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comparison +rv/+time/rungekuttaRV.m @ 1012:1e437c9e5132 feature/advectionRV

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Create residual viscosity package +rv and generalize the ResidualViscosity class - Generalize residual viscosity, by passing user-defined flux and calculating the time derivative outside of the update. - Create separate RungekuttaRV specifically using interior RV updates - Separate the artifical dissipation operator from the scheme AdvectionRV1D so that the same scheme can be reused for creating the diff op used by the ResidualViscosity class
author Vidar Stiernström <vidar.stiernstrom@it.uu.se>
date Wed, 05 Dec 2018 13:44:10 +0100
parents +time/+rk/rungekuttaRV.m@1c6f1595bb94
children 2d7c1333bd6c
comparison
equal deleted inserted replaced
1011:e0560bc4fb7d 1012:1e437c9e5132
1 % Takes one time step of size dt using the rungekutta method
2 % starting from v and where the function F(v,t,RV) gives the
3 % time derivatives. coeffs is a struct holding the RK coefficients
4 % for the specific method. RV is the residual viscosity which is updated
5 % in between the stages and after the updated solution is computed.
6 function v = rungekuttaRV(v, t , dt, F, RV, coeffs)
7 % Move one stage outside to avoid branching for updating the
8 % residual inside the loop.
9 k = zeros(length(v), coeffs.s);
10 k(:,1) = F(v,t,RV.getViscosity());
11
12 % Compute the intermediate stages k
13 for i = 2:coeffs.s
14 u = v;
15 for j = 1:i-1
16 u = u + dt*coeffs.a(i,j)*k(:,j);
17 end
18 RV.update(0.5*(u+v),(u-v)/(coeffs.c(i)*dt)); % Crank-Nicholson for time discretization
19 k(:,i) = F(u,t+coeffs.c(i)*dt, RV.getViscosity());
20 end
21
22 % Compute the updated solution as a linear combination
23 % of the intermediate stages.
24 u = v;
25 for i = 1:coeffs.s
26 u = u + dt*coeffs.b(i)*k(:,i);
27 end
28 RV.update(0.5*(u+v),(u-v)/dt); % Crank-Nicholson for time discretization
29 v = u;
30 end