Script that modifies MATRIX y_ttbar grids

[Radonirinaunimi]

In order to perform fewer runs with MATRIX, predictions for $\pm y_{t \bar{t}}$ can be extracted from $|y_{t \bar{t}}|$. The following script does so by performing the following operations:

• extract the negative rapidity bins and divide the observable predictions by 2
• extract the positive rapidity bins and divide the observable predictions by 2
• re-order the negative rapidity bin predictions to conform with the commondata
• merge the two Grids such that predictions are given by $\left\lbrace -y_{t \bar{t}}, +y_{t \bar{t}} \right\rbrace$

TODO:

• run pre-commit hooks
• add checks/tests
• support different versions of PineAPPL
• add as pinefarm module (?) - deprecates 3rd point

[jacoterh]

The pre-commit complains?

[felixhekhorn]

Don't add it here - regardless if it will (already) become a proper pinefarm module or no. This lives just as well in the place where it belongs: tests/

[Radonirinaunimi]

Moving the tests part into tests/ is indeed a good idea regardless. Right now I don't have any time at all but will do so as soon as I have some.

[felixhekhorn]

Do you want to test the CLI as well? since there are a series of commands

[Radonirinaunimi]

Yes, that'd be added along with an additional test for modify_grids.

[jacoterh]

Hi @Radonirinaunimi, this works great! One comment, while using this script I noticed that the normalisation given by norm is off by a factor 2, which is probably a result of dividing all predictions by 2.

pineappl read --bins <grid.pineappl.lz.4>

gives

b top pair rapidity        norm       
-+--------+--------+------------------
0     -2.5     -1.3                2.4
1     -1.3     -0.9                0.8
2     -0.9     -0.6 0.6000000000000001
3     -0.6     -0.3                0.6
4     -0.3       -0                0.6
5        0      0.3                0.6
6      0.3      0.6                0.6
7      0.6      0.9 0.6000000000000001
8      0.9      1.3                0.8
9      1.3      2.5                2.4

and as you can see norm does not match the bin width. Also there is a minus sign in front of the 0 in bin number 4. Do you think the script can be modified to fix this?