I cannot extract data from syms surface plot: Struct contents reference from a non-struct array object

Hi!,

When I am trying to extract (x,y,z) data from a surface plot generated by the following code:

syms q_par_pipi_2 q_perp_pipi_2 Chi_xx_pipi_2

qx_pipi_2=q_par_pipi_2./sqrt(2);

Gamma_q_par_pi0_1=(1/2)*(cos(q_par_pi0_1)+1);

omega_bq_par_pi0_1=2*J*sqrt((1-Gamma_q_par_pi0_1)*(1+Gamma_q_par_pi0_1+J_perp_1/(2*J)));

omega_aq_par_pi0_1=2*J*sqrt((1+Gamma_q_par_pi0_1)*(1-Gamma_q_par_pi0_1+J_perp_1/(2*J)));

A1=q_perp_pi0_1*d/2;

B1=J*(1-Gamma_q_par_pi0_1)/omega_bq_par_pi0_1;

C1=(J*(1-Gamma_q_par_pi0_1)+(1/2)*J_perp_1)/omega_aq_par_pi0_1;

Chi_xx_pi0_1=(cos(A1)^2)*B1+(sin(A1)^2)*C1;

fsurf(Chi_xx_pi0_1,[0 1 0 1],'DisplayName','(pi,0), J_perp = + 0.5J',...

'Parent',axes1,...

'FaceColor',[0.749019622802734 0.749019622802734 0]);

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

h = gcf; %current figure handle

axesObjs = get(h, 'Children'); %axes handles

dataObjs = get(axesObjs, 'Children'); %handles to low-level graphics objects in axes

%%get data

XX = dataObjs.XData ;

YY = dataObjs.YData ;

ZZ = dataObjs.ZData ;

I am getting the following error: Struct contents reference from a non-struct array object.

The plot is fine, but cannot extract any data.

The second part works normally with surface plots generated from non-syms generated plots.

Can you please help me understand? Is there any other way?

Answer 1

[Star Strider]

I can’t run the posted code because there are missing elements.

Neverhteless, everything necessary to extract the data and reconstruct it as a surf plot is available, although it takes a bit of effort to retrieve it and put it in a form that surf can use —

syms x y 
f(x,y) = exp(-(x-5)^2/5) + exp(-(y-5)^2/5)

f(x, y) = 

figure
hfp = fsurf(f, [0  10    -5  15]);
legend('Location','best')

% GetPlotHandleData = get(hfp)
Xv = hfp.XData;
Yv = hfp.YData;
Zv = hfp.ZData;
% Ax = gca;
% xt = Ax.XTick
% yt = Ax.YTick
% zt = Ax.ZTick

Xm = reshape(Xv(1:hfp.MeshDensity^2), hfp.MeshDensity, []);             % Create Matrix From Vector
Ym = reshape(Yv(1:hfp.MeshDensity^2), hfp.MeshDensity, []);             % Create Matrix From Vector
Zm = reshape(Zv(1:hfp.MeshDensity^2), hfp.MeshDensity, []);             % Create Matrix From Vector

figure
surf(Xm, Ym, Zm)

I am not certain how general this is since I only tested it on this function with these limits. It should get you started with your data.

.

[Star Strider]

As always, my pleasure!

Answer 2

[Subhrangsu Sarkar]

Thank you very much!