Config.epsilon doesn't seem to be working

[dvd101x]

On the current version V12.3.0, config.epsilon doesn't seem to be working.

The expected behavior is:

epsilon. The minimum relative difference used to test equality between two compared values. This value is used by all relational functions. Default value is 1e-12.

equal(0, 1e-13)    # false but should be true
equal(0, 1e-14)    # false but should be true
equal(0, 1e-15)    # false but should be true
equal(0, 1e-16)    # true

config({epsilon: 1e-3})  # {"epsilon": 0.001, "matrix": "Matrix", ...
equal(0, 1e-4)     # false but should be true
equal(0, 1e-6)     # false but should be true
equal(0, 1e-7)     # false but should be true
equal(0, 1e-15)    # false but should be true
equal(0, 1e-16)    # true

Regardless of config.epsilon, it's as if the value of epsilon was 2.220446049250313e-16

equal(0, 2.220446049250313e-16)     # true
equal(0, 2.220446049250314e-16)     # false
smallerEq(2.220446049250313e-16, 0) # true
smallerEq(2.220446049250314e-16, 0) # false

And it seems to be coming from this line of code.

mathjs/src/utils/number.js

Line 596 in a131845

export const DBL_EPSILON = Number.EPSILON || 2.2204460492503130808472633361816E-16

I have not tested all relational functions but is seems consistent on the few I have tested.

Maybe it's also related to #3100

(Also tested V9.5.2, V10.6.4 and V11.12.0 with the same results)

[josdejong]

The nearly-equal comparison uses a relative equality. Comparing against zero is a special case.

Does this help: https://mathjs.org/docs/datatypes/numbers.html#equality?

[dvd101x]

Yes, thank you very much.

My bad, didn't notice that comparing against 0 was a special case.