I see some tests related to oneAPI fails; it's hard to me to understand why they fail, how should I proceed?

If you have a linux setup it should be pretty straightforward to install oneAPI, and then you can run the pytest. But we can wait to look at the other issues first. Maybe it will clear itself.

Note the utility we have in hls4ml already:
https://github.com/fastmachinelearning/hls4ml/blob/main/hls4ml/utils/fixed_point_utils.py#L139-L141

I wanted to try to install oneAPI myself, so I played with this PR a bit. The issue seems to be that the precision for the parameter of the leaky ReLU is reduced significantly, from typedef ac_fixed<16,6,true> quantizer_param_t; to a one-bit typedef ac_fixed<1,0,false> quantizer_param_t;. Vivado and the other backends seem to be able to handle it, but I'm not sure it makes sense in this case because we have negative slopes here and need it to be signed. The other backends seem to be able to deal with it. But for oneAPI, a signed variable is enforced to have at least two bits:

signed _BitInt must have a bit size of at least 2

So we need to make sure to take this into account when inferring the precision for the parameters.

Hey @nghielme any news on this one?

I'll take a look soon

Please check the logic of the precision setting.

I added a unit test to cover the various options, so I am more confident. It did discover an error in the max setting for unsigned FixedPrecisionType, which I fixed, and am including here, though it's logically independent.