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| program heatequation
implicit none
!Iteration variables
integer :: i
integer :: k
integer :: j
!Numerical Parameters
real, parameter :: xa=0.
real, parameter :: xb=15.
real, parameter :: dx =0.01
real, parameter :: dt=0.1
integer, parameter :: N=(xb-xa)/dx+1
real, dimension(N,N) :: A
integer, parameter :: T=50
integer :: TT
real, dimension(N) :: U0
real, dimension(N) :: U
real, dimension(N) :: V
real :: PI=3.1415926
!Initial condition
do i=1,N
U(i)=SIN((i-1)*PI*dx/xb)
end do
!Laplacian matrix
do j=1,N
do i=1,N
A(i,j)=0
end do
end do
do k=1,N-1
A(k,k)=-2
A(k+1,k)=1
A(k,k+1)=1
end do
A(N,N)=-2
!Solving PDE
TT=T/dt
do i=1,TT
U=U+dt*matmul(A,U)
end do
print*,'U at time T is equal to',U
end program heatequation |
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