From f43d8b55e63792afbfe5eb83c8f20ce742225eba Mon Sep 17 00:00:00 2001
From: giacomomagni <giac.magni@gmail.com>
Date: Thu, 2 May 2024 14:06:45 +0200
Subject: [PATCH] add a test of fl11/fl2 ratios

---
 .../coefficient_functions/light/kernels.py    |  4 +-
 tests/yadism/cf/test_nc_kernels.py            | 46 +++++++++++++++++++
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/src/yadism/coefficient_functions/light/kernels.py b/src/yadism/coefficient_functions/light/kernels.py
index ef7539dd..71317093 100644
--- a/src/yadism/coefficient_functions/light/kernels.py
+++ b/src/yadism/coefficient_functions/light/kernels.py
@@ -94,7 +94,7 @@ def generate(esf, nf):
         quark_fl11 = pcs.QuarkFL11(esf, nf)
         weights_fl11 = nc_fl11_weights(esf.info.coupling_constants, esf.Q2, nf)
         ns_fl11 = kernels.Kernel(
-            weights_fl11["ns"],
+            weights_fl11["q"],
             quark_fl11,
         )
         g_fl11 = kernels.Kernel(weights_fl11["g"], gluon_fl11)
@@ -203,4 +203,4 @@ def nc_fl11_weights(coupling_constants, Q2, nf, skip_heavylight=False):
     # NOTE: since here we are implementing the plain coupling
     # Q1 * Tr[Q2] / nf, we have not decomposed the quark sector
     # into singlet and non singlet for this class of diagrams
-    return {"ns": quark_partons, "g": {21: ch_av}}
+    return {"q": quark_partons, "g": {21: ch_av}}
diff --git a/tests/yadism/cf/test_nc_kernels.py b/tests/yadism/cf/test_nc_kernels.py
index fb4aa7aa..7113ca5a 100644
--- a/tests/yadism/cf/test_nc_kernels.py
+++ b/tests/yadism/cf/test_nc_kernels.py
@@ -3,6 +3,7 @@
 from eko.matchings import Atlas
 
 from yadism import observable_name as on
+from yadism.coefficient_functions import coupling_constants as cc
 from yadism.coefficient_functions.asy import kernels as aker
 from yadism.coefficient_functions.heavy import kernels as hker
 from yadism.coefficient_functions.intrinsic import kernels as iker
@@ -93,6 +94,51 @@ def test_generate_heavy():
         check(ps, w)
 
 
+def test_nc_fl11_weights():
+    # Test the the flavor decomposition of the fl11 diagrams is the same as we get from
+    # the yadism implementation
+    th_d = dict(
+        SIN2TW=0.5,
+        MZ=80,
+        CKM="0.97428 0.22530 0.003470 0.22520 0.97345 0.041000 0.00862 0.04030 0.999152",
+    )
+    obs_d = dict(
+        projectilePID=11,
+        PolarizationDIS=0.0,
+        prDIS="EM",
+        PropagatorCorrection=0,
+        NCPositivityCharge=None,
+    )
+    coupl_const = cc.CouplingConstants.from_dict(th_d, obs_d)
+
+    Q2 = 1.0
+    mean_e = 0
+    mean_e2 = 0
+    for nf in range(1, 7):
+        fl11_weights = lker.nc_fl11_weights(coupl_const, Q2, nf)
+        fl2_weights = lker.nc_weights(coupl_const, Q2, nf, False)
+
+        # build rations to fl2
+        mean_e += coupl_const.electric_charge[nf]
+        mean_e2 += coupl_const.electric_charge[nf] ** 2
+        w3 = mean_e**2 / nf / mean_e2
+        w2 = 3 * mean_e / nf
+
+        # test gluon coupling
+        np.testing.assert_allclose(fl11_weights["g"][21], fl2_weights["g"][21] * w3)
+
+        # test the quark sector
+        # now need to sum over all the pids
+        q = 0
+        ns = 0
+        ps = 0
+        for pid, c in fl11_weights["q"].items():
+            ns += w2 * fl2_weights["ns"][pid]
+            ps += (w3 - w2) * fl2_weights["s"][pid]
+            q += c
+        np.testing.assert_allclose(ns + ps, q)
+
+
 @pytest.mark.skip
 def test_generate_light_fonll_diff_pc():
     esf = MockESF("F2_light", 0.1, 10)