/[escript]/trunk/pycad/py_src/Triangle.py
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Contents of /trunk/pycad/py_src/Triangle.py

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Revision 6939 - (show annotations)
Mon Jan 20 03:37:18 2020 UTC (17 months ago) by uqaeller
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Updated the copyright header.


1
2 ##############################################################################
3 #
4 # Copyright (c) 2003-2020 by The University of Queensland
5 # http://www.uq.edu.au
6 #
7 # Primary Business: Queensland, Australia
8 # Licensed under the Apache License, version 2.0
9 # http://www.apache.org/licenses/LICENSE-2.0
10 #
11 # Development until 2012 by Earth Systems Science Computational Center (ESSCC)
12 # Development 2012-2013 by School of Earth Sciences
13 # Development from 2014 by Centre for Geoscience Computing (GeoComp)
14 # Development from 2019 by School of Earth and Environmental Sciences
15 #
16 ##############################################################################
17
18 from __future__ import print_function, division
19
20 __copyright__="""Copyright (c) 2003-2020 by The University of Queensland
21 http://www.uq.edu.au
22 Primary Business: Queensland, Australia"""
23 __license__="""Licensed under the Apache License, version 2.0
24 http://www.apache.org/licenses/LICENSE-2.0"""
25 __url__="https://launchpad.net/escript-finley"
26
27 """
28 mesh generation using Triangle
29
30 :var __author__: name of author
31 :var __copyright__: copyrights
32 :var __license__: licence agreement
33 :var __url__: url entry point on documentation
34 :var __version__: version
35 :var __date__: date of the version
36 """
37
38 __author__="Brett Tully, b.tully@uq.edu.au"
39
40 import tempfile
41 import os
42 import glob
43 import esys.pycad.design as design
44 import math
45 from esys.pycad.primitives import Point, Spline, BezierCurve, BSpline, Line, Arc, CurveLoop, RuledSurface, PlaneSurface, SurfaceLoop, Volume, PropertySet
46 from esys.escript import getMPIWorldMax, getMPIRankWorld
47
48 class Design(design.AbstractDesign):
49 """
50 Design for Triangle.
51 """
52 def __init__(self,dim=2,keep_files=False):
53 """
54 Initializes the Triangle design.
55
56 :param dim: spatial dimension
57 :param keep_files: flag to keep work files
58 """
59 if dim != 2:
60 raise ValueError("only dimension 2 is supported by Triangle.")
61 design.AbstractDesign.__init__(self,dim=dim,keep_files=keep_files)
62 self.__scriptname=""
63 self.setScriptFileName()
64 self.setMeshFileName()
65 self.setOptions()
66
67 def setScriptFileName(self,name=None):
68 """
69 Sets the filename for the Triangle input script. If no name is given
70 a name with extension `poly` is generated.
71 """
72 if self.__scriptname:
73 os.unlink(self.__scriptname)
74 if name == None:
75 self.__scriptname_set=False
76 self.__scriptname=tempfile.mkstemp(suffix=".poly")[1]
77 else:
78 self.__scriptname_set=True
79 self.__scriptname=name
80 self.setMeshFileName(name)
81
82 def getScriptFileName(self):
83 """
84 Returns the name of the gmsh script file.
85 """
86 return self.__scriptname
87
88 def setMeshFileName(self,name=None):
89 """
90 Sets the name of the Triangle mesh file.
91 """
92 if self.__mshname:
93 os.unlink(self.__mshname)
94 if name == None:
95 self.__mshname=tempfile.mkstemp(suffix="")[1]
96 else:
97 # Triangle creates a default filename so all we want to pass is
98 # the basename
99 if (".poly" in name) or (".ele" in name) or (".node" in name):
100 s=name.split(".")[:-1]
101 name=s[0]
102 if len(s) > 1: name+=".%s"*(len(s)-1)%tuple(s[1:])
103 self.__mshname=name
104 self.setKeepFilesOn()
105
106 def getMeshFileName(self):
107 """
108 Returns the name of the Triangle mesh file.
109 """
110 return self.__mshname
111
112 def setOptions(self,cmdLineArgs=""):
113 """
114 Sets command line options for the mesh generator::
115
116 triangle [-prq__a__uAcDjevngBPNEIOXzo_YS__iFlsCQVh] input_file
117
118 see http://www.cs.cmu.edu/~quake/triangle.switch.html
119
120 :param cmdLineArgs: the switches you would ordinarily use at the
121 command line (e.g. cmdLineArgs="pq25a7.5")
122 """
123 self.__cmdLineArgs=cmdLineArgs
124
125 def __del__(self):
126 """
127 Cleans up.
128 """
129 if not self.keepFiles():
130 if not self.__scriptname_set:
131 os.unlink(self.getScriptFileName())
132 if not self.__mshname_set:
133 os.unlink(self.getMeshFileName())
134
135 def getCommandString(self):
136 """
137 Returns the Triangle command line::
138
139 triangle [-prq__a__uAcDjevngBPNEIOXzo_YS__iFlsCQVh] input_file
140
141 see http://www.cs.cmu.edu/~quake/triangle.switch.html
142 """
143 if self.__cmdLineArgs == "":
144 print("warning: using default command line arguments for Triangle")
145 exe="triangle %s %%s"%self.__cmdLineArgs
146 return exe
147
148 def getMeshHandler(self):
149 """
150 Returns a handle to a mesh meshing the design. In the current
151 implementation a mesh file name in Triangle format is returned.
