1 | %'filter_tps': find the thin plate spline coefficients for interpolation-smoothing |
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2 | %------------------------------------------------------------------------ |
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3 | % [SubRange,NbCentre,Coord_tps,U_tps,V_tps,W_tps,U_smooth,V_smooth,W_smooth,FF] =filter_tps(Coord,U,V,W,SubDomainSize,Rho,Threshold) |
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4 | % |
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5 | % OUTPUT: |
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6 | % SubRange(NbCoord,NbSubdomain,2): range (min, max) of the coordiantes x and y respectively, for each subdomain |
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7 | % NbCentre(NbSubdomain): number of source points for each subdomain |
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8 | % FF: false flags |
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9 | % U_smooth, V_smooth: filtered velocity components at the positions of the initial data |
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10 | % Coord_tps(NbCentre,NbCoord,NbSubdomain): positions of the tps centres |
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11 | % U_tps,V_tps: weight of the tps for each subdomain |
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12 | % to get the interpolated field values, use the function calc_field.m |
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13 | % |
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14 | % INPUT: |
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15 | % coord=[X Y]: matrix whose first column is the x coordinates of the initial data, the second column the y coordiantes |
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16 | % U,V: set of velocity components of the initial data |
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17 | % Rho: smoothing parameter |
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18 | % Threshold: max diff accepted between smoothed and initial data |
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19 | % Subdomain: estimated number of data points in each subdomain |
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20 | |
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21 | %======================================================================= |
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22 | % Copyright 2008-2015, LEGI UMR 5519 / CNRS UJF G-INP, Grenoble, France |
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23 | % http://www.legi.grenoble-inp.fr |
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24 | % Joel.Sommeria - Joel.Sommeria (A) legi.cnrs.fr |
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25 | % |
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26 | % This file is part of the toolbox UVMAT. |
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27 | % |
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28 | % UVMAT is free software; you can redistribute it and/or modify |
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29 | % it under the terms of the GNU General Public License as published |
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30 | % by the Free Software Foundation; either version 2 of the license, |
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31 | % or (at your option) any later version. |
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32 | % |
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33 | % UVMAT is distributed in the hope that it will be useful, |
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34 | % but WITHOUT ANY WARRANTY; without even the implied warranty of |
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35 | % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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36 | % GNU General Public License (see LICENSE.txt) for more details. |
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37 | %======================================================================= |
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38 | |
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39 | function [SubRange,NbCentre,Coord_tps,U_tps,V_tps,W_tps,U_smooth,V_smooth,W_smooth,FF] =filter_tps(Coord,U,V,W,SubDomainSize,Rho,Threshold) |
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40 | |
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41 | %% adjust subdomain decomposition |
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42 | warning off |
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43 | NbVec=size(Coord,1);% nbre of vectors in the field to interpolate |
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44 | NbCoord=size(Coord,2);% space dimension |
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45 | MinCoord=min(Coord,[],1);%lower coordinate bounds |
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46 | MaxCoord=max(Coord,[],1);%upper coordinate bounds |
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47 | Range=MaxCoord-MinCoord; |
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48 | AspectRatio=Range(2)/Range(1); |
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49 | NbSubDomain=NbVec/SubDomainSize;% estimated number of subdomains |
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50 | NbSubDomainX=max(floor(sqrt(NbSubDomain/AspectRatio)),1);% estimated number of subdomains in x |
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51 | NbSubDomainY=max(floor(sqrt(NbSubDomain*AspectRatio)),1);% estimated number of subdomains in y |
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52 | NbSubDomain=NbSubDomainX*NbSubDomainY;% new estimated number of subdomains in a matrix shape partition in subdomains |
