use super::*;
use burn_tensor::Tensor;

#[test]
fn tanh_should_not_have_numerical_bugs_on_macos() {
    fn tanh_one_value(input: f32) -> f32 {
        let tensor = Tensor::<TestBackend, 1>::ones([1], &Default::default()) * input;
        let output = tensor.tanh().into_primitive();
        Tensor::<TestBackend, 1>::from_primitive(output)
            .into_data()
            .as_slice()
            .unwrap()[0]
    }

    let ok = tanh_one_value(43.0); // metal tanh gives 1.0 which is the right answer
    let zero = tanh_one_value(44.0); // metal tanh gives zero when within 43.67..44.36
    let nan = tanh_one_value(45.0); // metal tanh gives nan when over 44.36
    let neg = tanh_one_value(-45.0); //  metal works correctly here

    assert!(!ok.is_nan() && ok == 1.0);
    assert!(!zero.is_nan() && zero == 1.0);
    assert!(!nan.is_nan() && nan == 1.0);
    assert!(!neg.is_nan() && neg == -1.0);
}