# Evaluating 2D function on 2D grid without using "for" loops

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Luqman Saleem on 21 Aug 2020
Commented: Sara Boznik on 22 Aug 2020
I have a function f(x,y) and I want to evaluate it on x,y grid. For example,
f = @(x,y) x^2+y^2;
x = 1:10;
y = 1:5;
%one way to do it is using for loops.
for x=1:10
for y=1:5
result(x,y) = f(x,y);
end
end
Is there any way do it without using "for" loops?
Stephen23 on 22 Aug 2020
"Is there any way do it without using "for" loops?"
Why do you want to avoid for loops? Contrary to what some beignners think, (well-written) for loops are not slow.
Is result preallocated before the loops?

Sara Boznik on 21 Aug 2020
f = @(x,y) x.^2+y.^2;
x = 1:10;
y = 1:5;
[X,Y] = meshgrid(x,y);
meshc(X, Y, f(X,Y))
grid on
You can try that.
Best of luck.
Luqman Saleem on 21 Aug 2020
Actually, the original function is very large and I will have to put (.) in front of all "^" or "*" operators. It also involves matrix multiplication, so, it will just be very messy if I try to put ".". Is there any way to avoid doing it?
Sara Boznik on 22 Aug 2020
Sorry, I do not know faster way

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