Resolving discrepancy between the number of surfaces generated and the number of surface handles stored in cell array

Question

Vance Blake 2020-12-24

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评论： Vance Blake 2020-12-25

I am running an algorithm that generates different sized surfaces. However, when I try to store the surface handles in a cell array, I end up with more surface handles stored (59) than surfaces generated (50). I store the surface handles in the cell array h_SurfMatrix. Any help would be greatly appreciated.

clear
close all
clc
%A = 50 pts
A = [0,0,0;0.00977495601952172,0.0129188554738323,0.999868768093125;-0.566794094824837,-0.823750570492204,0.0133959578031223;0.0279587435128966,0.0380588867245362,1.99938731654588;0.830388266617646,0.583999369869120,0.978401571089338;-1.07826433834531,-1.64452537544960,0.267810795303313;0.168715496407312,0.263085998125572,2.96351922435162;-0.791458202545459,0.611268411797120,0.998070417818667;-1.41124221175034,-0.289407593850698,0.0506110237693017;1.69942938355116,1.04462646221878,1.15892918358242;-1.55216375501531,-2.44987966243271,0.623934110066297;0.188310075544404,0.501770043093754,3.93441879647330;-1.44603145623221,1.35107113546187,1.15371676572365;-2.35391403973316,0.0183196401577155,0.179737992978120;2.59879677816763,1.38804628951095,1.42948622326796;-1.92629974765512,-3.28302931738291,1.03122259685150;0.190461468181228,0.731318108759712,4.90771374511875;-2.01837467713375,2.14014570650778,1.37684130228734;-3.30531517848174,0.217844651708771,0.414313445558867;3.50709118523837,1.65551615551852,1.75113998255253;-2.23204460424917,-4.13488361866807,1.45650407075820;0.193343935566412,0.934427321909631,5.88686559182864;-2.51244231909718,2.97180232130260,1.63030617210704;-4.25650570961388,0.357419056329789,0.689550723301627;4.41845060685608,1.87363023778730,2.10021053665969;-2.47842156351806,-4.99324597672323,1.90651791078471;0.204283419234320,1.13357858075284,6.86677329350173;0.617793464714887,0.0559247730198438,6.10612769252045;-2.96417360323821,3.81704174520463,1.91580426879081;-5.20242439373799,0.476408999682868,0.991344090368801;5.32672360772571,2.06445068867013,2.47253796167180;-2.69346338350278,-5.85030685131976,2.37470982965291;0.218591936197924,1.32878562119851,7.84743096960627;-3.26247612265381,-4.91985596911837,1.29018005288354;1.20197539596291,-0.580347098756520,6.61000225666269;-3.37592827171665,4.67443410026770,2.22457026832058;-6.14584567995603,0.584770610127789,1.30473528056482;6.23299868743130,2.22581272192086,2.86321400922248;-2.89467385558292,-6.70726873056154,2.84918921113506;0.209717491582492,1.53184472980862,8.82655723451965;5.28440710514136,1.17097130314088,2.91964410258613;0.576278852478300,2.24513662818586,7.66753960818188;-4.04653068178957,-4.84646596151352,0.673842194982372;1.72465217643194,-1.18852390077965,7.20743841278270;-3.76500316313530,5.53715317053961,2.54758193166533;-7.08499357301506,0.666849489054822,1.63829830698843;7.13773556686645,2.38268963160310,3.25924533904186;-3.08850223839479,-7.56458389242937,3.32609724340970;0.176682672356017,1.77636612069925,9.79563823738556;5.70892694024996,0.283366758099107,3.09836478191717];
SizeA = size(A,1);
x = A(:, 1);
y = A(:, 2);
z = A(:, 3);
dist1a = nan(numel(x));
proximity = 1.000;
save_criteria = 3;
save_criteria2 = 2;
for i = 1:SizeA
    for j = 1:(i-1)
        dist1a(i,j) = sqrt((x(i)-x(j)).^2 + (y(i)-y(j)).^2 + (z(i)-z(j)).^2);
        dist1a(j,i) = dist1a(i,j);
    end
end
i2keep = find(sum((dist1a - proximity <= eps('single')), 2) >= save_criteria);
i2keep2 = find(sum((dist1a - proximity <= eps('single')), 2) >= save_criteria2);
keep_x1 = x(i2keep);
