MATLAB: Attempt to execute SCRIPT surfnorm as a function:

quiver3surfnorm

Hi, I'm attempting to use the surfnorm function to produce a set of perpendicular vectors to a hemisphere.

I have used this function before without problem but I have been having some issues. Here is the code

R=22; phi=linspace(0,pi,50); theta=linspace(-pi/2,pi/2,50);
[phi,theta]=meshgrid(phi,theta);
X=R*sin(phi).*cos(theta); Y=R*sin(phi).*sin(theta); Z=R*cos(phi);
[Nx,Ny,Nz]=surfnorm(X,Y,Z);
quiver3(X,Y,Z,Nx,Ny,Nz)

As stated in the title I get the error:"Attempt to execute SCRIPT surfnorm as a function"

even when I run the example code given on the website:

[x,y,z] = cylinder(1:10);
figure
surfnorm(x,y,z)
axis([-12 12 -12 12 -0.1 1])

I get the same error.

Any help or comments would be appreciated, thanks. John

Best Answer

Most likely there is another file named surfnorm that shadows the proper file. Run

which surfnorm -all

to find out

Related Solutions

MATLAB: Shaded surface

St11=100;
Sc11=St11*2/3;
St22=80;
Sc22=St22*2/3;
S=60;
i1 = 0;
r = NaN(101,51);
for phi=0:pi/50:2*pi
    i1 = i1+1;
    i2 = 0;
    if cos(phi)>=0
        X=St11;
    else
        X=Sc11;
    end
    if sin(phi)>=0
        Y=St22;
    else
        Y=Sc22;
    end
    for psi=-pi/2:pi/50:pi/2
        i2=i2+1;
        F=@(r0)(((cos(phi)*cos(psi)*r0)/X)^2-(cos(phi)*cos(psi)*r0*sin(phi)*cos(psi)*r0)/(X^2)+((sin(phi)*cos(psi)*r0)/Y)^2+(r0*sin(psi)/S)^2-1)^2;
        r(i1,i2)=abs(fminsearch(F,0));
    end
end
[psi,phi] = meshgrid(-pi/2:pi/50:pi/2,0:pi/50:2*pi);
x=cos(psi).*cos(phi).*r;
y=cos(psi).*sin(phi).*r;
z=sin(psi).*r;
surf(x,y,z)

MATLAB: How to create an array of vectors corresponding to a particular point

If I understood correctly, you have X, Y, and Z generated by:

R=22; phi=linspace(0,pi,50); theta=linspace(-pi/2,pi/2,50);
[phi,theta]=meshgrid(phi,theta);
X=R*sin(phi).*cos(theta); Y=R*sin(phi).*sin(theta); Z=R*cos(phi);

From that, you want for each triplet (X, Y, Z) to generate all the (X'-X, Y'-Y, Z'-Z) from all the other triplets. This can be easily achieved:

Xv = bsxfun(@minus, X(:), X(:)');
Yv = bsxfun(@minus, Y(:), Y(:)');
Zv = bsxfun(@minus, Z(:), Z(:)');

Each row or column of (Xv, Yv, Zv) is one of the (X,Y,Z) point.

So for example, if you want to see the vectors for the nth (X, Y, Z) triplet:

n = 20; %for example
quiver3(X(:), Y(:), Z(:), Xv(:, n), Yv(:, n), Zv(:, n));

You can even animate it:

for tripletidx = 1:numel(X)
  quiver3(X(:), Y(:), Z(:), Xv(:, tripletidx), Yv(:, tripletidx), Zv(:, tripletidx));
  drawnow;
end

Best Answer

Related Solutions

MATLAB: Shaded surface

MATLAB: How to create an array of vectors corresponding to a particular point

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