Khalil Ouardini

Adding interaction terms to the design matrix

21

This PR has several purposes: - it leverages [formulaic]((https://matthewwardrop.github.io/formulaic/guides/contrasts/#treatment-aka-dummy)) to allow using interaction terms of the form `a:b:...:z`for `design_factors` and formulas based on a combination of single design factors and...

**Describe the bug** the expanded argument in `utils.build_design_matrix` is not used **Additional context** related to [PR#181](https://github.com/owkin/PyDESeq2/pull/181)

**Is your feature request related to a problem? Please describe.** Not clear how the user can include interaction terms in the design matrix. **Describe the solution you'd like** A short...

**Is your feature request related to a problem? Please describe.** `utils.py` file is hard to read and modify. **Describe the solution you'd like** seperate `utils` function by theme in different...