How to create array or table using for loop?
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Hello, I want to create a table or an array using for loop. What I want to do is something like running a function using the iteration numbers and i want to pring out both iteration numbers and the function in a table form or an array. For example:
for x = 1:64
for y = 1:64
for z = 1:64
f = 2*x + 2*y + z^2 (it's just an example, but some function like this)
end
end
end
I want to calculate the value of f at each iteration and print out all the values of x, y, z and the function f values either in a table or in an array like this
x y z f
1 1 1 5
2 2 2 12
3 3 3 21
4 4 4 32
and so on for all of them. How can i do that?
1 Comment
David Hill
on 12 Sep 2019
You likely will not need any loops at all. If you use the loops (as above), then you could have a matrix (F) that you should preallocate.
F=zeros(64^3,4);
count=1;
for x = 1:64
for y = 1:64
for z = 1:64
f = 2*x + 2*y + z^2 (it's just an example, but some function like this)
F(count,:)=[x,y,z,f];
count=count;
end
end
end
Accepted Answer
Walter Roberson
on 12 Sep 2019
f = zeros(64, 64, 64);
fidx = zeros(64, 64, 64, 3);
for x = 1:64
for y = 1:64
for z = 1:64
f(x,y,z) = 2*x + 2*y + z^2; %(it's just an example, but some function like this)
fidx(x,y,z,:) = [x, y, z];
end
end
end
x = reshape(fidx(:,:,:,1), [], 1);
y = reshape(fidx(:,:,:,2), [], 1);
z = reshape(fidx(:,:,:,3), [], 1);
f = f(:);
results = table(x, y, z, f);
However, you would be more likely to use a different approach:
[x, y, z] = ndgrid(1:64, 1:64, 1:64);
f = 2*x + 2*y + z.^2;
x = x(:);
y = y(:);
z = z(:);
f = f(:);
results = table(x, y, z, f);
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