pyslha.py

Sat, 21 Aug 2010 16:13:50 +0100

author
Andy Buckley <andy@insectnation.org>
date
Sat, 21 Aug 2010 16:13:50 +0100
changeset 30
2e20779d3e6e
parent 29
764234670c09
child 31
7d41d901fdd0
permissions
-rw-r--r--

Writing out mostly working: need a bit of thought again re. ALPHA

andy@1 1 #! /usr/bin/env python
andy@1 2
andy@8 3 """\
andy@8 4 A simple but flexible parser of SUSY Les Houches Accord (SLHA) model and decay files.
andy@25 5
andy@30 6 TODO: Fix treatment of single-entry blocks, e.g. ALPHA
andy@8 7 """
andy@8 8
andy@8 9 from __future__ import with_statement
andy@26 10
andy@8 11 __author__ = "Andy Buckley <andy.buckley@cern.ch"
andy@30 12 __version__ = "0.2.0"
andy@8 13
andy@1 14 import re
andy@1 15
andy@4 16 def _autotype(var):
andy@30 17 """Automatically convert strings to numerical types if possible."""
andy@30 18 if type(var) is not str:
andy@4 19 return var
andy@4 20 if var.isdigit():
andy@4 21 return int(var)
andy@4 22 try:
andy@4 23 f = float(var)
andy@4 24 return f
andy@4 25 except ValueError:
andy@4 26 return var
andy@4 27
andy@30 28 def _autostr(var):
andy@30 29 """Automatically numerical types to the right sort of string."""
andy@30 30 if type(var) is float:
andy@30 31 return "%e" % var
andy@30 32 return str(var)
andy@30 33
andy@30 34
andy@4 35
andy@12 36 class Block(object):
andy@8 37 """
andy@8 38 Object representation of any BLOCK elements read from the SLHA file. Blocks
andy@8 39 have a name, may have an associated Q value, and then a collection of data
andy@8 40 entries, stored as a recursive dictionary. Types in the dictionary are
andy@8 41 numeric (int or float) when a cast from the string in the file has been
andy@8 42 possible.
andy@8 43 """
andy@5 44 def __init__(self, name, q=None):
andy@1 45 self.name = name
andy@1 46 self.entries = {}
andy@5 47 self.q = _autotype(q)
andy@1 48
andy@1 49 def add_entry(self, entry):
andy@1 50 #print entry
andy@1 51 nextparent = self.entries
andy@1 52 if len(entry) < 2:
andy@1 53 raise Exception("Block entries must be at least a 2-tuple")
andy@4 54 #print "in", entry
andy@4 55 entry = map(_autotype, entry)
andy@4 56 #print "out", entry
andy@1 57 for e in entry[:-2]:
andy@1 58 if e is not entry[-1]:
andy@1 59 nextparent = nextparent.setdefault(e, {})
andy@1 60 nextparent[entry[-2]] = entry[-1]
andy@1 61 #print self.entries
andy@1 62
andy@1 63 def __cmp__(self, other):
andy@1 64 return self.name < other.name
andy@1 65
andy@1 66 def __str__(self):
andy@1 67 s = self.name
andy@5 68 if self.q is not None:
andy@5 69 s += " (Q=%s)" % self.q
andy@1 70 s += "\n"
andy@1 71 s += str(self.entries)
andy@1 72 return s
andy@1 73
andy@1 74
andy@12 75 class Decay(object):
andy@8 76 """
andy@8 77 Object representing a decay entry on a particle decribed by the SLHA file.
andy@8 78 'Decay' objects are not a direct representation of a DECAY block in an SLHA
andy@8 79 file... that role, somewhat confusingly, is taken by the Particle class.
andy@8 80
andy@8 81 Decay objects have three properties: a branching ratio, br, an nda number
andy@12 82 (number of daughters == len(ids)), and a tuple of PDG PIDs to which the
andy@12 83 decay occurs. The PDG ID of the particle whose decay this represents may
andy@12 84 also be stored, but this is normally known via the Particle in which the
andy@12 85 decay is stored.
andy@8 86 """
andy@8 87 def __init__(self, br, nda, ids, parentid=None):
