17 September 2021   9:31:10.076 AM
 
FD1D_HEAT_IMPLICIT
  FORTRAN90 version
 
  Finite difference solution of
  the time dependent 1D heat equation
 
    Ut - k * Uxx = F(x,t)

  for space interval A <= X <= B with boundary conditions
 
    U(A,t) = UA(t)
    U(B,t) = UB(t)
 
  and time interval T0 <= T <= T1 with initial condition
 
    U(X,T0) = U0(X).
 
  A second order difference approximation is used for Uxx.
 
  A first order backward Euler difference approximation
  is used for Ut.
 
  X data written to "x.txt".
  T data written to "t.txt".
  U data written to "u.txt".
 
FD1D_HEAT_IMPLICIT
  Normal end of execution.

17 September 2021   9:31:10.076 AM