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±¾ÈËÓÃfortran·´ÃÝ·¨Çó½â×îСÌØÕ÷Öµ£¬ÆäÖÐÇó½âÏßÐÔ·½³Ì×éµÄ²¿·ÖÓÉÓÚÊÇ´ø×´Õó£¬Òò´Ë²ÉÓÃÁËѹËõ¿Õ¼äµÄ´æ´¢·½Ê½C£¨m,n£© µ«ÊÇ×Ó³ÌÐòµ¥¶Àµ÷ÊÔ¶¼ÄÜͨ¹ý£¬·ÅÔÚÒ»Æð¾ÍÓÐÎÊÌâÁË£¬ÄÄλ´óÉñ°ïæ¿´¿´ program homework implicit none !¶¨Òå Integer , parameter :: p = SELECTED_REAL_KIND(8)   real(p) ::        a(501),db=0.16,dc=-0.064,mc(5,501) real(p)    :: Rs integer :: i,n=501,m=5 !a³õʼ»¯ do i=1,n a(i)=(1.64-0.024*i)*sin(0.2*i)-0.64*exp(0.1/i) end do !¸øC¸³³õÖµ5*501 mc(1,=dc mc(2,=db do i=1,n mc(3,i)=a(i) end do mc(4,=db mc(5,=dc mc(1,1)=0.0 mc(1,2)=0.0 mc(2,1)=0.0 mc(5,n)=0.0 mc(4,n)=0.0 mc(5,n-1)=0.0 !ÇóRs(¼´°´Ä£×îСµÄÌØÕ÷Öµ)£¬·´ÃÝ·¨ call InPowoe(mc,m,n,Rs) write(*,*) write(*,*) "Rs===============",Rs end program homework !***************************************************** !×Ó³ÌÐò·´ÃÝ·¨ÇóÌØÕ÷Öµ(Inverse power of eigenvalue)         * !***************************************************** subroutine InPowoe(c,m,n,r) implicit none Integer , parameter :: p = SELECTED_REAL_KIND(8) integer :: m,n real(p) :: r,c(m,n) real(p) :: u(n),y(n),t,max,flag real(p) :: sum integer :: i sum=0.0 max=1.0 flag=1.0 u(1)=1.0 do i=2,n u(i)=1.0 end do !¼ÆËã do while(flag>=0.00001)   do i=1,n     sum=sum+u(i)*u(i)   end do    t=sqrt(sum)    sum=0.0   do i=1,n     y(i)=u(i)/t   end do   !A*u=y,Çó½â´ø×´ÏßÐÔ·½³Ì×é    call LU(c,u,y,m,n)   !ÌØÕ÷Öµ   do i=1,n     sum=sum+y(i)*u(i)   end do     r=sum         sum=0.0   !½áÊøÅÐ¶Ï   flag=abs(r-max)/abs(r)   max=r end do r=1.0/r end subroutine         InPowoe subroutine LU(a,x,b,m,n) implicit none Integer , parameter :: p = SELECTED_REAL_KIND(8) integer :: i,j,k,r,s,t,m,n real(p) :: a(m,n),x(n),b(n),c(m,n) real(p) :: sum sum=0.0 r=2 s=2 do i=1,m   c(i,=a(i, end do !·Ö½â do k=1,n   do j=k,min(k+s,n)     do t=max(1,k-r,j-s),k-1           sum=sum+c(k-t+s+1,t)*c(t-j+s+1,j)         end do         c(k-j+s+1,j)=c(k-j+s+1,j)-sum         sum=0.0   end do      if(k<n) then   do i=k+1,min(k+r,n)     do t=max(1,i-r,k-s),k-1           sum=sum+c(i-t+s+1,t)*c(t-k+s+1,k)         end do         c(i-k+s+1,k)=(c(i-k+s+1,k)-sum)/c(s+1,k)         sum=0.0   end do   end if end do !Çó½â do i=2,n   do t=max(1,i-r),i-1      sum=sum+c(i-t+s+1,t)*b(t)     end do   b(i)=b(i)-sum   sum=0.0 end do x(n)=b(n)/c(s+1,n) do i=n-1,1,-1    do t=i+1,min(i+s,n)       sum=sum+c(i-t+s+1,t)*x(t)    end do    x(i)=(b(i)-sum)/c(s+1,i)    sum=0.0 end do end subroutine LU

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