Merge pull request #48 from N3PDF/physics/alpha_s_NLO

Alpha_s at NLO for Yadism

.github/workflows/pythonapp.yml

@@ -6,13 +6,18 @@ jobs:
   build:
 
     runs-on: ubuntu-latest
+    strategy:
+#      max-parallel: 2
+      matrix:
+        python-version: [3.7, 3.8]
+      fail-fast: false
 
     steps:
     - uses: actions/checkout@v2
-    - name: Set up Python 3.8
+    - name: Set up Python ${{ matrix.python-version }} 🐍
       uses: actions/setup-python@v1
       with:
-        python-version: 3.8
+        python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
         sudo apt-get install -y libgsl-dev

doc/source/Theory/pQCD.txt

@@ -14,6 +14,8 @@ We use perturbative QCD with the running coupling
 
 Our main reference is :cite:`Herzog:2017ohr`.
 
+The matching conditions are given in :cite:`Chetyrkin:1997sg`.
+
 Implementation: :class:`~eko.strong_coupling.StrongCoupling`
 
 Splitting Functions

doc/source/refs.bib

@@ -122,4 +122,16 @@ @article{Vogt:2004ns
     title = "{Efficient evolution of unpolarized and polarized parton distributions with QCD-PEGASUS}",
     volume = "170",
     year = "2005"
+}
+@article{Chetyrkin:1997sg,
+    author = "Chetyrkin, K.G. and Kniehl, Bernd A. and Steinhauser, M.",
+    title = "{Strong coupling constant with flavor thresholds at four loops in the MS scheme}",
+    eprint = "hep-ph/9706430",
+    archivePrefix = "arXiv",
+    reportNumber = "MPI-PHT-97-025",
+    doi = "10.1103/PhysRevLett.79.2184",
+    journal = "Phys. Rev. Lett.",
+    volume = "79",
+    pages = "2184--2187",
+    year = "1997"
 }

setup.py

@@ -2,7 +2,7 @@
 from setuptools import setup, find_packages
 
 setup(name='eko',
-      version='0.0.1',
+      version='0.2.0',
       description='Evolution Kernel Operator',
       author = 'S.Carrazza, J.Cruz-Martinez, F. Hekhorn',
       author_email='stefano.carrazza@cern.ch',
@@ -36,5 +36,5 @@
           "cffi>1.0.0"
       ],
       cffi_modules=["src/cfunctions/digamma.py:ffibuilder"],
-      python_requires='>=3.8'
+      python_requires='>=3.7'
 )

src/eko/evolution_operator.py

@@ -356,6 +356,8 @@ def __mul__(self, other):
                 p : PhysicalOperator
                     self * other
         """
+        if not isinstance(other, PhysicalOperator):
+            raise ValueError("Can only multiply with another PhysicalOperator")
         # prepare paths
         instructions = {}
         for my_op in self.op_members.values():
@@ -377,7 +379,7 @@ def __mul__(self, other):
         new_ops = {}
         for key, paths in instructions.items():
             new_ops[key] = OperatorMember.join(op_to_compose, paths)
-        return PhysicalOperator(new_ops, self.q2_final)
+        return self.__class__(new_ops, self.q2_final)
 
     def get_raw_operators(self):
         """

src/eko/kernel_generation.py

@@ -199,12 +199,12 @@ def njit(self, function):
             Parameters
             ---------
                 function : callable or list(callable)
-                    input (list of) function
+                    input (list of) callable(s)
 
             Returns
             -------
                 function : callable or list(callable)
-                    compiled (list of) function
+                    compiled (list of) callable(s)
         """
         if isinstance(function, abc.Iterable):
             return [self.njit(f) for f in function]

src/eko/output.py

@@ -34,7 +34,7 @@ def apply_pdf(self, input_pdfs, targetgrid=None):
             Returns
             ---------
                 out_grid : dict
-                    output PDFs and their associated errors for the computed q2_grid
+                    output PDFs and their associated errors for the computed Q2grid
         """
         # TODO rotation from the evolution basis to flavor basis? if yes, here!
         # turn input_pdfs into lists
@@ -47,7 +47,7 @@ def apply_pdf(self, input_pdfs, targetgrid=None):
 
         # build output
         out_grid = {}
-        for q2 in self["q2_grid"]:
+        for q2 in self["Q2grid"]:
             pdfs, errs = self.get_op(q2).apply_pdf(input_lists)
             out_grid[q2] = {"pdfs": pdfs, "errors": errs}
 
@@ -85,7 +85,7 @@ def get_raw(self):
         """
         # prepare output dict
         out = {
-            "q2_grid": {},
+            "Q2grid": {},
         }
         # dump raw elements
         for f in ["polynomial_degree", "is_log_interpolation", "q2_ref"]:
@@ -94,8 +94,8 @@ def get_raw(self):
         for k in ["xgrid"]:
             out[k] = self[k].tolist()
         # make operators raw
-        for q2 in self["q2_grid"]:
-            out["q2_grid"][q2] = self.get_op(q2).get_raw_operators()
+        for q2 in self["Q2grid"]:
+            out["Q2grid"][q2] = self.get_op(q2).get_raw_operators()
         return out
 
     def dump_yaml(self, stream=None):
@@ -113,6 +113,7 @@ def dump_yaml(self, stream=None):
                     result of dump(output, stream), i.e. a string, if no stream is given or
                     Null, if self is written sucessfully to stream
         """
+        # TODO explicitly silence yaml
         out = self.get_raw()
         return yaml.dump(out, stream)
 
@@ -187,10 +188,10 @@ def get_op(self, q2):
                     corresponding Operator
         """
         # check existence
-        if q2 not in self["q2_grid"]:
+        if q2 not in self["Q2grid"]:
             raise KeyError(f"q2={q2} not in grid")
         # compose
-        ops = self["q2_grid"][q2]
+        ops = self["Q2grid"][q2]
         op_members = {}
         for name in ops["operators"]:
             op_members[name] = OperatorMember(
@@ -225,16 +226,16 @@ def concat(self, other):
             raise ValueError(f"'xgrid' of the two factors does not match")
         # check matching
         mid_scale = self["q2_ref"]
-        if not mid_scale in other["q2_grid"]:
+        if not mid_scale in other["Q2grid"]:
             raise ValueError("Operators can not be joined")
         # prepare output
         other_op = other.get_op(mid_scale)
         out = copy.deepcopy(self)
         out["q2_ref"] = other["q2_ref"]
-        for q2 in self["q2_grid"]:
+        for q2 in self["Q2grid"]:
             # multiply operators
             me = self.get_op(q2)
             prod = me * other_op
-            out["q2_grid"][q2] = prod.get_raw_operators()
+            out["Q2grid"][q2] = prod.get_raw_operators()
 
         return out