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Last change
on this file since 2768 was
524,
checked in by lmdzadmin, 21 years ago
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Initial revision
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Property svn:eol-style set to
native
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Property svn:keywords set to
Author Date Id Revision
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File size:
2.5 KB
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| 1 | ! |
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| 2 | ! $Header$ |
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| 3 | ! |
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| 4 | SUBROUTINE JACOBI(A,N,NP,D,V,NROT) |
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| 5 | PARAMETER (NMAX=400) |
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| 6 | DIMENSION A(NP,NP),D(NP),V(NP,NP),B(NMAX),Z(NMAX) |
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| 7 | IF (n.gt.nmax) THEN |
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| 8 | print*, 'n, nmax=', n, nmax |
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| 9 | print*, 'Surdimensionnement insuffisant dans jacobi' |
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| 10 | CALL abort |
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| 11 | ENDIF |
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| 12 | DO 12 IP=1,N |
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| 13 | DO 11 IQ=1,N |
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| 14 | V(IP,IQ)=0. |
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| 15 | 11 CONTINUE |
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| 16 | V(IP,IP)=1. |
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| 17 | 12 CONTINUE |
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| 18 | DO 13 IP=1,N |
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| 19 | B(IP)=A(IP,IP) |
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| 20 | D(IP)=B(IP) |
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| 21 | Z(IP)=0. |
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| 22 | 13 CONTINUE |
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| 23 | NROT=0 |
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| 24 | DO 24 I=1,50 |
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| 25 | SM=0. |
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| 26 | DO 15 IP=1,N-1 |
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| 27 | DO 14 IQ=IP+1,N |
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| 28 | SM=SM+ABS(A(IP,IQ)) |
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| 29 | 14 CONTINUE |
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| 30 | 15 CONTINUE |
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| 31 | IF(SM.EQ.0.)RETURN |
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| 32 | IF(I.LT.4)THEN |
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| 33 | TRESH=0.2*SM/N**2 |
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| 34 | ELSE |
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| 35 | TRESH=0. |
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| 36 | ENDIF |
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| 37 | DO 22 IP=1,N-1 |
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| 38 | DO 21 IQ=IP+1,N |
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| 39 | G=100.*ABS(A(IP,IQ)) |
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| 40 | IF((I.GT.4).AND.(ABS(D(IP))+G.EQ.ABS(D(IP))) |
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| 41 | * .AND.(ABS(D(IQ))+G.EQ.ABS(D(IQ))))THEN |
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| 42 | A(IP,IQ)=0. |
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| 43 | ELSE IF(ABS(A(IP,IQ)).GT.TRESH)THEN |
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| 44 | H=D(IQ)-D(IP) |
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| 45 | IF(ABS(H)+G.EQ.ABS(H))THEN |
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| 46 | T=A(IP,IQ)/H |
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| 47 | ELSE |
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| 48 | THETA=0.5*H/A(IP,IQ) |
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| 49 | T=1./(ABS(THETA)+SQRT(1.+THETA**2)) |
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| 50 | IF(THETA.LT.0.)T=-T |
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| 51 | ENDIF |
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| 52 | C=1./SQRT(1+T**2) |
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| 53 | S=T*C |
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| 54 | TAU=S/(1.+C) |
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| 55 | H=T*A(IP,IQ) |
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| 56 | Z(IP)=Z(IP)-H |
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| 57 | Z(IQ)=Z(IQ)+H |
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| 58 | D(IP)=D(IP)-H |
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| 59 | D(IQ)=D(IQ)+H |
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| 60 | A(IP,IQ)=0. |
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| 61 | DO 16 J=1,IP-1 |
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| 62 | G=A(J,IP) |
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| 63 | H=A(J,IQ) |
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| 64 | A(J,IP)=G-S*(H+G*TAU) |
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| 65 | A(J,IQ)=H+S*(G-H*TAU) |
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| 66 | 16 CONTINUE |
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| 67 | DO 17 J=IP+1,IQ-1 |
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| 68 | G=A(IP,J) |
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| 69 | H=A(J,IQ) |
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| 70 | A(IP,J)=G-S*(H+G*TAU) |
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| 71 | A(J,IQ)=H+S*(G-H*TAU) |
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| 72 | 17 CONTINUE |
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| 73 | DO 18 J=IQ+1,N |
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| 74 | G=A(IP,J) |
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| 75 | H=A(IQ,J) |
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| 76 | A(IP,J)=G-S*(H+G*TAU) |
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| 77 | A(IQ,J)=H+S*(G-H*TAU) |
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| 78 | 18 CONTINUE |
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| 79 | DO 19 J=1,N |
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| 80 | G=V(J,IP) |
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| 81 | H=V(J,IQ) |
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| 82 | V(J,IP)=G-S*(H+G*TAU) |
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| 83 | V(J,IQ)=H+S*(G-H*TAU) |
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| 84 | 19 CONTINUE |
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| 85 | NROT=NROT+1 |
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| 86 | ENDIF |
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| 87 | 21 CONTINUE |
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| 88 | 22 CONTINUE |
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| 89 | DO 23 IP=1,N |
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| 90 | B(IP)=B(IP)+Z(IP) |
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| 91 | D(IP)=B(IP) |
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| 92 | Z(IP)=0. |
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| 93 | 23 CONTINUE |
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| 94 | 24 CONTINUE |
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| 95 | STOP '50 iterations should never happen' |
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| 96 | RETURN |
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| 97 | END |
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