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

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Muhendisleksi 2017-8-12

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评论： Walter Roberson 2017-8-12

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

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Jan 2017-8-12

编辑：Jan 2017-8-12

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

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Answer 1

Star Strider 2017-8-12

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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

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John D'Errico 2017-8-12

+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.