src/MEDLoader/Swig/CaseReader.py

   1 #  -*- coding: iso-8859-1 -*-
   2 # Copyright (C) 2007-2016  CEA/DEN, EDF R&D
   3 #
   4 # This library is free software; you can redistribute it and/or
   5 # modify it under the terms of the GNU Lesser General Public
   6 # License as published by the Free Software Foundation; either
   7 # version 2.1 of the License, or (at your option) any later version.
   8 #
   9 # This library is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 # Lesser General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU Lesser General Public
  15 # License along with this library; if not, write to the Free Software
  16 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  17 #
  18 # See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
  19 #
  20 # Author : Anthony GEAY (CEA/DEN/DM2S/STMF/LGLS)
  21
  22 # http://www-vis.lbl.gov/NERSC/Software/ensight/doc/OnlineHelp/UM-C11.pdf
  23 import numpy as np
  24 from MEDLoader import *
  25 from CaseIO import CaseIO
  26 import sys,re
  27
  28 class CaseReader(CaseIO):
  29     """ Converting a file in the Case format (Ensight) to the MED format.
  30     A new file with the same base name and the .med extension is created.
  31     """
  32
  33     @classmethod
  34     def New(cls,fileName):
  35         """ Static constructor. """
  36         return CaseReader(fileName)
  37         pass
  38
  39     def __init__(self,fileName):
  40         """ Constructor """
  41         self._fileName=fileName
  42         self._dirName=os.path.dirname(self._fileName)
  43         pass
  44
  45     def __traduceMesh(self,name,typ,coords,cells):
  46         """ Convert a CASE mesh into a MEDCouplingUMesh. """
  47         nbCoords=len(coords)
  48         coo=np.array(coords,dtype="float64") ; coo=coo.reshape(nbCoords,3)
  49         coo=DataArrayDouble(coo) ; coo=coo.fromNoInterlace()
  50         ct=self.dictMCTyp2[typ]
  51         m=MEDCouplingUMesh(name,MEDCouplingUMesh.GetDimensionOfGeometricType(ct))
  52         m.setCoords(coo)
  53         nbNodesPerCell=MEDCouplingMesh.GetNumberOfNodesOfGeometricType(ct)
  54         cI=DataArrayInt(len(cells)+1) ; cI.iota() ; cI*=nbNodesPerCell+1
  55         #
  56         cells2=cells.reshape(len(cells),nbNodesPerCell)
  57         if cells2.dtype=='int32':
  58             c2=DataArrayInt(cells2)
  59         else:
  60             c2=DataArrayInt(np.array(cells2,dtype="int32"))
  61             pass
  62         c=DataArrayInt(len(cells),nbNodesPerCell+1) ; c[:,0]=ct ; c[:,1:]=c2-1 ; c.rearrange(1)
  63         m.setConnectivity(c,cI,True)
  64         m.checkConsistency()
  65         return m
  66
  67     def __traduceMeshForPolyhed(self,name,coords,arr0,arr1,arr2):
  68         nbCoords=len(coords)
  69         coo=np.array(coords,dtype="float64") ; coo=coo.reshape(nbCoords,3)
  70         coo=DataArrayDouble(coo) ; coo=coo.fromNoInterlace()
  71         m=MEDCouplingUMesh(name,3)
  72         m.setCoords(coo)
  73         #
  74         arr2=arr2[:]-1
  75         arr0mc0=DataArrayInt(arr0) ; arr0mc0.computeOffsetsFull()
  76         arr0mc1=DataArrayInt(arr0).deepCopy()
  77         arr0mc2=DataArrayInt(len(arr0),2) ; arr0mc2[:,0]=DataArrayInt(arr0)-1 ; arr0mc2[:,1]=1 ; arr0mc2.rearrange(1) ; arr0mc2.computeOffsetsFull()
  78         arr0mc3=DataArrayInt.Range(0,2*len(arr0),2).buildExplicitArrByRanges(arr0mc2)
  79         arr1mc0=DataArrayInt(arr1) ; arr1mc0.computeOffsetsFull()
  80         arr1mc1=arr1mc0[arr0mc0] ; arr1mc1[1:]+=arr0mc0[1:]
