Program SIMPSON_COMP_5VAR
        IMPLICIT DOUBLE PRECISION (A-H,O-Z)
        DOUBLE PRECISION X5(1000000)

        a=0d0
        b=1d0
        N=10
        h=(b-a)/N


        do i=1,N
        x5(i)=a+i*h
        enddo

        sum1=0d0
        sum2=0d0
        nimp= n/2-1
        np = n/2

        do i=1,nimp
        sum1=sum1+2*g5(x5(2*i))

        enddo

        do i=1,np
        sum2=sum2+4*g5(x5(2*i-1))
        enddo

        r=h/3d0*(g5(a)+sum1+sum2+g5(b))

        open(20,File="ejerc10simp_comp_5var.xls")



        write(20,*)r
        call cpu_time(finish)
        write(20,30)finish-start
30      Format(e18.8)
        close(20)
        end


        FUNCTION  g1(x1,x2,x3,x4,x5)
        Implicit Double Precision (A-H,O-Z)
 !       parameter (a,b)

        g1=exp(-(x1*x1)-(x2*x2)-(x3*x3)-(x4*x4)-(x5*x5))*
     &   cos(x1*x2+x2*x3+x3*x4+x4*x5+x5*x1)

        END


        Function g2(x2,x3,x4,x5)
        IMPLICIT DOUBLE PRECISION (A-H,O-Z)
        DOUBLE PRECISION x1(1000000)
         N=10
         sum1=0d0
         sum2=0d0
         nimp= n/2-1
         np = n/2
         a=0d0
         b=1d0
        h=(b-a)/N


        do i=1,N
        x1(i)=a+i*h
        enddo


        do i=1,nimp
        sum1=sum1+2*g1(x1(2*i),x2,x3,x4,x5)

        enddo

        do i=1,np
        sum2=sum2+4*g1(x1(2*i-1),x2,x3,x4,x5)
        enddo

        g2=h/3d0*(g1(a,x2,x3,x4,x5)+sum1+sum2+g1(b,x2,x3,x4,x5))

        END

        Function g3(x3,x4,x5)
        IMPLICIT DOUBLE PRECISION (A-H,O-Z)
        DOUBLE PRECISION x2(1000000)
         N=10
         sum1=0d0
         sum2=0d0
         nimp= n/2-1
         np = n/2
         a=0d0
         b=1d0
        h=(b-a)/N


        do i=1,N
        x2(i)=a+i*h
        enddo


        do i=1,nimp
        sum1=sum1+2*g2(x2(2*i),x3,x4,x5)

        enddo

        do i=1,np
        sum2=sum2+4*g2(x2(2*i-1),x3,x4,x5)
        enddo

        g3=h/3d0*(g2(a,x3,x4,x5)+sum1+sum2+g2(b,x3,x4,x5))

        END
        
        Function g4(x4,x5)
        IMPLICIT DOUBLE PRECISION (A-H,O-Z)
        DOUBLE PRECISION x3(1000000)
         N=10
         sum1=0d0
         sum2=0d0
         nimp= n/2-1
         np = n/2
         a=0d0
         b=1d0
        h=(b-a)/N


        do i=1,N
        x3(i)=a+i*h
        enddo


        do i=1,nimp
        sum1=sum1+2*g3(x3(2*i),x4,x5)

        enddo

        do i=1,np
        sum2=sum2+4*g3(x3(2*i-1),x4,x5)
        enddo

        g4=h/3d0*(g3(a,x4,x5)+sum1+sum2+g3(b,x4,x5))

        END
        
        Function g5(x5)
        IMPLICIT DOUBLE PRECISION (A-H,O-Z)
        DOUBLE PRECISION x4(1000000)
         N=10
         sum1=0d0
         sum2=0d0
         nimp= n/2-1
         np = n/2
         a=0d0
         b=1d0
        h=(b-a)/N


        do i=1,N
        x4(i)=a+i*h
        enddo


        do i=1,nimp
        sum1=sum1+2*g4(x4(2*i),x5)

        enddo

        do i=1,np
        sum2=sum2+4*g4(x4(2*i-1),x5)
        enddo

        g5=h/3d0*(g4(a,x5)+sum1+sum2+g4(b,x5))

        END