MLM merging

.github/workflows/acceptancetest_madevent.yml

@@ -89,6 +89,7 @@ jobs:
             cd $GITHUB_WORKSPACE
             ./tests/test_manager.py test_group_subprocess -pA -t0 -l INFO
             ./tests/test_manager.py test_group_subprocess_permuted_scale -pA -t0 -l INFO
+            ./tests/test_manager.py test_mlm_pdfrwt_flavour -pA -t0 -l INFO
 
       # ---- acceptancetest_contur ----
       - name: "acceptancetest_contur: run the test"

.github/workflows/acceptancetest_mg7.yml

@@ -608,3 +608,23 @@ jobs:
             # LHAPDF_DATA_PATH (install_lhapdf_pdfset) holds only NNPDF23: unset, these
             # tests find NNPDF40_lo_as_01180 in the heptools data dir via lhapdf-config
             env -u LHAPDF_DATA_PATH ./tests/test_manager.py test_output_mg7_decay_run_card_has_no_cuts test_output_mg7_decay_subprocess_metadata test_color_flow_consistency_mg7 test_systematics_mg7_legacy test_systematics_mixed_order_mg7 test_mg7_reweighting_at_generation test_delphes_mg7 -pA -t0 -l INFO
+
+  acceptancetest_mg7_launcher_cut_names:
+    needs: build_madspace
+    # Unit tests, but they belong here rather than in unittest.yml: they need a
+    # compiled madspace to check that the cut names the mg7 launcher writes are
+    # ones ms.Observable accepts, and the unit jobs have none (they would skip).
+    # No LHAPDF or model files: nothing is generated, the launcher's cut helpers
+    # are called on a stand-in run card. Hence no heptools restore, and no -pA:
+    # these live in the default tests/unit_tests path.
+    runs-on: ubuntu-24.04
+    if: github.event_name == 'push' || github.event.pull_request.head.repo.fork == true
+    steps:
+      - uses: actions/checkout@v4
+      - uses: ./.github/actions/checkout_mg5
+      - uses: ./.github/actions/install_madspace
+      - uses: ./.github/actions/restore-pip-cache
+      - name: test the mg7 launcher writes cut names madspace can build
+        run: |
+            cd $GITHUB_WORKSPACE
+            ./tests/test_manager.py test_every_cut_it_writes_builds_an_observable test_it_tightens_the_jet_pt_and_pair_mass_to_xqcut test_it_drops_the_jet_cone_cuts test_with_the_option_off_it_only_zeroes_cuts_above_xqcut test_it_leaves_an_unmerged_run_alone -t0 -l INFO

Template/LO/SubProcesses/cluster.f

@@ -658,14 +658,20 @@ logical function cluster(p, flavor, ivec)
       enddo
       mt2last=0
       minpt2ij=1.0d37
-c     Map merged flavor particles (PDG=81) to their actual quark flavors
+c     Map the quark legs (and merged 81 legs) to the representative of the
+c     coupling class of this event: FLAVOR(i) is the position of that
+c     representative in the merged quark group, which is its pdg since the
+c     quarks are always merged in pdg order (1,2,...). It is NOT the flavour
+c     of the event (s s~ > z gives 1, c c~ > z gives 2): the flavour
+c     combination (IPSEL) is only drawn after the scales are set, and rewgt
+c     sets the external identities to it after clustering.
       do i=1,nexternal
-         if(flavor(i).ge.1.and.flavor(i).le.5)then
+         if(flavor(i).ge.1.and.flavor(i).le.6)then
                do igraph=1,n_max_cg
                tmppdg=ipdgcl(ishft(1,i-1),igraph,iproc)
-                  if(tmppdg.eq.81.or.(tmppdg.gt.0.and.tmppdg.le.5)) then
+                  if(tmppdg.eq.81.or.(tmppdg.gt.0.and.tmppdg.le.6)) then
                      ipdgcl(ishft(1,i-1),igraph,iproc)=flavor(i)
-                  else if(tmppdg.eq.-81.or.(tmppdg.lt.0.and.tmppdg.ge.-5))then
+                  else if(tmppdg.eq.-81.or.(tmppdg.lt.0.and.tmppdg.ge.-6))then
                      ipdgcl(ishft(1,i-1),igraph,iproc)=-flavor(i)
                   endif
                enddo

Template/LO/SubProcesses/reweight.f

@@ -1504,28 +1504,26 @@ double precision function rewgt(p, flavor, ivec)
          rewgt = 0d0
          return
       endif
-c     Set incoming particle identities
-      ipdgcl(1,igraphs(1),iproc)=idup(1,ipsel,iproc)
-      ipdgcl(2,igraphs(1),iproc)=idup(2,ipsel,iproc)
-      if (btest(mlevel,2)) then
-         write(*,*) 'Set particle identities: ',
-     $        1,ipdgcl(1,igraphs(1),iproc),
-     $        ' and ',
-     $        2,ipdgcl(2,igraphs(1),iproc)
-
-      endif
-
+c     The flavours of this event are those of row IPSEL of leshouche.inc,
+c     as in DSIG. The rows always carry physical pdg codes (merged legs such
+c     as 81 are expanded per flavour), while FLAVOR(:) only holds the
+c     position of the coupling-class representative (see cluster).
+      do j=1,2
+         if(abs(idup(j,ipsel,iproc)).ge.81.and.
+     $        abs(idup(j,ipsel,iproc)).le.83)then
+            write(*,*) 'Error: rewgt: merged particle ',idup(j,ipsel,iproc),
+     $           ' in leshouche.inc (row ',ipsel,'): no physical pdg for',
+     $           ' the PDF of beam ',j
+            stop 1
+         endif
+      enddo
 
