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comparison +rv/+time/RungekuttaExteriorRv.m @ 1152:010bb2677230 feature/rv

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Clean up in +rv/+time. Make the time stepping more efficient by not storing unnessecary properties in the RK-RV time steppers
author Vidar Stiernström <vidar.stiernstrom@it.uu.se>
date Tue, 05 Mar 2019 10:53:34 +0100
parents 2ef20d00b386
children 3108963cc42c
comparison
equal deleted inserted replaced
1151:03ecf18d035f 1152:010bb2677230
4 k % Time step 4 k % Time step
5 t % Time point 5 t % Time point
6 v % Solution vector 6 v % Solution vector
7 n % Time level 7 n % Time level
8 coeffs % The coefficents used for the RK time integration 8 coeffs % The coefficents used for the RK time integration
9
10 % Properties related to the residual viscositys
11 RV % Residual Viscosity operator 9 RV % Residual Viscosity operator
12 v_prev % Solution vector at previous time levels, used for the RV evaluation
13 DvDt % Function for computing the time deriative used for the RV evaluation 10 DvDt % Function for computing the time deriative used for the RV evaluation
14 lowerBdfOrder % Orders of the approximation of the time deriative, used for the RV evaluation.
15 % dictates which accuracy the boot-strapping should start from.
16 upperBdfOrder % Orders of the approximation of the time deriative, used for the RV evaluation.
17 % Dictates the order of accuracy used once the boot-strapping is complete.
18
19 % Convenience properties. Only for plotting
20 viscosity % Total viscosity
21 residualViscosity % Residual viscosity
22 firstOrderViscosity % first order viscosity
23 dvdt % Evaluated time derivative in residual
24 Df % Evaluated flux in residual
25 end 11 end
26 methods 12 methods
27 13
28 function obj = RungekuttaExteriorRv(F, k, t0, v0, RV, DvDt, order) 14 function obj = RungekuttaExteriorRv(F, k, t0, v0, RV, DvDt, order)
29 obj.F = F; 15 obj.F = F;
36 [s,a,b,c] = time.rk.butcherTableau(order); 22 [s,a,b,c] = time.rk.butcherTableau(order);
37 obj.coeffs = struct('s',s,'a',a,'b',b,'c',c); 23 obj.coeffs = struct('s',s,'a',a,'b',b,'c',c);
38 24
39 obj.RV = RV; 25 obj.RV = RV;
40 obj.DvDt = DvDt; 26 obj.DvDt = DvDt;
41 obj.dvdt = obj.DvDt(obj.v);
42 [obj.viscosity, obj.Df, obj.firstOrderViscosity, obj.residualViscosity] = RV.evaluate(obj.v,obj.dvdt);
43 end 27 end
44 28
45 function [v, t] = getV(obj) 29 function [v, t] = getV(obj)
46 v = obj.v; 30 v = obj.v;
47 t = obj.t; 31 t = obj.t;
48 end 32 end
49 33
50 function state = getState(obj) 34 function state = getState(obj)
51 state = struct('v', obj.v, 'dvdt', obj.dvdt, 'Df', obj.Df, 'viscosity', obj.viscosity, 'residualViscosity', obj.residualViscosity, 'firstOrderViscosity', obj.firstOrderViscosity, 't', obj.t); 35 dvdt = obj.DvDt(obj.v);
36 [viscosity, Df, firstOrderViscosity, residualViscosity] = obj.RV.evaluate(obj.v, dvdt);
37 state = struct('v', obj.v, 'dvdt', dvdt, 'Df', Df, 'viscosity', viscosity, 'residualViscosity', residualViscosity, 'firstOrderViscosity', firstOrderViscosity, 't', obj.t);
52 end 38 end
53 39
40 % Advances the solution vector one time step using the Runge-Kutta method given by
41 % obj.coeffs, using a fixed residual viscosity for the Runge-Kutta substeps
54 function obj = step(obj) 42 function obj = step(obj)
55 obj.dvdt = obj.DvDt(obj.v);
56 [obj.viscosity, obj.Df, obj.firstOrderViscosity, obj.residualViscosity] = obj.RV.evaluate(obj.v,obj.dvdt);
57
58 % Fix the viscosity of the RHS function F 43 % Fix the viscosity of the RHS function F
59 F_visc = @(v,t) obj.F(v,t,obj.viscosity); 44 F_visc = @(v,t) obj.F(v,t,obj.RV.evaluateViscosity(obj.v, obj.DvDt(obj.v)));
60 obj.v = time.rk.rungekutta(obj.v, obj.t, obj.k, F_visc, obj.coeffs); 45 obj.v = time.rk.rungekutta(obj.v, obj.t, obj.k, F_visc, obj.coeffs);
61 obj.t = obj.t + obj.k; 46 obj.t = obj.t + obj.k;
62 obj.n = obj.n + 1; 47 obj.n = obj.n + 1;
63 end 48 end
64 end 49 end