| 1 | = Clustering/reweighting page |
| 2 | |
| 3 | == OBJECT MEANING |
| 4 | |
| 5 | *** WARNING *** THIS IS ONLY MY CURRENT UNDERSTANDING OF JOHAN's CODE. IT MIGHT BE ... WRONG |
| 6 | |
| 7 | === idacl(NEXTERNAL,2) |
| 8 | |
| 9 | Returns an id identifying uniquely a particles: |
| 10 | For an external particles the id is $2^(N-1)$. For a propagator this is the sum of the id of all particles in which |
| 11 | this particles decays. |
| 12 | |
| 13 | The first index indicates the various merging steps and the second index which particles is merging with wich ones. |
| 14 | |
| 15 | === icluster(4,nexternal) |
| 16 | |
| 17 | Not clear, the code comment says: |
| 18 | c variable for LH output of clustering info (R,E,S,I) |
| 19 | but no idea what those four letter means... |
| 20 | |
| 21 | === imocl(NEXTERNAL) |
| 22 | |
| 23 | Returns an id identifying uniquely a particles associated to the merging of that level. |
| 24 | we therefore have idacl(I,1) + idacl(I,2) -> imocl(I) |
| 25 | |
| 26 | === iproc |
| 27 | |
| 28 | I guess that's refer to the which matrix.f we have to consider for the graph. |
| 29 | |
| 30 | === igraphs(0:n_max_cg) |
| 31 | |
| 32 | The first component is special (syze for the specific process?) |
| 33 | I guess that this is the link to the various diagrams (in the various matrix.f) for the specific config. |
| 34 | |
| 35 | === ipart(2,n_max_cl) |
| 36 | |
| 37 | ipart gives the external particle number corresponding to the present |
| 38 | quark or gluon line. |
| 39 | For t-channel lines, ipart(1) contains the connected beam. |
| 40 | For s-channel lines, it depends if it is quark or gluon line: |
| 41 | For quark lines, ipart(2) is 0 and ipart(1) connects to the corresponding |
| 42 | final-state quark. For gluons, if it splits into two gluons, |
| 43 | it connects to the hardest gluon. If it splits into qqbar, it ipart(1) is |
| 44 | the hardest and ipart(2) is the softest. |
| 45 | |
| 46 | === other comment/variable |
| 47 | 1. jfirst(2) is first parton splitting on this side |
| 48 | 1. jlast(2) is last parton on this side |
| 49 | 1. jcentral(2) is the central scale vertex on this side |
| 50 | 1. qcdline(2) gives whether this IS line is QCD |
| 51 | 1. partonline(2) gives whether this IS line is parton (start out true for any QCD) |
| 52 | 1. goodjet(n_max_cl) gives whether this cluster line is considered a jet |
| 53 | 1. jcode helps keep track of how many QCD/non-QCD flips we have gone through |
| 54 | 1. increasecode gives whether we should increase jcode at next vertex |
| 55 | |
| 56 | |
| 57 | === clustering technique |
| 58 | |
| 59 | 1. The last step of the clustering is (always?) the one with ipart(1, X) and ipart(2,X) are [1,2]! |
| 60 | 1. |