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annotate +rv/ResidualViscosity.m @ 1186:3364a51f0d9e feature/rv

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Add 1d shapiro filter function to ResidualViscosity
author Vidar Stiernström <vidar.stiernstrom@it.uu.se>
date Fri, 05 Jul 2019 19:08:37 +0200
parents beecb580c5bf
children 7173b6fd4063
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
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1 classdef ResidualViscosity < handle
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2 properties
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3 grid % grid
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4 Df % Diff op approximating the gradient of the flux f(u)
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5 waveSpeed % Wave speed at each grid point, e.g f'(u). %TBD: Better naming?
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6 Cmax % Constant controlling relative amount of upwind dissipation
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7 Cres % Constant controling relative amount of upwind dissipation
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8 h % Length scale used for scaling the viscosity. Typically grid spacing.
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9 normalization % Function used to normalize the residual such that it is amplified in the
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10 % shocks and suppressed elsewhere.
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11 Mres % Coefficients for the residual viscosity
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12 Mfirst % Coefficients for the first order viscosity
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13 fRes % Function handle for computing the residual.
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14 end
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15
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16 methods
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17 % TBD: Decide on how to treat waveSpeed. It would be nice to just pass a constant value without
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18 % wrapping it in a function.
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19 function obj = ResidualViscosity(grid, Df, waveSpeed, Cmax, Cres, h, normalization, postProcess)
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20 default_arg('normalization',@(v)abs(obj.minmaxDiffNeighborhood1d(v)-norm(v-mean(v),inf)));
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856bd6291d17 Use same order for both time derivative and flux term when computing the residual
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21 default_arg('postProcess','maximum neighbors');
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22 obj.Df = Df;
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23 obj.waveSpeed = waveSpeed;
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24 obj.h = h;
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25 obj.Cmax = Cmax;
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26
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27 obj.Cres = Cres;
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28 obj.normalization = normalization;
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29 obj.grid = grid;
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30 obj.Mres = obj.Cres*obj.h^2;
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31 obj.Mfirst = obj.Cmax*obj.h;
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32 switch postProcess
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33 case 'none'
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34 obj.fRes = @(v,dvdt) obj.Mres*abs(dvdt + obj.Df(v))./obj.normalization(v);
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35 case 'filter'
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36 F = obj.shapiroFilter(obj.grid, order);
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37 obj.fRes = @(v,dvdt) F*obj.Mres*abs(dvdt + obj.Df(v))./obj.normalization(v);
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38 case 'maximum neighbors'
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39 switch grid.D()
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40 case 1
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41 obj.fRes = @(v,dvdt) movmax(obj.Mres*abs(dvdt + obj.Df(v))./obj.normalization(v),3);
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42 case 2
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43 obj.fRes = @obj.maxResidualNeighbors2d;
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44 end
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45 end
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46 end
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47
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48 function viscosity = evaluateViscosity(obj, v, dvdt)
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49 viscosity = min(obj.Mfirst*abs(obj.waveSpeed(v)), obj.fRes(v,dvdt));
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50 end
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51
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2ef20d00b386 For easier comparison, return both the first order and residual viscosity when evaluating the residual. Add the first order and residual viscosity to the state of the RungekuttaRV time steppers
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52 function [viscosity, Df, firstOrderViscosity, residualViscosity] = evaluate(obj, v, dvdt)
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53 Df = obj.Df(v);
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54 firstOrderViscosity = obj.Mfirst*abs(obj.waveSpeed(v));
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55 residualViscosity = obj.fRes(v,dvdt);
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56 viscosity = min(firstOrderViscosity, residualViscosity);
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57 end
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58
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59 function res = maxResidualNeighbors2d(obj,v,dvdt)
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60 res = obj.Mres*abs(dvdt + obj.Df(v))./obj.normalization(v);
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61 resMat = grid.funcToMatrix(obj.grid,res);
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62 res = reshape(max(movmax(resMat,3,1),movmax(resMat,3,2))',obj.grid.N(),1);
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63 end
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64 end
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65 methods (Static)
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66 function minmaxDiff = minmaxDiffNeighborhood1d(u)
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67 umax = movmax(u,3);
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68 umin = movmin(u,3);
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69 minmaxDiff = umax - umin;
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70 end
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71
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72 function minmaxDiff = minmaxDiffNeighborhood2d(grid, u)
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73 uMatrix = grid.funcToMatrix(grid,u);
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74 umax = max(movmax(uMatrix,3,1),movmax(uMatrix,3,2));
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75 umin = min(movmin(uMatrix,3,1),movmin(uMatrix,3,2));
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76 minmaxDiff = umax - umin;
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77 minmaxDiff = reshape(minmaxDiff',g.N(),1);
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78 end
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79 function F = shapiroFilter(grid, order)
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80 switch order
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81 case 2
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82 F = spdiags(repmat([1 2 1],grid.m(1),1), -1:1, grid.m(1), grid.m(1));
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83 case 4
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84 F = spdiags(repmat([-1 4 10 4 -1],grid.m(1),1), -2:2, grid.m(1), grid.m(1));
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85 case 6
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86 F = spdiags(repmat([1 -6 15 44 15 -6 1],grid.m(1),1), -3:3, grid.m(1), grid.m(1));
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87 case 8
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88 F = spdiags(repmat([-1 8 -28 56 186 56 -28 8 -1],grid.m(1),1), -4:4, grid.m(1), grid.m(1));
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89 end
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90 F = 1/2^order * F;
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91 % Fx = spdiags(repmat(1/(mid+2)*[1 mid 1],g.m(1),1), -1:1, g.m(1), g.m(1));
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92 % Fx(1,:) = 0;
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93 % Fx(1,1:2) = 1/(mid+1)*[mid 1];
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94 % Fx(end,:) = 0;
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95 % Fx(end,end-1:end) = 1/(mid+1)*[1 mid];
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96 % Fy = spdiags(repmat(1/(mid+2)*[1 mid 1],g.m(2),1), -1:1, g.m(2), g.m(2));
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97 % Fy(1,:) = 0;
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98 % Fy(1,1:2) = 1/(mid+1)*[mid 1];
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99 % Fy(end,:) = 0;
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100 % Fy(end,end-1:end) = 1/(mid+1)*[1 mid];
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101 % Ix = speye(g.m(1));
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102 % Iy = speye(g.m(1));
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103 % F = kron(Fx, Iy) + kron(Ix, Fy);
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104 end
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105 end
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106
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107 end