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

### Muhendisleksi (view profile)

on 12 Aug 2017
Latest activity Commented on by Walter Roberson

### Walter Roberson (view profile)

on 12 Aug 2017
I need a command that checks that the number is near zero.

Jan

### Jan (view profile)

on 12 Aug 2017
Note that "near zero" is not well defined. Is 0.00001 near zeros or only 1e-100?

### Star Strider (view profile)

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

John D'Errico

### John D'Errico (view profile)

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

### Walter Roberson (view profile)

on 12 Aug 2017
ismembertol can also be used for this purpose