Matlab plot 4D data

I want to plot 4d data on space x+y+z<=1,x>=0,y>=0,z>=0, so I use the following code

i=1;
for p=0:0.01:1
    for q=0:0.01:1-p
        for r=0:0.01:1-p-q
            [ua,ub]=BNE(p,q,r);
            E(i)=ua+ub;
            x(i)=p;
            y(i)=q;
            z(i)=r;
            i=i+1;
        end
    end
end
[X,Y,Z]=meshgrid(x,y,z);
surf(X,Y,Z,E)

But it failed. How plot the data (x,y,z,E). Where BNE() is the self-defining function.

Answer 1

[Keita Abe]

I found that two points for reconsindering

• meshgrid function requires unique array of x, y, z.
• surf function requires the surface definition but your input is volume data

If you would like to know the isosurface, I hope the following code would be helpful. Or if you would like to define the surface, the following link will be helpful. 2 次元または 3 次元の散布データの内挿 - MATLAB griddata - MathWorks 日本

i=1;
for p=0:0.01:1
    for q=0:0.01:1-p
        for r=0:0.01:1-p-q
            [ua,ub]=BNE(p,q,r);
            E(i)=ua+ub;
            x(i)=p;
            y(i)=q;
            z(i)=r;
            i=i+1;
        end
    end
end

[X,Y,Z]=meshgrid(unique(x),unique(y),unique(z));
vq = griddata(x,y,z,E,X,Y,Z);

isosurface(X,Y,Z,vq,0.5)

function [ua, ub] = BNE(p,q,r)
    ua = p+q;
    ub = q+r;
end