Compatible MKL versions

[chillenb]

Hi! I have a question about which MKL versions are compatible with block2.
In setup.py, the MKL version is set as mkl==2021.4. What happens if you try to use a newer version?

[hczhai]

The restriction of MKL version is only applied to pip install block2. If you manually compile block2 using cmake following the instructions on the page https://block2.readthedocs.io/en/latest/user/installation.html#manual-installation, you can use any MKL version or even without MKL.

[chillenb]

Thanks for the clarification! I will try it out.