> This needs the mass matrix M which is a block diagonal matrix and does not > change with time. I am planning to compute its inverse and store it. In the > RK scheme, I will just use vmult to multiply the inverse with the right > hand side, to get du/dt and update the solution. > > I am not sure how to compute/store the inverse.
If your matrix is block diagonal, the inverse is the matrix that consists of the inverse blocks. In other words, to store the inverse, rather than assemble the matrix of the blocks you compute on each cell and then invert the whole thing, you could compute the local contributions, invert them, and copy the inverses into the global matrix. W. ------------------------------------------------------------------------- Wolfgang Bangerth email: [email protected] www: http://www.math.tamu.edu/~bangerth/ _______________________________________________ dealii mailing list http://poisson.dealii.org/mailman/listinfo/dealii
