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eis_rsgba.c File Reference
#include "f2c.h"
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Functions | |
int | rsgba_ (integer *nm, integer *n, doublereal *a, doublereal *b, 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_rsgba.c. References a, rebakb_(), reduc2_(), tql2_(), tqlrat_(), tred1_(), and tred2_().
00011 { 00012 /* System generated locals */ 00013 integer a_dim1, a_offset, b_dim1, b_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 , reduc2_(integer *, integer *, doublereal *, doublereal *, 00020 doublereal *, integer *), rebakb_(integer *, integer *, 00021 doublereal *, doublereal *, integer *, doublereal *), tqlrat_( 00022 integer *, doublereal *, doublereal *, integer *), tql2_(integer * 00023 , integer *, doublereal *, doublereal *, doublereal *, integer *); 00024 00025 00026 00027 /* THIS SUBROUTINE CALLS THE RECOMMENDED SEQUENCE OF */ 00028 /* SUBROUTINES FROM THE EIGENSYSTEM SUBROUTINE PACKAGE (EISPACK) */ 00029 /* TO FIND THE EIGENVALUES AND EIGENVECTORS (IF DESIRED) */ 00030 /* FOR THE REAL SYMMETRIC GENERALIZED EIGENPROBLEM BAX = (LAMBDA)X. 00031 */ 00032 00033 /* ON INPUT */ 00034 00035 /* NM MUST BE SET TO THE ROW DIMENSION OF THE TWO-DIMENSIONAL */ 00036 /* ARRAY PARAMETERS AS DECLARED IN THE CALLING PROGRAM */ 00037 /* DIMENSION STATEMENT. */ 00038 00039 /* N IS THE ORDER OF THE MATRICES A AND B. */ 00040 00041 /* A CONTAINS A REAL SYMMETRIC MATRIX. */ 00042 00043 /* B CONTAINS A POSITIVE DEFINITE REAL SYMMETRIC MATRIX. */ 00044 00045 /* MATZ IS AN INTEGER VARIABLE SET EQUAL TO ZERO IF */ 00046 /* ONLY EIGENVALUES ARE DESIRED. OTHERWISE IT IS SET TO */ 00047 /* ANY NON-ZERO INTEGER FOR BOTH EIGENVALUES AND EIGENVECTORS. */ 00048 00049 /* ON OUTPUT */ 00050 00051 /* W CONTAINS THE EIGENVALUES IN ASCENDING ORDER. */ 00052 00053 /* Z CONTAINS THE EIGENVECTORS IF MATZ IS NOT ZERO. */ 00054 00055 /* IERR IS AN INTEGER OUTPUT VARIABLE SET EQUAL TO AN ERROR */ 00056 /* COMPLETION CODE DESCRIBED IN THE DOCUMENTATION FOR TQLRAT */ 00057 /* AND TQL2. THE NORMAL COMPLETION CODE IS ZERO. */ 00058 00059 /* FV1 AND FV2 ARE TEMPORARY STORAGE ARRAYS. */ 00060 00061 /* QUESTIONS AND COMMENTS SHOULD BE DIRECTED TO BURTON S. GARBOW, */ 00062 /* MATHEMATICS AND COMPUTER SCIENCE DIV, ARGONNE NATIONAL LABORATORY 00063 */ 00064 00065 /* THIS VERSION DATED AUGUST 1983. */ 00066 00067 /* ------------------------------------------------------------------ 00068 */ 00069 00070 /* Parameter adjustments */ 00071 --fv2; 00072 --fv1; 00073 z_dim1 = *nm; 00074 z_offset = z_dim1 + 1; 00075 z__ -= z_offset; 00076 --w; 00077 b_dim1 = *nm; 00078 b_offset = b_dim1 + 1; 00079 b -= b_offset; 00080 a_dim1 = *nm; 00081 a_offset = a_dim1 + 1; 00082 a -= a_offset; 00083 00084 /* Function Body */ 00085 if (*n <= *nm) { 00086 goto L10; 00087 } 00088 *ierr = *n * 10; 00089 goto L50; 00090 00091 L10: 00092 reduc2_(nm, n, &a[a_offset], &b[b_offset], &fv2[1], ierr); 00093 if (*ierr != 0) { 00094 goto L50; 00095 } 00096 if (*matz != 0) { 00097 goto L20; 00098 } 00099 /* .......... FIND EIGENVALUES ONLY .......... */ 00100 tred1_(nm, n, &a[a_offset], &w[1], &fv1[1], &fv2[1]); 00101 tqlrat_(n, &w[1], &fv2[1], ierr); 00102 goto L50; 00103 /* .......... FIND BOTH EIGENVALUES AND EIGENVECTORS .......... */ 00104 L20: 00105 tred2_(nm, n, &a[a_offset], &w[1], &fv1[1], &z__[z_offset]); 00106 tql2_(nm, n, &w[1], &fv1[1], &z__[z_offset], ierr); 00107 if (*ierr != 0) { 00108 goto L50; 00109 } 00110 rebakb_(nm, n, &b[b_offset], &fv2[1], n, &z__[z_offset]); 00111 L50: 00112 return 0; 00113 } /* rsgba_ */ |