由於某種原因,它永遠不會插值,但它將0作爲答案。代碼是:爲什麼我的拉格朗日插值算法不起作用?
PROGRAM LAGRANGE
REAL X(0:100), Y(0:100), INTERP
REAL TEMP = 1.0
REAL POLINOM = 0.0
N=10
OPEN(1,FILE="datos.txt")
DO I=0,100 !We 'clean' the arrays: all positions are 0
X(I)=0.0
Y(I)=0.0
END DO
DO I=0,10 !We read the data file and we save the info
READ(1,*) X(I), Y(I)
END DO
CLOSE(1)
WRITE(*,*) "Data table:"
DO I=0,10
WRITE(*,*) X(I), Y(I)
END DO
WRITE(*,*) "Which value of X do you want to interpolate?"
READ(*,*) INTERP
DO I=0,N
DO J=0,N
IF(J.NE.I) THEN !Condition: J and I can't be equal
TEMP=TEMP*(INTERP-X(J))/(X(I)-X(J))
ELSE IF(J==I) THEN
TEMP=TEMP*1.0
ELSE
END IF
END DO
POLINOM=POLINOM+TEMP
END DO
WRITE(*,*) "Value: ",POLINOM
STOP
END PROGRAM
我在哪裏失敗?基本上,我需要實現這個:
非常感謝提前。