       if(ickkw.le.0)then
 c     Store pdf information for systematics studies (initial)
          if(use_syst)then
             do j=1,2
                 n_pdfrw(j,ivec)=1
-                if(abs(ipdgcl(j,igraphs(1),iproc)).eq.81) then
-                   i_pdgpdf(1,j,ivec)=abs(flavor(j))*sign(1,ipdgcl(j,igraphs(1),iproc))
-                else
-                   i_pdgpdf(1,j,ivec)=ipdgcl(j,igraphs(1),iproc)
-                endif
+                i_pdgpdf(1,j,ivec)=idup(j,ipsel,iproc)
                 s_xpdf(1,j,ivec)=xbk(ib(j))
                 s_qpdf(1,j,ivec)=sqrt(q2fact(j))
             enddo
@@ -1545,6 +1543,19 @@ double precision function rewgt(p, flavor, ivec)
       endif
       vec_igraph(ivec) = igraphs(1)  ! save MLM-matched graph for this event
 
+c     Set the identities of the incoming partons and of the jets of the
+c     clustered graph to the flavours of this event: setclscales leaves there
+c     the representative of the coupling class of a grouped subprocess (e.g.
+c     d for s s~ > z, u for c c~ > z), which would otherwise enter the PDF
+c     ratios, the Sudakov factors and the pdfrwt information below. Other
+c     legs are left as set by cluster (nothing below reads their flavour).
+      do i=1,nexternal
+         if(i.le.2.or.isjet(idup(i,ipsel,iproc)))
+     $        ipdgcl(ishft(1,i-1),igraphs(1),iproc)=idup(i,ipsel,iproc)
+         if (btest(mlevel,2))
+     $        write(*,*) 'Set particle identities: ',
+     $        i,ipdgcl(ishft(1,i-1),igraphs(1),iproc)
+      enddo
 
 c     Store pdf information for systematics studies (initial)
 c     need to be done after      setclscales since that one clean the syscalc value
@@ -1608,12 +1619,6 @@ double precision function rewgt(p, flavor, ivec)
 c     Prepare checking for parton vertices
       do i=1,nexternal
          j=ishft(1,i-1)
-c        Set jet identities according to chosen subprocess
-         if(isjet(idup(i,ipsel,iproc)))
-     $        ipdgcl(j,igraphs(1),iproc)=idup(i,ipsel,iproc)
-         if (btest(mlevel,2))
-     $        write(*,*) 'Set particle identities: ',
-     $        i,ipdgcl(j,igraphs(1),iproc)
          if(i.le.2)then
             goodjet(j)=isparton(ipdgcl(j,igraphs(1),iproc))
          elseif(iqjets(i).gt.0) then
@@ -1883,15 +1888,9 @@ double precision function rewgt(p, flavor, ivec)
 c     factor in front of matrix element
          do i=1,2
             if (lpp(IB(i)).ne.0) then
-                if( abs(i_pdgpdf(1,i,ivec)).ne.81)then
                 s_rwfact(ivec)=s_rwfact(ivec)*pdg2pdf(abs(lpp(IB(i))),
      $           i_pdgpdf(1,i,ivec)*sign(1,lpp(IB(i))),IB(i),
      $           s_xpdf(1,i,ivec),s_qpdf(1,i,ivec))
-            else
-                s_rwfact(ivec)=s_rwfact(ivec)*pdg2pdf(abs(lpp(IB(i))),
-     $           abs(flavor(i))*sign(1, i_pdgpdf(1,i,ivec))*sign(1,lpp(IB(i))),IB(i),
-     $           s_xpdf(1,i,ivec),s_qpdf(1,i,ivec))
-            endif
             endif
          enddo
          if (asref.gt.0d0.and.n_qcd(ivec).le.nexternal)then

UpdateNotes.txt

@@ -5,6 +5,10 @@ ANNOUNCEMENT:
    A new LTS (based on the current 3.5.X) is starting now and will act as the stable release for the coming years.
 
 0.3.0 (XX/XX/XX):
+   OM: madevent MLM (ickkw=1) with use_syst: the <pdfrwt> entry of the incoming partons
+       used the flavour class of the grouped subprocess instead of the event's flavour
+       (pdg 1 for s s~, 2 for c c~), so the systematics (PDF and mu_F variations) of every
+       s/c-initiated event were computed with the d/u PDF (up to 9% for mu_F=2 on p p > z).
    OM: madevent LO vector mode (vector_size>1): the good-helicity scan saw a single
        beam orientation per warp, so up to half of p p > z was dropped. With helicity
        recycling, the madevent_forhel scan now runs event by event. Without it