00042 /* ELEMENTS A(1,1) AND A(N,3) ARE ARBITRARY. */ 00043 00044 /* MATZ IS AN INTEGER VARIABLE SET EQUAL TO ZERO IF */ 00045 /* ONLY EIGENVALUES ARE DESIRED. OTHERWISE IT IS SET TO */ 00046 /* ANY NON-ZERO INTEGER FOR BOTH EIGENVALUES AND EIGENVECTORS. */ 00047 00048 /* ON OUTPUT */ 00049 00050 /* W CONTAINS THE EIGENVALUES IN ASCENDING ORDER. */ 00051 00052 /* Z CONTAINS THE EIGENVECTORS IF MATZ IS NOT ZERO. */ 00053 00054 /* IERR IS AN INTEGER OUTPUT VARIABLE SET EQUAL TO AN ERROR */ 00055 /* COMPLETION CODE DESCRIBED IN THE DOCUMENTATION FOR IMTQL1 */ 00056 /* AND IMTQL2. THE NORMAL COMPLETION CODE IS ZERO. */ 00057 00058 /* FV1 IS A TEMPORARY STORAGE ARRAY. */ 00059 00060 /* QUESTIONS AND COMMENTS SHOULD BE DIRECTED TO BURTON S. GARBOW, */ 00061 /* MATHEMATICS AND COMPUTER SCIENCE DIV, ARGONNE NATIONAL LABORATORY 00062 */ 00063 00064 /* THIS VERSION DATED AUGUST 1983. */ 00065 00066 /* ------------------------------------------------------------------ 00067 */ 00068 00069 /* Parameter adjustments */ 00070 a_dim1 = *nm; 00071 a_offset = a_dim1 + 1; 00072 a -= a_offset; 00073 --fv1; 00074 z_dim1 = *nm; 00075 z_offset = z_dim1 + 1; 00076 z__ -= z_offset; 00077 --w; 00078 00079 /* Function Body */ 00080 if (*n <= *nm) { 00081 goto L10; 00082 } 00083 *ierr = *n * 10; 00084 goto L50; 00085 00086 L10: 00087 if (*matz != 0) { 00088 goto L20; 00089 } 00090 /* .......... FIND EIGENVALUES ONLY .......... */ 00091 figi_(nm, n, &a[a_offset], &w[1], &fv1[1], &fv1[1], ierr); 00092 if (*ierr > 0) { 00093 goto L50; 00094 } 00095 imtql1_(n, &w[1], &fv1[1], ierr); 00096 goto L50; 00097 /* .......... FIND BOTH EIGENVALUES AND EIGENVECTORS .......... */ 00098 L20: 00099 figi2_(nm, n, &a[a_offset], &w[1], &fv1[1], &z__[z_offset], ierr); 00100 if (*ierr != 0) { 00101 goto L50; 00102 } 00103 imtql2_(nm, n, &w[1], &fv1[1], &z__[z_offset], ierr); 00104 L50: 00105 return 0; 00106 } /* rt_ */ |