Mercurial > repos > public > sbplib

annotate +rv/+time/RungekuttaExteriorRV.m @ 1013:eb441fbdf379 feature/advectionRV

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Draft implementation of RungeKutta with exterior RV updates - Draft class RungeKuttaExteriorRV which updates the residual using a BDF approximation of the derivtive outside of the RK stages. - Draft class for BDF derivative
author Vidar Stiernström <vidar.stiernstrom@it.uu.se>
date Wed, 05 Dec 2018 15:04:44 +0100
parents
children e547794a9407
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
1013
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
1 classdef RungekuttaExteriorRV < time.Timestepper
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
2 properties
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
3 F % RHS of the ODE
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
4 k % Time step
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
5 t % Time point
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
6 v % Solution vector
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
7 n % Time level
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
8 coeffs % The coefficents used for the RK time integration
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
9 RV % Residual Viscosity
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
10 v_prev % Solution vector at previous time levels, used for the RV update
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
11 DvDt % Function for computing the time deriative used for the RV update
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
12 end
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
13 methods
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
14
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
15 function obj = RungekuttaExteriorRV(F, k, t0, v0, RV, rkOrder, bdfOrder)
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
16 obj.F = F;
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
17 obj.k = k;
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
18 obj.t = t0;
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
19 obj.v = v0;
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
20 obj.n = 0;
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
21 % Extract the coefficients for the specified rkOrder
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
22 % used for the RK updates from the Butcher tableua.
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
23 [s,a,b,c] = time.rk.butcherTableau(rkOrder);
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
24 obj.coeffs = struct('s',s,'a',a,'b',b,'c',c);
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
25
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
26 obj.RV = RV;
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
27 % TODO: Initialize v_prev.
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
28 obj.v_prev = zeros(length(obj.v),bdfOrder);
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
29 % TBD: For cases where h~k we could probably use rkOrder-2 here.
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
30 obj.DvDt = rv.time.BDFDerivative(bdfOrder,k);
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
31 end
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
32
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
33 function [v, t] = getV(obj)
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
34 v = obj.v;
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
35 t = obj.t;
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
36 end
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
37
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
38 function state = getState(obj)
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
39 [residual, u_t, grad_f] = obj.RV.getResidual();
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
40 state = struct('v', obj.v, 'residual', residual, 'u_t', u_t, 'grad_f', grad_f, 'viscosity', obj.RV.getViscosity(), 't', obj.t);
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
41 end
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
42
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
43 function obj = step(obj)
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
44 % Store current time level
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
45 obj.v_prev(:,2:end) = obj.v_prev(:,1:end-1);
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
46 obj.v_prev(:,1) = obj.v;
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
47 % Fix the viscosity of the RHS function F
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
48 F_visc = @(v,t)F(v,t,obj.RV.getViscosity()); %Remove state in RV?
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
49 obj.v = time.rk.rungekutta(obj.v, obj.t, obj.k, F_visc, obj.RV, obj.coeffs);
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
50 % Calculate dvdt and update RV
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
51 dvdt = obj.DvDt.evaluate(v, v_prev, lenght(v_prev));
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
52 RV.update(v,dvdt);
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
53 obj.t = obj.t + obj.k;
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
54 obj.n = obj.n + 1;
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
55 end
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
56 end
eb441fbdf379 Draft implementation of RungeKutta with exterior RV updates
Vidar Stiernström <vidar.stiernstrom@it.uu.se>
parents:
diff changeset
57 end