Kinematic coverage for polarized datasets

[scarlehoff]

While in principle a process type was added, the implementation of the (unpolarized) DIS datasets are slightly different from the polarized ones. Mainly because of the missing kinematic variables (DIS still use k1/k2/k3).

nnpdf/validphys2/src/validphys/process_options.py

Line 124 in 6691f56

def _dis_xq2map(kin_info):

It might be enough to modify this function to

    x = kin_info.get_one_of("k1", _Vars.x)
    q = kin_info.get_one_of("k2", _Vars.Q)
    return x, q * q

but it requires some testing to make sure that the results are as expected.

[Radonirinaunimi]

I have already looked into this and fixed it before to generate kinematic plots for a talk (slack-slides). But I couldn't find anymore nor remember what has done back then.

But your suggestion (with a very tiny tweak) works in #2109 and gives the same result as back then (report).