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53 | Siz(1)=Range(1)/NbSubDomainX;%width of subdomains |
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54 | Siz(2)=Range(2)/NbSubDomainY;%height of subdomains |
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55 | CentreX=linspace(MinCoord(1)+Siz(1)/2,MaxCoord(1)-Siz(1)/2,NbSubDomainX);% X positions of subdomain centres |
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56 | CentreY=linspace(MinCoord(2)+Siz(2)/2,MaxCoord(2)-Siz(2)/2,NbSubDomainY);% Y positions of subdomain centres |
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57 | [CentreX,CentreY]=meshgrid(CentreX,CentreY); |
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58 | CentreX=reshape(CentreX,1,[]);% X positions of subdomain centres |
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59 | CentreY=reshape(CentreY,1,[]);% Y positions of subdomain centres |
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60 | |
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61 | %% smoothing parameter |
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62 | rho=Siz(1)*Siz(2)*Rho/1000;%optimum rho increase as the area of the subdomain (division by 1000 to reach good values with the default GUI input) |
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63 | |
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64 | %% default output |
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65 | SubRange=zeros(NbCoord,2,NbSubDomain);%initialise the boundaries of subdomains |
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66 | Coord_tps=zeros(1,NbCoord,NbSubDomain);% initialize coordinates of interpolated data |
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67 | U_tps=zeros(1,NbSubDomain);% initialize interpolated u component |
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68 | V_tps=zeros(1,NbSubDomain);% initialize interpolated v component |
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69 | NbCentre=zeros(1,NbSubDomain);%number of interpolated field values per subdomain, =0 by default |
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70 | W_tps=[];%default (2 component case) |
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71 | U_smooth=zeros(NbVec,1); % smoothed velocity U at the initial positions |
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72 | V_smooth=zeros(NbVec,1);% smoothed velocity V at the initial positions |
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73 | W_smooth=[];%default (2 component case) |
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74 | FF=zeros(NbVec,1); |
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75 | nb_select=zeros(NbVec,1); |
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76 | check_empty=zeros(1,NbSubDomain); |
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77 | |
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78 | |
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79 | %% calculate tps coeff in each subdomain |
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80 | for isub=1:NbSubDomain |
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81 | SubRange(1,:,isub)=[CentreX(isub)-0.55*Siz(1) CentreX(isub)+0.55*Siz(1)];%bounds of subdomain #isub in x coordinate |
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82 | SubRange(2,:,isub)=[CentreY(isub)-0.55*Siz(2) CentreY(isub)+0.55*Siz(2)];%bounds of subdomain #isub in y coordinate |
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83 | ind_sel_previous=[]; |
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84 | ind_sel=0;%initialize set of vector indices in the subdomain |
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85 | %increase iteratively the subdomain if it contains less than SubDomainNbVec/4 source vectors |
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86 | while numel(ind_sel)>numel(ind_sel_previous) |
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87 | ind_sel_previous=ind_sel;% record the set of selected vector indices for next iteration |
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88 | ind_sel=find(Coord(:,1)>=SubRange(1,1,isub) & Coord(:,1)<=SubRange(1,2,isub) & Coord(:,2)>=SubRange(2,1,isub) & Coord(:,2)<=SubRange(2,2,isub)); |
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89 | % if no vector in the subdomain #isub, skip the subdomain |
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90 | if isempty(ind_sel) |
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91 | check_empty(isub)=1; |
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92 | break % go to next subdomain |
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93 | % if too few selected vectors, increase the subrange for next iteration |
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94 | elseif numel(ind_sel)<SubDomainSize/4 && ~isequal( ind_sel,ind_sel_previous); |
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95 | SubRange(:,1,isub)=SubRange(:,1,isub)-Siz'/4; |
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96 | SubRange(:,2,isub)=SubRange(:,2,isub)+Siz'/4; |
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97 | % subdomain includes enough vectors, perform tps interpolation |
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98 | else |
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99 | [U_smooth_sub,U_tps_sub]=tps_coeff(Coord(ind_sel,:),U(ind_sel),rho); |
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100 | [V_smooth_sub,V_tps_sub]=tps_coeff(Coord(ind_sel,:),V(ind_sel),rho); |
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101 | UDiff=U_smooth_sub-U(ind_sel);% difference between interpolated U component and initial value |
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102 | VDiff=V_smooth_sub-V(ind_sel);% difference between interpolated V component and initial value |