  81         arr1mc2=DataArrayInt(arr1).deepCopy() ; arr1mc2+=1 ; arr1mc2.computeOffsetsFull()
  82         arr2mc0=(arr1mc2[1:])[arr0mc3]
  83         #
  84         c=DataArrayInt(arr1.size+arr2.size)
  85         c[arr1mc1[:-1]]=NORM_POLYHED
  86         c[arr2mc0]=-1
  87         a=arr2mc0.buildUnion(arr1mc1[:-1]).buildComplement(len(c))
  88         c[a]=DataArrayInt(arr2)
  89         #
  90         m.setConnectivity(c,arr1mc1,True)
  91         m.checkConsistency()
  92         return m
  93
  94     def __traduceMeshForPolygon(self,name,coords,arr0,arr1):
  95         nbCoords=len(coords)
  96         coo=np.array(coords,dtype="float64") ; coo=coo.reshape(nbCoords,3)
  97         coo=DataArrayDouble(coo) ; coo=coo.fromNoInterlace()
  98         m=MEDCouplingUMesh(name,2)
  99         m.setCoords(coo)
 100         #
 101         arr0_0=DataArrayInt(arr0+1) ; arr0_0.computeOffsetsFull()
 102         arr0_1=DataArrayInt(len(arr0),2) ; arr0_1[:,1]=DataArrayInt(arr0) ; arr0_1[:,0]=1 ; arr0_1.rearrange(1) ; arr0_1.computeOffsetsFull()
 103         arr0_2=DataArrayInt.Range(1,2*len(arr0),2).buildExplicitArrByRanges(arr0_1)
 104         c=DataArrayInt(len(arr0)+len(arr1)) ; c[:]=0 ; c[arr0_0[:-1]]=NORM_POLYGON
 105         c[arr0_2]=DataArrayInt(arr1-1)
 106         #
 107         m.setConnectivity(c,arr0_0,True)
 108         m.checkConsistency()
 109         return m
 110
 111     def __convertGeo2MED(self,geoFileName):
 112         """ Convert all the geometry (all the meshes) contained in teh CASE file into MEDCouplingUMesh'es. """
 113         fd=open(os.path.join(self._dirName,geoFileName),"r+b") ; fd.seek(0,2) ; end=fd.tell() ; fd.seek(0) ; title=fd.read(80)
 114         title=title.strip().lower()
 115         if "binary" not in title:
 116             raise Exception("Error only binary geo files are supported for the moment !")
 117             pass
 118         zeType=True
 119         if "fortran" in title:
 120             mcmeshes=self.__convertGeo2MEDFortran(fd,end) ; zeType=False
 121         else:
 122             mcmeshes=self.__convertGeo2MEDC(fd,end)
 123         #
 124         ms=MEDFileMeshes()
 125         ms.resize(len(mcmeshes))
 126         for i,m in enumerate(mcmeshes):
 127             mlm=MEDFileUMesh()
 128             mlm.setMeshAtLevel(0,m)
 129             ms.setMeshAtPos(i,mlm)
 130             pass
 131         return mcmeshes,ms,zeType
 132
 133     def __convertGeo2MEDFortran(self,fd,end):
 134         mcmeshes=[]
 135         fd.read(80) # comment 1
 136         fd.read(80) # comment 2
 137         fd.read(80) # node id
 138         fd.read(80) # element id
 139         pos=fd.tell()
 140         elt=fd.read(80) ; elt=elt.strip() ; pos=fd.tell()
 141         mcmeshes2=[]
 142         typ="part"
 143         nbOfTurn=0
 144         while abs(pos-end)>8 and "part" in typ:
 145             if "part" not in elt:
 146                 raise Exception("Error on reading mesh fortran #1 !")
 147             fd.seek(fd.tell()+4)# skip #
 148             tmp=fd.read(80) ; meshName=tmp.split("P")[-1]
 149             tmp=fd.read(80)
 150             if "coordinates" not in tmp:
 151                 raise Exception("Error on reading mesh fortran #2 !")
 152             pos=fd.tell() # 644
 153             if nbOfTurn==0:
 154                 pos+=76 # what else ?
 155             else:
 156                 pos+=40
 157                 pass
 158             nbNodes=np.memmap(fd,dtype='>i4',mode='r',offset=int(pos),shape=(1,)).tolist()[0]
 159             pos+=12 # what else ?
