How can I check if two variables return the same value?
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I defined two variables which are supposed to return the same numerical value through two different formulas.
I want to make sure that the two variables indeed return the same value. Let's call the two variables A and B.
If in the Editor I input
A
B
the values returned are exactly the same. However, if I input
A == B
I visualize
ans =
logical
0
while I expect "1".
What am I doing wrong? If I input
diff([A, B]) I am returned zero.
Thanks.
2 个评论
Stephen23
2022-2-21
"the values returned are exactly the same"
Most likely the values are not exactly the same, or contain NaNs. But because you did not give us the values, we cannot check this. Please upload both values in one mat file by clicking the paperclip button.
Torsten
2022-2-21
Did you choose
format long
to display the numbers ?
There might be a difference between them due to floating point arithmetic.
回答（1 个）
If A and B are floatinng point numbers (which are mostly), then you cannot use A == B. In this case to comapre them fix a tolerance value and check for the absolute difference.
tol = 10^-5 ;
abs(A-B)<tol
You may read more here: https://matlabgeeks.com/tips-tutorials/floating-point-comparisons-in-matlab/
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