History of `isapprox` in languages

[zdenek_hurak]

Bug with isapprox?

This has nothing to do with the value of eps(0.0). x ≈ 0.0 will always give false for x ≠ 0, because ≈ tests only relative error. If x ≠ 0, then no significant digits of x match 0.0, so the result of x ≈ 0.0 is false. In particular, x ≈ y tests norm(x-y) ≤ sqrt(eps(T))*max(norm(x),norm(y)) with T=typeof(real(x-y)), which tests whether about half of the significant digits match. If you call isapprox(x,y) explicitly, you can pass an atol argument to instead pass an absolute tolerance, i.e. t…