 160             a=np.memmap(fd,dtype='>f4',mode='r',offset=int(pos),shape=(nbNodes))
 161             b=np.memmap(fd,dtype='>f4',mode='r',offset=int(pos+nbNodes*4+2*4),shape=(nbNodes))
 162             c=np.memmap(fd,dtype='>f4',mode='r',offset=int(pos+nbNodes*2*4+4*4),shape=(nbNodes))
 163             coo=np.zeros(dtype=">f4",shape=(nbNodes*3))
 164             coo[:nbNodes]=a ; coo[nbNodes:2*nbNodes]=b ; coo[2*nbNodes:]=c
 165             coo=coo.reshape(nbNodes,3)
 166             pos+=nbNodes*3*4 ; fd.seek(pos)#np.array(0,dtype='float%i'%(typeOfCoo)).nbytes
 167             typ=fd.read(80).strip() ; pos=fd.tell()
 168             zeK=""
 169             for k in self.dictMCTyp2:
 170                 if k in typ:
 171                     zeK=k
 172                     break
 173                     pass
 174                 pass
 175             pos+=8*4 # yeh man !
 176             nbCellsOfType=np.memmap(fd,dtype='>i4',mode='r',offset=int(pos),shape=(1,)).tolist()[0]
 177             pos+=4 # for the number of cells
 178             pos+=2*4 # because it's great !
 179             nbNodesPerCell=MEDCouplingMesh.GetNumberOfNodesOfGeometricType(self.dictMCTyp2[zeK])
 180             nodalConn=np.memmap(fd,dtype='>i4',mode='r',offset=pos,shape=(nbCellsOfType,nbNodesPerCell))
 181             meshName=meshName.strip()
 182             mcmeshes2.append(self.__traduceMesh(meshName,zeK,coo,nodalConn))
 183             pos+=nbNodesPerCell*nbCellsOfType*4
 184             if abs(pos-end)>8:
 185                 fd.seek(pos) ;elt=fd.read(80) ; typ=elt[:] ; pos+=80
 186                 pass
 187             nbOfTurn+=1
 188             pass
 189         #coo=mcmeshes2[0].getCoords() ; name=mcmeshes2[0].getName()
 190         #for itmesh in mcmeshes2: itmesh.setCoords(coo)
 191         #m=MEDCouplingUMesh.MergeUMeshesOnSameCoords(mcmeshes2) ; m.setName(name)
 192         #mcmeshes.append(m)
 193         return mcmeshes2
 194
 195     def __convertGeo2MEDC(self,fd,end):
 196         fd.readline()
 197         name=fd.readline().strip() ; fd.readline() ; fd.readline()
 198         pos=fd.tell()
 199         mcmeshes=[]
 200         elt=fd.read(80) ; elt=elt.strip() ; pos+=80
 201         while pos!=end:
 202             if "part" not in elt:
 203                 raise Exception("Error on reading mesh #1 !")
 204             fd.seek(fd.tell()+4)
 205             meshName=fd.read(80).strip()
 206             if fd.read(len("coordinates"))!="coordinates":
 207                 raise Exception("Error on reading mesh #2 !")
