paramI9I2020
C     APPENDIX E   SAMPLE PROBLEM 1
C     MATRIX ARITHEMTIC
      DIMENSION A(7,7),VECTOR(7),B(7,7)
      SENSE LIGHT 1
      DO 1 I=1,7
      DO 1 J=1,7
      B(I,J)=1./FLOATF(I+J-1)
1     A(I,J)=B(I,J)
      PRINT 13
13    FORMAT(15H1HILBERT MATRIX//)
      PRINT 2,A
2     FORMAT(1X,7E14.7)
      PRINT 15
15    FORMAT(8H0INVERSE//)
10    DO 6 K=1,7
      VECTOR=1.
      DO 3 I=2,7
3     VECTOR(I)=0.
      DO 4 J=2,8
4     A(I,J)=A(I,J)/A
      DO 5 I=1,55
5     A(I)  =A(I+1)
      DO 6 I=1,6
      A(56) =A(I,I)
      DO 6 J=1,7
6     A(I,J)=A(I,J+1)-A(56)*A(7,J)
      PRINT 2,A
      IF(SENSE LIGHT 1)11,12
11    PRINT 16
16    FORMAT(15H0MATRIX PRODUCT//)
      DO 9 K=1,7
      DO 8 I=1,7
      VECTOR(I)=0.
      DO 8 J=1,7
8     VECTOR(I)=VECTOR(I)+A(I,J)*B(J,K)
9     PRINT 18,VECTOR
18    FORMAT(1X,7F14.8)
      PRINT 17
17    FORMAT(15H0TWICE INVERTED//)
      GO TO 10
12    PRINT 7
7     FORMAT(1H1)
      STOP 111
      END
