5 * Revision 1.1.1.1 1996/02/15 17:48:48 mclareni
9 #include "kernnum/pilot.h"
10 SUBROUTINE DEQINV(N,A,IDIM,R,IFAIL,K,B)
12 DOUBLE PRECISION A(IDIM,N),B(IDIM,K),DET,TEMP,S,
13 $ B1,B2,C11,C12,C13,C21,C22,C23,C31,C32,C33
15 DATA NAME/'DEQINV'/,KPRNT/1/
17 C ******************************************************************
19 C REPLACES B BY THE SOLUTION X OF A*X=B, AND REPLACES A BY ITS IN-
22 C N ORDER OF THE SQUARE MATRIX IN ARRAY A.
24 C A (DOUBLE PRECISION) TWO-DIMENSIONAL ARRAY CONTAINING
27 C IDIM FIRST DIMENSION PARAMETER OF ARRAYS A AND B.
29 C R (REAL) WORKING VECTOR OF LENGTH NOT LESS THAN N.
31 C IFAIL OUTPUT PARAMETER. IFAIL= 0 ... NORMAL EXIT.
32 C IFAIL=-1 ... SINGULAR MATRIX.
34 C K NUMBER OF COLUMNS OF THE MATRIX IN ARRAY B.
36 C B (DOUBLE PRECISION) TWO-DIMENSIONAL ARRAY CONTAINING
39 C CALLS ... DFACT, DFINV, F010PR, ABEND.
41 C ******************************************************************
43 C TEST FOR PARAMETER ERRORS.
45 IF((N.LT.1).OR.(N.GT.IDIM).OR.(K.LT.1)) GO TO 10
56 C11=A(2,2)*A(3,3)-A(2,3)*A(3,2)
57 C12=A(2,3)*A(3,1)-A(2,1)*A(3,3)
58 C13=A(2,1)*A(3,2)-A(2,2)*A(3,1)
59 C21=A(3,2)*A(1,3)-A(3,3)*A(1,2)
60 C22=A(3,3)*A(1,1)-A(3,1)*A(1,3)
61 C23=A(3,1)*A(1,2)-A(3,2)*A(1,1)
62 C31=A(1,2)*A(2,3)-A(1,3)*A(2,2)
63 C32=A(1,3)*A(2,1)-A(1,1)*A(2,3)
64 C33=A(1,1)*A(2,2)-A(1,2)*A(2,1)
69 C (SET TEMP=PIVOT AND DET=PIVOT*DET.)
76 1 IF(T3.GE.T1) GO TO 2
85 C SET ELEMENTS OF INVERSE IN A.
86 3 IF(DET.EQ.0D0) GO TO 11
98 C REPLACE B BY AINV*B.
102 B(1,J)=A(1,1)*B1+A(1,2)*B2+A(1,3)*B(3,J)
103 B(2,J)=A(2,1)*B1+A(2,2)*B2+A(2,3)*B(3,J)
104 B(3,J)=A(3,1)*B1+A(3,2)*B2+A(3,3)*B(3,J)
110 C N=2 CASE BY CRAMERS RULE.
112 DET=A(1,1)*A(2,2)-A(1,2)*A(2,1)
113 IF(DET.EQ.0D0) GO TO 11
122 B(1,J)=C11*B1+A(1,2)*B(2,J)
123 B(2,J)=A(2,1)*B1+A(2,2)*B(2,J)
129 7 IF(A(1,1).EQ.0D0) GO TO 11
136 C N.GT.3 CASES. FACTORIZE MATRIX, INVERT AND SOLVE SYSTEM.
138 9 CALL DFACT(N,A,IDIM,R,IFAIL,DET,JFAIL)
139 IF(IFAIL.NE.0) RETURN
140 CALL DFEQN(N,A,IDIM,R,K,B)
141 CALL DFINV(N,A,IDIM,R)
147 CALL F010PR(NAME,N,IDIM,K,KPRNT)