Change size 3D matrix

Question

Francesco Guaresi 2019-11-2

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/488818-change-size-3d-matrix

评论： the cyclist 2019-11-2

Hi, I have a 3D matrix defined as: EP(N,k,r) and I want to plot its values as different surfaces at constant N. So I tried to plot this matrix in this way:

col=hsv(N);
figure
hold on
for f=1:N
    surf(vector_1,vector_2,EP(f,:,:),'Color',col(f,:,:));
    legendInfo{f} = [num2str(Temp(f)-273.15) ' °C'];
end
legend(legendInfo)

but it doesn't work. It seems I can only plot surfaces at constant r! So now I want to try to plot a new matrix in the form (k,r,N).

How can I change the dimension of matrix EP(N,k,r) (and so its values inside) in this form: EP_1(k,r,N)?

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the cyclist 2019-11-2

When you say, "it doesn't work", what do you mean, specifically? Do you mean that the code runs, but gives an unexpected result, or that the code does not run, and gives an error? If that latter, please post the complete error message.

Francesco Guaresi 2019-11-2

编辑：Francesco Guaresi 2019-11-2

The entire code works, except this plot. The error message is:

Error using surf (line 71)

Z must be a matrix, not a scalar or vector.

Error in Isothermal_PFR_EP3_tensor_plot_3D (line 437)

surf(vector_1,vector_2,EP(f,:,:),'Color',col(f,:,:));

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Answer 1

the cyclist 2019-11-2

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链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/488818-change-size-3d-matrix#answer_399465

在 MATLAB Online 中打开

I think what you want is to use

permute(EP(f,:,:),[2 3 1])

as the input, instead of just EP(f,:,:), so that you have a 2-d matrix, rather than a 3-d (in which the first dimension has length 1).

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Francesco Guaresi 2019-11-2

在 MATLAB Online 中打开

plotting_3D_matrix.m

Yes! I've written this matlab file (the original one is more long):

clc
clear all
close all
Temp = [600 650 700 750] + 273.15;
xV_vector = [.2 .3 .4 .5 .6];
H_D_ratio = [6 7 8 9 10];
N = max(size(Temp));
k = max(size(xV_vector));
r = max(size(H_D_ratio));
col=hsv(N);
% EP3 matrix is generated by other computations in my original matlab file,
% here below the values obtained:
EP3(:,:,1) = 1.0e+06 * [2.4819    2.7183    2.2334    1.1416   -0.8249;
                        3.7156    3.5296    2.8405    1.6296   -0.4149;
                        4.1008    3.7800    3.0269    1.7778   -0.2913;
                        4.2139    3.8495    3.0761    1.8155   -0.2609];
EP3(:,:,2) = 1.0e+06 * [2.4255    2.6808    2.2051    1.1186   -0.8443;
                        3.6950    3.5158    2.8300    1.6211   -0.4221;
                        4.0924    3.7743    3.0225    1.7743   -0.2943;
                        4.2101    3.8469    3.0741    1.8139   -0.2623];
EP3(:,:,3) = 1.0e+06 * [2.3754    2.6474    2.1799    1.0982   -0.8615;
                        3.6767    3.5036    2.8207    1.6135   -0.4285;
                        4.0849    3.7693    3.0187    1.7712   -0.2969;
                        4.2068    3.8446    3.0724    1.8125   -0.2635];
EP3(:,:,4) = 1.0e+06 * [2.3301    2.6173    2.1571    1.0798   -0.8771;
                        3.6601    3.4925    2.8123    1.6067   -0.4343;
                        4.0781    3.7647    3.0152    1.7683   -0.2993;
                        4.2037    3.8426    3.0708    1.8112   -0.2646];
EP3(:,:,5) = 1.0e+06 * [2.2888    2.5899    2.1364    1.0630   -0.8913;
                        3.6450    3.4824    2.8046    1.6005   -0.4395;
                        4.0719    3.7606    3.0120    1.7658   -0.3015;
                        4.2009    3.8407    3.0694    1.8100   -0.2656];
% dimensions of matrix EP3: [N,k,r]
[Xgrid,Ygrid]=meshgrid(xV_vector,H_D_ratio);
EP3_grid = permute(EP3,[2 3 1]);
figure
hold on
for f=1:N
    surf(Xgrid,Ygrid,EP3_grid(:,:,f)'); %,'Color',col(:,:,f));
    legendInfo{f} = [num2str(Temp(f)-273.15) ' °C'];
end
xticks(xV_vector);
yticks(H_D_ratio);
title 'EP_3'
xlabel 'x_v (molar fraction of H_2 in V and R) [-]', ylabel 'H/D reactor ratio [-]'
zlabel('EP_3')
legend(legendInfo)
%s.EdgeColor='none';