2-96_Monte Carlo.F95

PROGRAM QQQ2
IMPLICIT NONE
DOUBLE PRECISION :: R1, R2
DOUBLE PRECISION, PARAMETER :: UX = 3 .0, LX = -1 .0
DOUBLE PRECISION, PARAMETER :: UY = 2 .0, LY = 0 .0
DOUBLE PRECISION :: SUMMATION
DOUBLE PRECISION :: ANSWER
DOUBLE PRECISION :: FUNNY
INTEGER :: I
INTEGER, PARAMETER :: N = 10000
! ---------------------
CALL RANDOM_SEED()
! ---------------------
SUMMATION = 0 .0
DO I=1, N
CALL RANDOM_NUMBER( R1)
CALL RANDOM_NUMBER( R2)
R1 = (UX - LX)* R1 + LX
R2 = (UY - LY)* R2 + LY
SUMMATION = SUMMATION + FUNNY( R1, R2)
END DO
ANSWER = (UX-LX)*(UY-LY)*SUMMATION/(N*1 .0)
WRITE(*,*) "ANSWER = ", ANSWER
STOP
END PROGRAM QQQ2
FUNCTION FUNNY(X,Y)
IMPLICIT NONE
DOUBLE PRECISION :: X, Y, FUNNY
FUNNY = X*Y + ABS(Y)**(X) + ABS(X)**Y + X/(1 .0+ABS(Y))
END FUNCTION FUNNY