Mercurial > repos > public > sbplib
comparison +rv/+time/RungeKuttaRvInstage.m @ 1181:9ac86ccfd6a1 feature/rv
Move instage rungekutta time stepping to RungekuttaRvInstage
| author | Vidar Stiernström <vidar.stiernstrom@it.uu.se> |
|---|---|
| date | Fri, 05 Jul 2019 16:51:05 +0200 |
| parents | d02e5b8a0b24 |
| children |
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| 1180:beecb580c5bf | 1181:9ac86ccfd6a1 |
|---|---|
| 42 obj.v = rv.time.rungekuttaRV(obj.v, obj.t, obj.k, obj.F, obj.RV, obj.DvDt, obj.coeffs); | 42 obj.v = rv.time.rungekuttaRV(obj.v, obj.t, obj.k, obj.F, obj.RV, obj.DvDt, obj.coeffs); |
| 43 obj.t = obj.t + obj.k; | 43 obj.t = obj.t + obj.k; |
| 44 obj.n = obj.n + 1; | 44 obj.n = obj.n + 1; |
| 45 end | 45 end |
| 46 end | 46 end |
| 47 | |
| 48 % Takes one time step of size dt using the rungekutta method | |
| 49 % starting from v and where the function F(v,t,RV) gives the | |
| 50 % time derivatives. coeffs is a struct holding the RK coefficients | |
| 51 % for the specific method. RV is the residual viscosity which is updated | |
| 52 % in between the stages and after the updated solution is computed. | |
| 53 methods (Static) | |
| 54 function v = rungekuttaRV(v, t , dt, F, RV, DvDt, coeffs) | |
| 55 % Move one stage outside to avoid branching for updating the | |
| 56 % residual inside the loop. | |
| 57 k = zeros(length(v), coeffs.s); | |
| 58 k(:,1) = F(v,t,RV.evaluateViscosity(v,DvDt(v))); | |
| 59 | |
| 60 % Compute the intermediate stages k | |
| 61 for i = 2:coeffs.s | |
| 62 u = v; | |
| 63 for j = 1:i-1 | |
| 64 u = u + dt*coeffs.a(i,j)*k(:,j); | |
| 65 end | |
| 66 k(:,i) = F(u,t+coeffs.c(i)*dt, RV.evaluateViscosity(u,DvDt(u))); | |
| 67 end | |
| 68 | |
| 69 % Compute the updated solution as a linear combination | |
| 70 % of the intermediate stages. | |
| 71 u = v; | |
| 72 for i = 1:coeffs.s | |
| 73 u = u + dt*coeffs.b(i)*k(:,i); | |
| 74 end | |
| 75 v = u; | |
| 76 end | |
| 77 | |
| 78 | |
| 47 end | 79 end |