andy@8 88 self.parentid = parentid
andy@6 89 self.br = br
andy@6 90 self.nda = nda
andy@6 91 self.ids = ids
andy@29 92 assert(self.nda == len(self.ids))
andy@6 93
andy@6 94 def __cmp__(self, other):
andy@6 95 return self.br < other.br
andy@6 96
andy@6 97 def __str__(self):
andy@12 98 return "%e %s" % (self.br, self.ids)
andy@6 99
andy@6 100
andy@12 101 class Particle(object):
andy@8 102 """
andy@8 103 Representation of a single, specific particle, decay block from an SLHA
andy@8 104 file. These objects are not themselves called 'Decay', since that concept
andy@8 105 applies more naturally to the various decays found inside this
andy@8 106 object. Particle classes store the PDG ID (pid) of the particle being
andy@8 107 represented, and optionally the mass (mass) and total decay width
andy@8 108 (totalwidth) of that particle in the SLHA scenario. Masses may also be found
andy@8 109 via the MASS block, from which the Particle.mass property is filled, if at
andy@8 110 all. They also store a list of Decay objects (decays) which are probably the
andy@8 111 item of most interest.
andy@8 112 """
andy@6 113 def __init__(self, pid, totalwidth=None, mass=None):
andy@6 114 self.pid = pid
andy@6 115 self.totalwidth = totalwidth
andy@6 116 self.mass = mass
andy@6 117 self.decays = []
andy@6 118
andy@6 119 def add_decay(self, br, nda, ids):
andy@6 120 self.decays.append(Decay(br, nda, ids))
andy@6 121 self.decays.sort()
andy@6 122
andy@6 123 def __cmp__(self, other):
andy@6 124 if abs(self.pid) == abs(other.pid):
andy@6 125 return self.pid < other.pid
andy@6 126 return abs(self.pid) < abs(other.pid)
andy@6 127
andy@6 128 def __str__(self):
andy@6 129 s = str(self.pid)
andy@7 130 if self.mass is not None:
andy@7 131 s += " : mass = %e GeV" % self.mass
andy@6 132 if self.totalwidth is not None:
andy@7 133 s += " : total width = %e GeV" % self.totalwidth
andy@6 134 for d in self.decays:
andy@12 135 if d.br > 0.0:
andy@12 136 s += "\n %s" % d
andy@6 137 return s
andy@1 138
andy@1 139
andy@21 140 def readSLHAFile(spcfilename):
andy@21 141 """
andy@21 142 Read an SLHA file, returning dictionaries of blocks and decays.
andy@21 143 """
andy@21 144 with open(spcfilename, "r") as f:
andy@21 145 return readSLHA(f.read())
andy@21 146
andy@21 147
andy@21 148 def readSLHA(spcstr):
andy@21 149 """
andy@21 150 Read an SLHA definition from a string, returning dictionaries of blocks and decays.
andy@21 151 """
andy@1 152 blocks = {}
andy@1 153 decays = {}
andy@21 154 #
andy@21 155 currentblock = None
andy@21 156 currentdecay = None
andy@21 157 for line in spcstr.splitlines():
andy@21 158 ## Handle (ignore) comment lines
andy@21 159 if line.startswith("#"):
andy@21 160 continue
andy@21 161 if "#" in line:
andy@21 162 line = line[:line.index("#")]
andy@21 163
andy@21 164 ## Handle BLOCK/DECAY start lines
andy@21 165 if line.upper().startswith("BLOCK"):
andy@21 166 match = re.match(r"BLOCK\s+(\w+)\s+(Q=\s*.+)?", line.upper())
andy@21 167 if not match:
andy@8 168 continue
andy@21 169 blockname = match.group(1)
andy@21 170 qstr = match.group(2)
andy@21 171 if qstr is not None:
andy@21 172 qstr = qstr[2:].strip()
andy@21 173 currentblock = blockname
andy@21 174 currentdecay = None
andy@21 175 blocks[blockname] = Block(blockname, q=qstr)
andy@21 176 elif line.upper().startswith("DECAY"):