keep_y1 = y(i2keep);
keep_z1 = z(i2keep);
B = [keep_x1, keep_y1, keep_z1];
C = 1:SizeA;
index = ismember(C,i2keep2);
D = A(~index,:);
E = A(index,:);
%%
col = 1;
[master_index,~] = find(~index');
master_index_size = size(master_index,1);
indx = zeros(master_index_size,1);
    for i = 1:master_index_size
        while master_index(i,end) ~= 1
            col = col+1;
            indx = master_index(i,col-1);
            F = A(indx,:);
            master_index(i,col) = knnsearch(A(1:indx-1,:),F);
            if master_index(i,col) == 1
                break
            end
        end
        col = 1;
    end
master_index = flip(master_index,2);
%%
x_c = 0;
y_c = 0;
z_c = 0;
Center_Root = [x_c, y_c, z_c];
[x_dom,y_dom,z_dom] = sphere(80);   % Create Sphere
x_dom = x_dom(41:end,:);        % Keep top 41 x points
y_dom = y_dom(41:end,:);        % Keep top 41 y points
z_dom = z_dom(41:end,:);        % Keep top 41 z points
hemisphere_radius = 80;
figure;
Hemi_sf = surf(hemisphere_radius.*x_dom,hemisphere_radius.*y_dom,hemisphere_radius.*z_dom, 'FaceColor','#4DBEEE','EdgeColor', 'none');
alpha 0.2
hold on
radii_plane = 80;
center_plane = [x_c, y_c]; % center point of circular plane
viscircles(center_plane, radii_plane, 'color', '#77AC30');
scale = 1;
s = 4*scale;
used_index = [];
h_SurfMatrix = [];
for i = 1:size(master_index,1)
    branch = master_index(i,:);
    branch(branch == 0) = [];
    for j = 1:length(branch)
        if ismember(branch(1,j), i2keep)
            s = s*2^(-1/3);
        end
        if ismember(branch(1,j),used_index)
            h{j,:} = [];
            continue
        end
        [x_loc,y_loc,z_loc, spheresXYZ{i,j}] = createspheres(A(branch(1,j),1),A(branch(1,j),2),A(branch(1,j),3), s);
        h{j,:} = surf(x_loc+A(branch(1,j),1), y_loc+A(branch(1,j),2), z_loc+A(branch(1,j),3), 'FaceColor', 'k');
        h = h(~any(cellfun('isempty', h), 2), :);
        used_index = [used_index;branch(1,j)];
    end
    h_SurfMatrix = [h_SurfMatrix;h];
    s = 4*scale;
end
function [X,Y,Z,spheresXYZ] = createspheres(spherex, spherey, spherez, s)
[x, y, z] = sphere(11);
X = (s*x)+spherex;
Y = (s*y)+spherey;
Z = (s*z)+spherez;
spheresXYZ = [X,Y,Z];
end

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Answer 1

Adam Danz 2020-12-24

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/701492-resolving-discrepancy-between-the-number-of-surfaces-generated-and-the-number-of-surface-handles-sto#answer_583847

编辑：Adam Danz 2020-12-24

在 MATLAB Online 中打开

You're experiencing problems that often occur when loop variables are not preallocated.

When i==1, the j-loop has 10 iterations so h will be a 10x1 cell array.
When i==2, the j-loop has 9 iterations but since you are not preallocating the h-array, h still is 10x1 even though the j-loop only has 9 iterations. So h{10} shouldn't be there when i==2.

To fix that, preallocate h

for i = 1:size(master_index,1)
    branch = master_index(i,:);
    branch(branch == 0) = [];
    h = cell(numel(branch),1);   % <--------
    for j = 1:numel(branch)
        if ismember(branch(1,j), i2keep)

Also, avoid using length(); use size() or numel() instead. Here's a nice discussion on that topic.

So, the main lesson is: always preallocate loop variables.

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Vance Blake 2020-12-25

Sorry Im just seeing this. The email this account is attached to doesnt sync on my phone no matter what I do. Thank you so much!

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Resolving discrepancy between the number of surfaces generated and the number of surface handles stored in cell array

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