Does matlab have a function that says "If zero is near?

Asked by Muhendisleksi on 12 Aug 2017

Latest activity Commented on by Walter Roberson on 12 Aug 2017

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I need a command that checks that the number is near zero.

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Jan on 12 Aug 2017

Note that "near zero" is not well defined. Is 0.00001 near zeros or only 1e-100?

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Answer by Star Strider on 12 Aug 2017

There is not built-in MATLAB function for that.

It is possible to create one easily enough:

nearZero = @(x,tol) abs(x) < tol;                       % Test If ‘x’ Is Within ‘tol’ OF Zero
tol = 0.5;
x = rand(1,6) .* (-2:3);
Test = [x; nearZero(x,tol)]
Test =
     -0.87571    -0.057386            0     0.090743       1.0487     0.082315
            0            1            1            1            0            1

2 Comments

John D'Errico on 12 Aug 2017

+1. Or you can make it an m-file, if this is something you wish to keep around forever because you use it often. To be honest, I think most of us don't bother, just writing the test like (abs(x)<tol) in our sleep as we need it. That is why there is no function to do this explicitly in MATLAB.

Walter Roberson on 12 Aug 2017

ismembertol can also be used for this purpose

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