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103 | NormDiff=UDiff.*UDiff+VDiff.*VDiff;% Square of difference norm |
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104 | ind_ind_sel=1:numel(ind_sel);%default |
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105 | if exist('Threshold','var')&&~isempty(Threshold) |
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106 | FF(ind_sel)=20*(NormDiff>Threshold);%put FF value to 20 to identify the criterium of elimmination |
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107 | ind_ind_sel=find(FF(ind_sel)==0); % select the indices of ind_sel corresponding to the remaining vectors |
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108 | end |
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109 | % if no value exceeds threshold, the result is recorded |
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110 | if isequal(numel(ind_ind_sel),numel(ind_sel)) |
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111 | U_smooth(ind_sel)=U_smooth(ind_sel)+U_smooth_sub; |
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112 | V_smooth(ind_sel)=V_smooth(ind_sel)+V_smooth_sub; |
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113 | NbCentre(isub)=numel(ind_sel); |
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114 | Coord_tps(1:NbCentre(isub),:,isub)=Coord(ind_sel,:); |
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115 | U_tps(1:NbCentre(isub)+3,isub)=U_tps_sub; |
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116 | V_tps(1:NbCentre(isub)+3,isub)=V_tps_sub; |
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117 | nb_select(ind_sel)=nb_select(ind_sel)+1; |
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118 | display(['tps done in subdomain # ' num2str(isub) ' among ' num2str(NbSubDomain)]) |
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119 | break |
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120 | % if too few selected vectors, increase the subrange for next iteration |
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121 | elseif numel(ind_ind_sel)<SubDomainSize/4 && ~isequal( ind_sel,ind_sel_previous); |
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122 | SubRange(:,1,isub)=SubRange(:,1,isub)-Siz'/4; |
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123 | SubRange(:,2,isub)=SubRange(:,2,isub)+Siz'/4; |
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124 | % else interpolation-smoothing is done again with the selected vectors |
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125 | else |
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126 | [U_smooth_sub,U_tps_sub]=tps_coeff(Coord(ind_sel(ind_ind_sel),:),U(ind_sel(ind_ind_sel)),rho); |
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127 | [V_smooth_sub,V_tps_sub]=tps_coeff(Coord(ind_sel(ind_ind_sel),:),V(ind_sel(ind_ind_sel)),rho); |
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128 | U_smooth(ind_sel(ind_ind_sel))=U_smooth(ind_sel(ind_ind_sel))+U_smooth_sub; |
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129 | V_smooth(ind_sel(ind_ind_sel))=V_smooth(ind_sel(ind_ind_sel))+V_smooth_sub; |
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130 | NbCentre(isub)=numel(ind_ind_sel); |
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131 | Coord_tps(1:NbCentre(isub),:,isub)=Coord(ind_sel(ind_ind_sel),:); |
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132 | U_tps(1:NbCentre(isub)+3,isub)=U_tps_sub; |
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133 | V_tps(1:NbCentre(isub)+3,isub)=V_tps_sub; |
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134 | nb_select(ind_sel(ind_ind_sel))=nb_select(ind_sel(ind_ind_sel))+1; |
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135 | display(['tps redone after elimination of erratic vectors in subdomain # ' num2str(isub) ' among ' num2str(NbSubDomain)]) |
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136 | break |
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137 | end |
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138 | end |
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139 | end |
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140 | end |
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141 | |
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142 | %% remove empty subdomains |
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143 | ind_empty=find(check_empty); |
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144 | if ~isempty(ind_empty) |
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145 | SubRange(:,:,ind_empty)=[]; |
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146 | Coord_tps(:,:,ind_empty)=[]; |
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147 | U_tps(:,ind_empty)=[]; |
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148 | V_tps(:,ind_empty)=[]; |
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149 | NbCentre(ind_empty)=[]; |
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150 | end |
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151 | |
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152 | %% final adjustments |
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153 | nb_select(nb_select==0)=1; |
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154 | U_smooth=U_smooth./nb_select;% take the average at the intersection of several subdomains |
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155 | V_smooth=V_smooth./nb_select; |
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156 | fill=zeros(NbCoord+1,NbCoord,size(SubRange,3)); %matrix of zeros to complement the matrix Data.Civ1_Coord_tps (conveninent for file storage) |
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157 | Coord_tps=cat(1,Coord_tps,fill); |
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158 | |
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