I want to solve the following 1-D pde which is discretized in spacial direction to solve using ode15s.
Dc/Dt = D*D^c/Dx^2 - v*Dc/Dx.
With initial condition,
c(x,0) = Co
Boundary conditions ,
Dirichlet boundary condition at left boundary,
c(0,t) = cl;
Neumann boundary condition at right boundary,
dc/dx = 0;
I'm not very clear about defining the mass matrix for the input options in the call to ode15s
options = odeset('Mass',M,'RelTol',1e-4,'AbsTol',[1e-6 1e-10 1e-6]);
[t,y] = ode15s(@fun,tspan,y0,options);
I'm trying to solve the above system as a index-1 DAE. The first row and second row of the mass matrix will contain one's in the diagonal entries.
I am not sure how the left boundary condition has to be specified in the mass matrix.
Could someone explain?