程序The explicit heat-flow equation

sillybear

# Explicit heat-flow equation
real q(12), qp(12)
nx = 12
do ia= 1, 2 {# stable and unstable cases
alpha = ia*.3333;write(6,'(/"alpha =",f5.2)') alpha
do ix= 1,6  { q(ix) = 0.}# Initial temperature step
do ix= 7,12 { q(ix) = 1.}
do it= 1, 6 {
write(6,'(20f6.2)') (q(ix),ix=1,nx)
do ix= 2, nx-1
qp(ix) = q(ix) + alpha*(q(ix-1)-2.*q(ix)+q(ix+1))
qp(1) = qp(2);qp(nx) = qp(nx-1)
do ix= 1, nx
q(ix) = qp(ix)
}
}
call exit(0);end

sillybear

http://sepwww.stanford.edu/sep/prof/iei/omx/paper_html/node17.html#SECTION00124000000000000000
The heat-flow equation controls the diffusion of heat. This equation is a prototype for migration. The 15 migration equation is the same equation but the heat conductivity constant is imaginary. (The migration equation is really the Schroedinger equation, which controls the diffusion of probability of atomic particles).