 208             pos=fd.tell()
 209             typeOfCoo=np.memmap(fd,dtype='byte',mode='r',offset=int(pos),shape=(1)).tolist()[0]
 210             pos+=1+17*4
 211             nbNodes=np.memmap(fd,dtype='int32',mode='r',offset=int(pos),shape=(1,)).tolist()[0]
 212             pos+=4
 213             coo=np.memmap(fd,dtype='float32',mode='r',offset=int(pos),shape=(nbNodes,3))
 214             pos+=nbNodes*3*4 ; fd.seek(pos)#np.array(0,dtype='float%i'%(typeOfCoo)).nbytes
 215             typ=fd.read(80).strip() ; pos=fd.tell()
 216             mcmeshes2=[]
 217             while pos!=end and typ!="part":
 218                 if typ[0]=='\0': pos+=1; continue
 219                 mctyp=self.dictMCTyp2[typ]
 220                 nbCellsOfType=np.memmap(fd,dtype='int32',mode='r',offset=int(pos),shape=(1,)).tolist()[0]
 221                 pos+=4
 222                 if mctyp!=NORM_POLYHED and mctyp!=NORM_POLYGON:
 223                     nbNodesPerCell=MEDCouplingMesh.GetNumberOfNodesOfGeometricType(mctyp)
 224                     cells=np.memmap(fd,dtype='int32',mode='r',offset=pos,shape=(nbCellsOfType,nbNodesPerCell))
 225                     pos+=nbCellsOfType*nbNodesPerCell*4
 226                     fd.seek(pos)
 227                     mcmeshes2.append(self.__traduceMesh(meshName,typ,coo,cells))
 228                 elif mctyp==NORM_POLYHED:
 229                     nbOfFacesPerCell=np.memmap(fd,dtype='int32',mode='r',offset=int(pos),shape=(nbCellsOfType,))
 230                     pos+=nbCellsOfType*4
 231                     szOfNbOfNodesPerFacePerCellArr=int(nbOfFacesPerCell.sum())
 232                     arr1=np.memmap(fd,dtype='int32',mode='r',offset=int(pos),shape=(szOfNbOfNodesPerFacePerCellArr,))#arr1 -> nbOfNodesPerFacePerCellArr
 233                     pos+=szOfNbOfNodesPerFacePerCellArr*4
 234                     szOfNodesPerFacePerCellArr=arr1.sum()
 235                     arr2=np.memmap(fd,dtype='int32',mode='r',offset=int(pos),shape=(szOfNodesPerFacePerCellArr,))#arr2 -> nodesPerFacePerCellArr
 236                     pos+=szOfNodesPerFacePerCellArr*4 ; fd.seek(pos)
 237                     mcmeshes2.append(self.__traduceMeshForPolyhed(meshName,coo,nbOfFacesPerCell,arr1,arr2))
 238                     pass
 239                 else:
 240                     nbOfNodesPerCell=np.memmap(fd,dtype='int32',mode='r',offset=int(pos),shape=(nbCellsOfType,))
 241                     pos+=nbCellsOfType*4
 242                     szOfNbOfNodesPerCellArr=int(nbOfNodesPerCell.sum())
 243                     arr1=np.memmap(fd,dtype='int32',mode='r',offset=int(pos),shape=(szOfNbOfNodesPerCellArr,))
 244                     pos+=szOfNbOfNodesPerCellArr*4  ; fd.seek(pos)
 245                     mcmeshes2.append(self.__traduceMeshForPolygon(meshName,coo,nbOfNodesPerCell,arr1))
 246                 if pos!=end:
 247                     elt=fd.read(80) ; elt=elt.strip() ; typ=elt[:] ; pos+=80
 248                     pass
 249                 pass
 250             if mcmeshes2:
 251                 coo=mcmeshes2[0].getCoords() ; name=mcmeshes2[0].getName()
 252                 for itmesh in mcmeshes2: itmesh.setCoords(coo)
 253                 m=MEDCouplingUMesh.MergeUMeshesOnSameCoords(mcmeshes2) ; m.setName(name)
 254                 mcmeshes.append(m)
 255             pass
 256         return mcmeshes
 257
 258
 259     def __convertField(self,mlfields, mcmeshes, fileName, fieldName, discr, nbCompo, locId, it):
 260         """ Convert the fields. """
 261         stars=re.search("[\*]+",fileName).group()
 262         st="%0"+str(len(stars))+"i"
 263         trueFileName=fileName.replace(stars,st%(it))
 264         fd=open(os.path.join(self._dirName,trueFileName),"r+b") ; fd.seek(0,2) ; end=fd.tell() ; fd.seek(0)
 265         name=fd.readline().strip().split(" ")[0]
