First version of SmeftFR converter

setup.py

@@ -22,7 +22,7 @@
                 ]
       },
       install_requires=['pyyaml', 'ckmutil>=0.3.2', 'pandas',
-                        'wilson'],
+                        'wilson', 'pylha>=0.4'],
       extras_require={
             'testing': ['nose'],
       },
@@ -33,6 +33,7 @@
             'wcxf2dsixtools = wcxf.cli:wcxf2dsixtools',
             'dsixtools2wcxf = wcxf.cli:dsixtools2wcxf',
             'wcxf2smeftsim = wcxf.cli:smeftsim',
+            'wcxf2smeftfr = wcxf.cli:wcxf2smeftfr',
         ]
       },
     )

wcxf/cli.py

@@ -222,3 +222,22 @@ def dsixtools2wcxf():
     args = parser.parse_args()
     dsixtools.dsixtools2wcxf(tuple(f for f in args.FILE), stream=args.output)
     return 0
+
+
+def wcxf2smeftfr():
+    from wcxf.converters import smeftfr
+    parser = argparse.ArgumentParser(description="""Command line script to convert a WCxf file to a MadGraph param_card file for SmeftFR.""",
+                                     formatter_class=argparse.RawTextHelpFormatter)
+    parser.add_argument("FILE", nargs='?', help="Input file. If \"-\", read from standard input",
+                        type=argparse.FileType('r'), default=sys.stdin)
+    parser.add_argument("--card", required=True, help="Path to a SmeftFR parameter card necessary to define the output format",
+                        type=argparse.FileType('r'))
+    parser.add_argument("--output", nargs='?', help="Output file. If absent, print to standard output",
+                        type=argparse.FileType('w'), default=sys.stdout)
+    args = parser.parse_args()
+    card = pylha.load(args.card, comments=True)
+    info_dict = smeftfr.analyze_smeftfr_param_card(card)
+    wc = wcxf.WC.load(args.FILE)
+    wc.validate()
+    smeftfr.wcxf2smeftfr(wc, info_dict, card, stream=args.output)
+    return 0

wcxf/converters/smeftfr.py

@@ -0,0 +1,96 @@
+import pylha
+import json
+import pkgutil
+import re
+from wilson.util import smeftutil
+
+
+def format_smeftfr(s):
+    """Recast the string representation of SMEFT WCs used in SmeftFR's line
+    comments to WCxf Warsaw-basis format."""
+    t = s[1:]  # drop 'C'
+    t = t.replace('w__2', 'W')  # special case: 'W' Wilson coefficient
+    t = re.sub(r'(\w)(\d)x(\d)x(\d)x(\d)', r'\1_\2\3\4\5', t)  # 4-fermion
+    t = re.sub(r'(\w)(\d)x(\d)', r'\1_\2\3', t)  # 2-fermion
+    # DeltaL=1
+    t = t.replace('vv_', 'llphiphi_')
+    # DeltaB=1
+    t = t.replace('duq_', 'duql_')
+    t = t.replace('qqu_', 'qque_')
+    t = t.replace('qqq_', 'qqql_')
+    t = t.replace('duu_', 'duue_')
+    return t
+
+
+def analyze_smeftfr_param_card(card_dict):
+    """Read a `param_card_default.dat` generated by SmeftFR and return a
+    dictionary mapping the LHA blocks and indices to WCxf Wilson coefficients.
+
+    The input is expected to be a dictionary as returned by `pylha.load`.
+
+    This is needed for the generation of custom parameter cards."""
+    d = {}
+    for bname, block in card_dict['BLOCK'].items():
+        d[bname] = []
+        for line in block['values']:
+            comment = line[-1]
+            if comment[2] != 'C':
+                continue
+            value = line[-2]
+            index = line[:-2]
+            coeff = format_smeftfr(comment.strip()[2:])
+            d[bname].append({'index': index, 'coeff': coeff, 'comment': comment})
+        if not d[bname]:  # remove empty entries
+            del d[bname]
+    return d
+
+
+def wcxf2smeftfr_dict(wc, info_dict):
+    """Take a WC instance and turn it into a dictionary suitable for producing
+    and LHA file for SmeftFR using pylha."""
+    # go from flat dict to dict of arrays, symmetrizing them
+    C = smeftutil.wcxf2arrays_symmetrized(wc.dict)
+    # go back to flat dict but keeping non-redundant WCs an symm. fac.s
+    d = smeftutil.arrays2wcxf(C)
+    # rearrange to dict in right format for SmeftFR
+    card = {}
+    for block_name, block in info_dict.items():
+        card[block_name] = {'values': []}
+        for info in block:
+            line = [*info['index'], d[info['coeff']].real, info['comment']]
+            card[block_name]['values'].append(line)
+    return card
+
+
+def wcxf2smeftfr(wc, info_dict, card_dict, stream):
+    """Take a WC instance and dump it into an LHA file (or return as string)
+    in a format suitable for use as `param_card.dat` file for MadGraph
+    with SmeftFR.
+
+    Parameters:
+
+    - wc: `WC` instance
+    - info_dict: dictionary as returned by `analyze_smeftfr_param_card`
+    - strem: output file-like object
+    """
+    if (wc.eft, wc.basis) == ('SMEFT', 'Warsaw mass'):
+        wc_m = wc
+    else:
+        if wc.eft != 'SMEFT':
+            raise ValueError("wcxf2smeftfr only support SMEFT Wilson coefficients")
+        else:
+            try:
+                wc_m = wc.translate('Warsaw mass')
+            except ValueError:
+                raise ValueError("wcxf2smeftfr requires a basis that can be translated to the Warsaw mass basis")
+    card = {}
+    card['DECAY'] = card_dict['DECAY'].copy()
+    card['BLOCK'] = wcxf2smeftfr_dict(wc_m, info_dict)
+    for name, block in card_dict['BLOCK'].items():
+        if name not in card['BLOCK']:
+            card['BLOCK'][name] = card_dict['BLOCK'][name].copy()
+        # else:
+        #     for k, v in block.items():
+        #         if k not in card['BLOCK'][name]:
+        #             card['BLOCK'][name][k] = v
+    return pylha.dump(card, fmt='lha', stream=stream)