Diagonal cross section of function z(x,y) for x=y

I have a function as z(x,y) and I want to plot z(x,y) vs x=y. How can I plot it? Cross section of function z(x,y) for x=y

I will be glad if you help

[DGM]

How is the function defined? is it a MATAB function? Is this using symbolic tools? Or is it just a 2D numeric array?

Answer 1

[Leia]

t = X-Y;

er = 1e-10;

mask = abs(t) < er;

X2 = X(mask);

Y2 = Y(mask);

Z2 = V(mask);

plot(X2,Y2,Z2)

plot(X2,Z2)

Answer 2

[Matt J]

fcn=@(t) arrayfun(@(x) z(x,x), t);

fplot(fcn)

[Matt J]

As an example,

z=@(x,y) x.^2+2*x*y + y.^2;

fcn=@(t) arrayfun(@(x) z(x,x), t);

fplot(fcn,[-1,1])

Answer 3

[Simon Chan]

Easier to assign some values where x=y in function meshgrid as follows:

If the assigned values for x and y are different, then the following does not work.

x = -10:0.1:10;
y = -10:0.1:10;
A = 1;                              % Assume A=1
[X, Y] = meshgrid(x, y); 
D  = 4; T = 0; K=1;
for p = 0:(D-1)
    alpha  = 2*pi*p/D;  
    T= T + exp(1i*K*(cos(alpha)*X+sin(alpha)*Y));
end
Z = A*abs(T/D).^2;
plot(X(X==Y),Z(X==Y))