 266         if name!=fieldName:
 267             raise Exception("ConvertField : mismatch")
 268         pos=fd.tell()
 269         st=fd.read(80) ; st=st.strip() ; pos=fd.tell()
 270         while pos!=end:
 271             if st!="part":
 272                 raise Exception("ConvertField : mismatch #2")
 273             fdisc=MEDCouplingFieldDiscretization.New(self.discSpatial2[discr])
 274             meshId=np.memmap(fd,dtype='int32',mode='r',offset=int(pos),shape=(1)).tolist()[0]-1
 275             if meshId >= len( mcmeshes ):
 276                 return
 277             nbOfValues=fdisc.getNumberOfTuples(mcmeshes[meshId])
 278             vals2=DataArrayDouble(nbOfValues,nbCompo)
 279             fd.seek(pos+4)
 280             st=fd.read(80).strip() ; pos=fd.tell()
 281             offset=0
 282             while pos!=end and st!="part":
 283                 if st!="coordinates":
 284                     nbOfValsOfTyp=mcmeshes[meshId].getNumberOfCellsWithType(self.dictMCTyp2[st])
 285                 else:
 286                     nbOfValsOfTyp=nbOfValues
 287                     pass
 288                 vals=np.memmap(fd,dtype='float32',mode='r',offset=int(pos),shape=(nbOfValsOfTyp,nbCompo))#np.memmap(fd,dtype='int32',mode='r',offset=159,shape=(1))
 289                 vals2[offset:offset+nbOfValsOfTyp]=DataArrayDouble(np.array(vals,dtype='float64')).fromNoInterlace()
 290                 pos+=nbOfValsOfTyp*nbCompo*4 ; fd.seek(pos)
 291                 st=fd.read(80) ; st=st.strip() ; pos=fd.tell()
 292                 offset+=nbOfValsOfTyp
 293                 pass
 294             f=MEDCouplingFieldDouble(self.discSpatial2[discr],ONE_TIME) ; f.setName("%s_%s"%(fieldName,mcmeshes[meshId].getName()))
 295             f.setMesh(mcmeshes[meshId]) ; f.setArray(vals2) ; f.setTime(float(it),it,-1)
 296             f.checkConsistencyLight()
 297             mlfields[locId+meshId].appendFieldNoProfileSBT(f)
 298             pass
 299
 300     def __convertFieldFortran(self,mlfields, mcmeshes, fileName, fieldName, discr, nbCompo, locId, it):
 301         """ Convert the fields. """
 302         if re.search("[\*]+",fileName):
 303             stars=re.search("[\*]+",fileName).group()
 304             st="%0"+str(len(stars))+"i"
 305             trueFileName=fileName.replace(stars,st%(it))
 306             pass
 307         else:
 308             trueFileName=fileName
 309             pass
 310         fd=open(os.path.join(self._dirName,trueFileName),"r+b") ; fd.seek(0,2) ; end=fd.tell() ; fd.seek(0)
 311         name=fd.read(80)
 312         if fieldName not in name:
 313             raise Exception("ConvertField : mismatch")
 314         pos=fd.tell()
 315         st=fd.read(80) ; st=st.strip() ; pos=fd.tell()
 316         if "part" not in st:
 317             raise Exception("ConvertField : mismatch #2")
 318         st=fd.read(80).strip() ; pos=fd.tell()
 319         pos+=12 # I love it
 320         offset=0
 321         nbTurn=0
 322         while pos!=end and "part" not in st:
 323             fdisc=MEDCouplingFieldDiscretization.New(self.discSpatial2[discr])
 324             nbOfValues=fdisc.getNumberOfTuples(mcmeshes[nbTurn])
 325             vals2=DataArrayDouble(nbOfValues,nbCompo)
 326             pos+=24 # I love it again !
 327             nbOfValsOfTyp=np.memmap(fd,dtype='>i4',mode='r',offset=pos,shape=(1)).tolist()[0]/4
 328             pos+=4
 329             vals=np.zeros(dtype=">f4",shape=(nbOfValsOfTyp*nbCompo))
 330             for iii in range(nbCompo):
 331                 valsTmp=np.memmap(fd,dtype='>f4',mode='r',offset=int(pos),shape=(nbOfValsOfTyp))
 332                 vals[iii*nbOfValsOfTyp:(iii+1)*nbOfValsOfTyp]=valsTmp
 333                 pos+=nbOfValsOfTyp*4
 334                 pos+=2*4 ## hey hey, that is the ultimate class !
