source/unres/src_MD/banach.f

   1 C
   2 C**********************
   3       SUBROUTINE BANACH(N,NMAX,A,X,osob)
   4 C**********************
   5 C     Banachiewicz
   6       implicit real*8 (a-h,o-z)
   7       include 'DIMENSIONS'
   8       DIMENSION A(NMAX,NMAX),X(NMAX),D(MAXRES6)
   9       COMMON /BANII/ D
  10       logical osob
  11       osob=.false.
  12       if (dabs(a(1,1)).lt.1.0d-15) then
  13         osob=.true.
  14         return
  15       endif
  16       D(1)=1./A(1,1)
  17       DO 80 I=2,N
  18       A(I,1)=A(1,I)
  19       DO 81 J=2,I-1
  20       XX=A(J,I)
  21       DO 82 K=1,J-1
  22       XX=XX-A(I,K)*A(J,K)
  23    82 CONTINUE
  24       A(I,J)=XX
  25    81 CONTINUE
  26       XX=A(I,I)
  27       JJJJ=I-1
  28       DO 83 J=1,JJJJ
  29       AIJ=A(I,J)
  30       AIJD=AIJ*D(J)
  31       A(I,J)=AIJD
  32       XX=XX-AIJ*AIJD
  33    83 CONTINUE
  34       if (dabs(xx).lt.1.0d-15) then
  35         osob=.true.
  36         return
  37       endif
  38       D(I)=1./XX
  39    80 CONTINUE
  40 C
  41       CALL BANAII(N,NMAX,A,X)
  42       RETURN
  43       END
  44 C************************
  45       SUBROUTINE BANAII(N,NMAX,A,X)
  46 C************************
  47       implicit real*8 (a-h,o-z)
  48       include 'DIMENSIONS'
  49       DIMENSION A(NMAX,NMAX),X(NMAX),D(MAXRES6)
  50       COMMON /BANII/ D
  51       DO 90 I=1,N
  52       Z=X(I)
  53       JJJJ=I-1
  54       DO 91 J=JJJJ,1,-1
  55       Z=Z-A(I,J)*X(J)
  56    91 CONTINUE
  57       X(I)=Z
  58    90 CONTINUE
  59       DO 92 I=N,1,-1
  60       Z=X(I)*D(I)
  61       JJJJ=I+1
  62       DO 93 J=JJJJ,N
  63       Z=Z-A(J,I)*X(J)
  64    93 CONTINUE
  65       X(I)=Z
  66    92 CONTINUE
  67       RETURN
  68       END
  69 C
  70       SUBROUTINE MATINVERT(N,NMAX,A,A1,osob)
  71       implicit real*8 (a-h,o-z)
  72       include 'DIMENSIONS'
  73       DIMENSION A(NMAX,NMAX),A1(NMAX,NMAX),D(MAXRES6)
  74       COMMON /BANII/ D
  75       DIMENSION X(NMAX)
  76       logical osob
  77       DO I=1,N
  78         X(I)=0.0
  79       ENDDO
  80       X(1)=1.0
  81       CALL BANACH(N,NMAX,A,X,osob)
  82       if (osob) return
  83       DO I=1,N
  84         A1(I,1)=X(I)
  85       ENDDO
  86       DO I=2,N
  87         DO J=1,N
  88           X(J)=0.0
  89         ENDDO
  90         X(I)=1.0
  91         CALL BANAII(N,NMAX,A,X)
  92         DO J=1,N
  93           A1(J,I)=X(J)
  94         ENDDO
  95       ENDDO
  96       RETURN
  97       END
  98
  99