andy@21 177 match = re.match(r"DECAY\s+(\d+)\s+([\d\.E+-]+).*", line.upper())
andy@21 178 if not match:
andy@21 179 continue
andy@21 180 pdgid = int(match.group(1))
andy@21 181 width = float(match.group(2))
andy@21 182 currentblock = "DECAY"
andy@21 183 currentdecay = pdgid
andy@21 184 decays[pdgid] = Particle(pdgid, width)
andy@21 185 else:
andy@21 186 ## In-block line
andy@21 187 if currentblock is not None:
andy@21 188 items = line.split()
andy@21 189 # TODO: Sort out tuple item types: autoconvert integers and floats
andy@21 190 if len(items) < 1:
andy@6 191 continue
andy@21 192 if currentblock != "DECAY":
andy@21 193 #print currentblock
andy@21 194 if len(items) < 2:
andy@21 195 ## Treat the ALPHA block differently
andy@21 196 blocks[currentblock].value = _autotype(items[0])
andy@21 197 blocks[currentblock].add_entry((0, items[0]))
andy@8 198 else:
andy@21 199 blocks[currentblock].add_entry(items)
andy@21 200 else:
andy@21 201 br = float(items[0])
andy@21 202 nda = int(items[1])
andy@21 203 ids = map(int, items[2:])
andy@21 204 decays[currentdecay].add_decay(br, nda, ids)
andy@1 205
andy@8 206 ## Try to populate Particle masses from the MASS block
andy@8 207 for pid in blocks["MASS"].entries.keys():
andy@8 208 if decays.has_key(pid):
andy@8 209 decays[pid].mass = blocks["MASS"].entries[pid]
andy@8 210
andy@1 211 return blocks, decays
andy@1 212
andy@1 213
andy@21 214
andy@29 215 def writeSLHAFile(spcfilename, blocks, decays):
andy@29 216 """
andy@29 217 Write an SLHA file from the supplied blocks and decays dicts.
andy@29 218 """
andy@29 219 with open(spcfilename, "w") as f:
andy@29 220 f.write(writeSLHA(blocks, decays))
andy@29 221
andy@29 222
andy@29 223 def writeSLHA(blocks, decays):
andy@29 224 """
andy@29 225 Return an SLHA definition as a string, from the supplied blocks and decays dicts.
andy@29 226 """
andy@29 227 out = ""
andy@30 228 def dict_hier_strs(d, s=""):
andy@30 229 if type(d) is dict:
andy@30 230 for k, v in sorted(d.iteritems()):
andy@30 231 for s2 in dict_hier_strs(v, "%s %s" % (s, _autostr(k))):
andy@30 232 yield s2
andy@30 233 else:
andy@30 234 yield "%s %s" % (s, _autostr(d))
andy@30 235 ## Blocks
andy@30 236 for bname, b in sorted(blocks.iteritems()):
andy@29 237 namestr = b.name
andy@29 238 if b.q is not None:
andy@29 239 namestr += " Q= %e" % b.q
andy@29 240 out += "BLOCK %s\n" % namestr
andy@30 241 for s in dict_hier_strs(b.entries):
andy@30 242 out += 5*" " + s + "\n"
andy@29 243 out += "\n"
andy@30 244 ## Decays
andy@30 245 for pid, particle in sorted(decays.iteritems()):
andy@29 246 out += "DECAY %d %e\n" % (particle.pid, particle.totalwidth)
andy@30 247 for d in sorted(particle.decays):
andy@29 248 products_str = " ".join(map(str, d.ids))
andy@29 249 out += 5*" " + "%e %d %s\n" % (d.br, len(d.ids), products_str)
andy@29 250 out += "\n"
andy@29 251 return out
andy@29 252
andy@29 253
andy@29 254
andy@1 255 if __name__ == "__main__":
andy@1 256 import sys
andy@1 257 for a in sys.argv[1:]:
andy@29 258 blocks, decays = readSLHAFile(a)
andy@3 259
andy@5 260 for bname, b in sorted(blocks.iteritems()):
andy@5 261 print b
andy@5 262 print
andy@3 263
andy@4 264 print blocks["MASS"].entries[25]
andy@6 265 print
andy@6 266
andy@6 267 for p in sorted(decays.values()):
andy@6 268 print p
andy@6 269 print
andy@29 270
andy@29 271 print writeSLHA(blocks, decays)

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