 335                 vals2.setInfoOnComponent(iii,chr(ord('X')+iii))
 336                 pass
 337             if pos>end:
 338                 pos=end
 339                 pass
 340             vals=vals.reshape(nbOfValsOfTyp,nbCompo)
 341             vals2[offset:offset+nbOfValsOfTyp]=DataArrayDouble(np.array(vals,dtype='float64')).fromNoInterlace()
 342             if pos!=end:
 343                 fd.seek(pos)
 344                 st=fd.read(80) ; st=st.strip() ; pos=fd.tell()
 345                 st=fd.read(80) ; st=st.strip() ; pos=fd.tell()
 346                 pass
 347             f=MEDCouplingFieldDouble(self.discSpatial2[discr],ONE_TIME) ; f.setName("%s_%s"%(fieldName,mcmeshes[nbTurn].getName()))
 348             f.setMesh(mcmeshes[nbTurn]) ; f.setArray(vals2) ; f.setTime(float(it),it,-1)
 349             f.checkConsistencyLight()
 350             mlfields[locId+nbTurn].appendFieldNoProfileSBT(f)
 351             nbTurn+=1
 352             pass
 353         pass
 354
 355     def loadInMEDFileDS(self):
 356         """ Load a CASE file into a MEDFileData object. """
 357         f=file(self._fileName)
 358         lines=f.readlines()
 359         ind=lines.index("GEOMETRY\n")
 360         if ind==-1:
 361             raise Exception("Error with file %s"%(fname))
 362         geoName=re.match("model:([\W]*)([\w\.]+)",lines[ind+1]).group(2)
 363         m1,m2,typeOfFile=self.__convertGeo2MED(geoName)
 364         fieldsInfo=[] ; nbOfTimeSteps=0
 365         if "VARIABLE\n" in lines:
 366             ind=lines.index("VARIABLE\n")
 367             end=len(lines)-1
 368             if "TIME\n" in lines:
 369                 end=lines.index("TIME\n")
 370                 pass
 371             for i in range(ind + 1, end):
 372                 m=re.match("^([\w]+)[\s]+\per[\s]+([\w]+)[\s]*\:[\s]*([\w]+)[\s]+([\S]+)$",lines[i])
 373                 if m:
 374                     if m.groups()[0]=="constant":
 375                         continue
 376                     spatialDisc=m.groups()[1] ; fieldName=m.groups()[2] ; nbOfCompo=self.dictCompo2[m.groups()[0]] ; fieldFileName=m.groups()[3]
 377                     fieldsInfo.append((fieldName,spatialDisc,nbOfCompo,fieldFileName))
 378                     pass
 379                 pass
 380
 381             expr=re.compile("number[\s]+of[\s]+steps[\s]*\:[\s]*([\d]+)")
 382             tmp = [line for line in lines if expr.search(line)]
 383             if tmp:
 384                 nbOfTimeSteps = int(expr.search(tmp[0]).group(1))
 385                 expr=re.compile("filename[\s]+start[\s]+number[\s]*\:[\s]*([\d]+)")
 386                 startIt = int(expr.search([line for line in lines if expr.search(line)][0]).group(1))
 387                 expr=re.compile("filename[\s]+increment[\s]*\:[\s]*([\d]+)")
 388                 incrIt = int(expr.search([line for line in lines if expr.search(line)][0]).group(1))
 389             else:
 390                 nbOfTimeSteps=1
 391                 startIt=0
 392                 incrIt=1
 393                 pass
 394             curIt=startIt
 395             pass
 396         mlfields=MEDFileFields()
 397         mlfields.resize(len(fieldsInfo)*len(m1))
 398         i=0
 399         for field in fieldsInfo:
 400             for m in m1:
 401                 mlfields.setFieldAtPos(i,MEDFileFieldMultiTS())
 402                 i+=1
 403                 pass
 404             pass
 405         for ts in range(nbOfTimeSteps):
 406             i=0
 407             for field in fieldsInfo:
 408                 if typeOfFile:
 409                     self.__convertField(mlfields,m1,field[3],field[0],field[1],field[2],i,curIt);
 410                 else:
 411                     self.__convertFieldFortran(mlfields,m1,field[3],field[0],field[1],field[2],i,curIt)
 412                     pass
 413                 i+=len(m1)
 414                 pass
 415             curIt+=incrIt
 416             pass
 417         ret=MEDFileData()
 418         ret.setMeshes(m2)
 419         del mlfields[[x for x in range(len(mlfields)) if len(mlfields[x]) == 0]]
 420         ret.setFields(mlfields)
 421         return ret
 422
 423     pass