Surface plots inside loop
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Hi,
I am working on a code that approximates a general bivariate function using a piecewise linear bivariate function. I am able to retrieve the data and plot it, my code works as follows:
It plots one subdomain at a time, as a surface plot. The plot is put inside a loop and so during each, iteration a new subdomain is plotted.
The issue here is that the final plot is displayed with discontinuities as shown in the figure attached.
Kindly help me remove those discontinuities, so as to make the final plot solid or suggest any alternate idea that would work.
采纳的回答
darova
2019-8-19
0 个投票
Just collected all data and used griddata()
4 个评论
Mahesh M S
2019-8-19
Mahesh M S
2019-8-20
Thank you for the code. It works fine for the above case.
But, the dummy code I provided was a bit specific. I tried to run the code with necessary modifications on a more general case and I am stuck with an error. Kindly help me rectify it.
The code is given below:
xdata = xlsread('debug2.xlsx','B1:AO7');
ydata = xlsread('debug2.xlsx','B9:AO15');
%The whole domain is a square with x_min = 0.2, y_min = 0.2, x_max = pi/2 &
%y_max = pi/2
%The whole domain is divided into 7 parts (sample code) and F{i}
%corresponds to the function values of each subdomain
%Here, F{1} is the subdomain bounded by X{1} and Y{1}
% F{2} is the subdomain bounded by X{2} and Y{2}
% F{3} is the subdomain bounded by X{3} and Y{3}
% F{4} is the subdomain bounded by X{4} and Y{4}
% F{5} is the subdomain bounded by X{5} and Y{5}
% F{6} is the subdomain bounded by X{6} and Y{6}
% F{7} is the subdomain bounded by X{7} and Y{7}
X{1} = xdata(1,1:20); X{2} = xdata(2,1:20); X{3} = xdata(3,1:20); X{4} = xdata(4,:);
X{5} = xdata(5,:); X{6} = xdata(6,:); X{7} = xdata(7,:);
Y{1} = ydata(1,1:20); Y{2} = ydata(2,1:20); Y{3} = ydata(3,1:20); Y{4} = ydata(4,:);
Y{5} = ydata(5,:); Y{6} = ydata(6,:); Y{7} = ydata(7,:);
F{1} = xlsread('debug2.xlsx','B18:U37');
F{2} = xlsread('debug2.xlsx','B39:U58');
F{3} = xlsread('debug2.xlsx','B60:U79');
F{4} = xlsread('debug2.xlsx','B81:AO120');
F{5} = xlsread('debug2.xlsx','B122:AO161');
F{6} = xlsread('debug2.xlsx','B163:AO202');
F{7} = xlsread('debug2.xlsx','B204:AO243');
l = 7;
%The requirement is to plot the total domain in a single plot
% Note: The size of X{i} and Y{i} can vary and also value of l can vary.
X = [];
Y = [];
Z = [];
% make all data in one array
for i = 1:7
[X0, Y0] = meshgrid(xdata(i,:),ydata(i,:));
X = [X; X0(:)];
Y = [Y; Y0(:)];
Z = [Z; F{i}(:)];
end
% create new mesh
x1 = linspace(min(xdata(:)), max(xdata(:)),40);
y1 = linspace(min(ydata(:)), max(ydata(:)),40);
[X1, Y1] = meshgrid(x1,y1);
% create set of data
Z1 = griddata(X,Y,Z,X1,Y1);
h = surf(X1,Y1,Z1);
set(h,'LineStyle','none');
I am getting the following error:
Mahesh M S
2019-8-20
更多回答（3 个）
KSSV
2019-8-19
YOu can follow a samll demo code given here:
[X,Y,Z] = peaks(100) ;
surf(X,Y,Z)
%% Make surface discontinuous for demo
idx = meshgrid(10:10:100) ;
for i = 1:idx
Z(idx(:,i),:) = NaN ;
Z(:,idx(:,i)) = NaN ;
end
surf(X,Y,Z)
%% Have a continuous (x,y,z) data
idx = ~isnan(Z) ;
c = [X(idx) Y(idx) Z(idx)] ;
%% Make c continuous
x = c(:,1) ; y = c(:,2) ; z = c(:,3) ;
xi = linspace(min(x),max(x),100) ;
yi = linspace(min(y),max(y),100) ;
[X,Y] = meshgrid(xi,yi) ;
Z = NaN(size(X)) ;
% get nearest neighbors of new X, Y from (x,y)
idx = knnsearch([X(:) Y(:)],[x y]) ;
Z(idx) = z ;
%% fill gaps by interpolation
F = scatteredInterpolant(x,y,z) ;
idx = isnan(Z) ;
Z(idx) = F(X(idx),Y(idx)) ;
figure
surf(X,Y,Z)
YOu can also use griddata, fillgaps, fillmissing.
3 个评论
Mahesh M S
2019-8-19
编辑：Mahesh M S
2019-8-19
Thanks for the code. But, my code doesnt have gaps as such (as depicted by the top view of the figure shown below) [The figure has been updated. sorry for the error].
Its just discontinuous.
Aso, I can only retrieve data of one subdomain at a time (loop) and thus interpolation is also difficult. A possible way is to extract all data separately from each subdomain and plot later but it takes a lot of time which I am not happy with.
Kinldy help me out with this.
darova
2019-8-19
i can extract it for you
Mahesh M S
2019-8-19
Mahesh M S
2019-8-19
编辑：Mahesh M S
2019-8-19
Bruno Luong
2019-8-20
编辑：Bruno Luong
2019-8-20
Assuming your xdata and ydata are sorted. My code doest not make new resampling of x and y, or interpolation, I just stitch them together
% Read your data
xdata = xlsread('debug.xlsx','B1:U4');
ydata = xlsread('debug.xlsx','B6:U9');
X{1} = xdata(1,:); X{2} = xdata(2,:); X{3} = xdata(3,:); X{4} = xdata(4,:);
Y{1} = ydata(1,:); Y{2} = ydata(2,:); Y{3} = ydata(3,:); Y{4} = ydata(4,:);
F{1} = xlsread('debug.xlsx','B11:U30');
F{2} = xlsread('debug.xlsx','B32:U51');
F{3} = xlsread('debug.xlsx','B53:U72');
F{4} = xlsread('debug.xlsx','B74:U93');
% Stitching the sub-rectangule data
Xu = unique([X{:}]);
Yu = unique([Y{:}]);
Fu = nan(length(Yu),length(Yu));
for k=1:length(F)
[~,ix] = ismember(X{k},Xu);
[~,iy] = ismember(Y{k},Yu);
Fu(iy,ix) = F{k};
end
figure;
surf(Xu,Yu,Fu)
6 个评论
Mahesh M S
2019-8-20
Bruno Luong
2019-8-20
编辑：Bruno Luong
2019-8-20
It's up to you. I can only work on what is available since you haven't described precisely how the data looks like.
And please DO NOT attach Excel file this is proprietary format.
Mahesh M S
2019-8-20
编辑：Mahesh M S
2019-8-20
Bruno Luong
2019-8-20
MATFILE, we are all working with MATLAB here.
Mahesh M S
2019-8-20
Bruno Luong
2019-8-20
load('datareqd.mat')
% Stitching the sub-rectangule data
Xu = unique([X{:}]);
Yu = unique([Y{:}]);
Fu = nan(length(Yu),length(Yu));
for k=1:length(F)
[~,ix] = ismember(X{k},Xu);
[~,iy] = ismember(Y{k},Yu);
Fu(iy,ix) = F{k};
end
Fu = fillmissing(Fu,'linear');
close all
surf(Xu,Yu,Fu)
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