Basic function to find value

Question

Mughees Asif 2019-3-18

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回答： Walter Roberson 2019-3-18

Hi, I have the following function which should consume a row vector and return a value of 1, if non of the elements are 0 in the vector. If an element is 0, it should return 0.

AllNonZero(a);
function AllNonZero(a)     
if all(a ~= 0)
    true(1)
else
    false(0)
end
end 

I am trying to call this function from the command window as,

AllNonZero([random_vector])

where the random_vector is any arbitrary vector. However, I get the following error,

Attempt to execute SCRIPT AllNonZero as a function:
C:\Users\fluxw\OneDrive\Documents\MATLAB\AllNonZero.m

When I run it simply as "AllNonZero" I get an output of,

AllNonZero
ans =
  0×0 empty logical array
  

I am a beginner so any advice would be helpful. Thank you.

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Answer 1

Image Analyst 2019-3-18

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Use any() instead of all()

% Returns 0 if any elmeents are zero, 1 otherwise.
function tf = AllNonZero(vec)     
tf = ~any(vec == 0)

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Answer 2

Walter Roberson 2019-3-18

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true() and false() are functions that accept sizes. true(1) means the same as true(1,1) which gives you a 1 x 1 array of values all of which contain true. false(0) means the same as false(0,0) which gives you a 0 x 0 (empty) array of values that would all be false if there were any elements there. You should just be using true and false not those followed by a size.

You should remove the

AllNonZero(a);

call that you have at the top of your file.