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

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

[Jan]

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

Answer 1

[Star Strider]

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

[John D'Errico]

+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]

ismembertol can also be used for this purpose