152 """
153 args = self.getCommandString().split()
154 args[-1]=args[-1]%self.getScriptFileName()
155 if getMPIRankWorld() == 0:
156 import subprocess
157 open(self.getScriptFileName(),"w").write(self.getScriptString())
158 ret = subprocess.call(args) / 256
159 else:
160 ret=0
161 ret=getMPIWorldMax(ret)
162 if ret > 0:
163 raise RuntimeError("Could not build mesh: %s"%" ".join(args))
164 else:
165 # <hack> so that users can set the mesh filename they want.
166 name=self.getScriptFileName()
167 if (".poly" in name) or (".ele" in name) or (".node" in name):
168 s=name.split(".")[:-1]
169 name=s[0]
170 if len(s) > 1: name+=".%s"*(len(s)-1)%tuple(s[1:])
171 files=glob.glob("%s.1.*"%name)
172 for f in files:
173 sufx=f.split(".")[-1]
174 mshName=self.getMeshFileName()+"."+sufx
175 os.rename(f,mshName)
176 # </hack>
177 return self.getMeshFileName()
178
179 def getScriptString(self):
180 """
181 Returns the Triangle script to generate the mesh.
182 """
183 # comment lines are prefixed by a '#' in triangle *.poly files
184 out="# generated by esys.pycad\n"
185 vertices="";vertCnt=0
186 segments="";segCnt=0
187 holestr="";holeCnt=0
188 ctrlPts={}
189 for prim in self.getItems():
190
191 p=prim.getUnderlyingPrimitive()
192
193 if isinstance(p, PropertySet):
194 PSprims=p.getItems()
195 for PSp in PSprims:
196 if isinstance(PSp, Point):
197 c=PSp.getCoordinates()
198 vertCnt+=1
199 vertices+="%s %s %s %s\n"%(vertCnt,c[0],c[1],p.getID())
200
201 elif isinstance(PSp, Line):
202 # get end points and add them as vertices
203 # add line segments - bnd_mkr's are p.getID()
204 # and p.getID() should be mapped to the FID's from the GIS
205 pts=list(PSp.getControlPoints())
206 for pt in pts:
207 c=pt.getCoordinates()
208 if pt not in list(ctrlPts.keys()):
209 vertCnt+=1
210 vertices+="%s %s %s %s\n"%(vertCnt,c[0],c[1],p.getID())
211 ctrlPts[pt]=vertCnt
212 ptIndx=pts.index(pt)
213 if ptIndx != 0:
214 segCnt+=1
215 segments+="%s %s %s %s\n"%(segCnt,
216 ctrlPts[pts[ptIndx-1]],
217 ctrlPts[pts[ptIndx]],
218 p.getID())
219
220 elif isinstance(PSp, Spline) or isinstance(PSp, BezierCurve) or \
221 isinstance(PSp, BSpline) or isinstance(PSp, Arc):
222 TypeError("Triangle can only handle linear curves: not %s objects."%str(type(p)))
223
224 elif isinstance(PSp, PlaneSurface):
225
226 outerBnd=PSp.getBoundaryLoop()
227 holes=PSp.getHoles()
228
229 for curve in outerBnd.getCurves():
230 pts=list(curve.getControlPoints())
231 for pt in pts:
232 c=pt.getCoordinates()
233 if pt not in list(ctrlPts.keys()):
234 vertCnt+=1
235 vertices+="%s %s %s %s\n"%(vertCnt,c[0],c[1],p.getID())
236 ctrlPts[pt]=vertCnt
237 ptIndx=pts.index(pt)
238 if ptIndx != 0:
239 segCnt+=1
240 segments+="%s %s %s %s\n"%(segCnt,
241 ctrlPts[pts[ptIndx-1]],
242 ctrlPts[pts[ptIndx]],
243 p.getID())
244 # in order to deal with holes in Triangle, you must place a hole node inside
245 # the boundary of the polygon that describes the hole. For a convex polygon
246 # (all internal angles < 180 degrees) this is easy, however, for concave
247 # polygons (one or more internal angles > 180 degrees) this is much
248 # more difficult. Easiest method is to find the smallest internal angle, and
249 # place the hole node inside the triangle formed by the three vertices
250 # associated with that internal angle.
251 for hole in holes:
252 holePts=[]
253 for curve in hole.getCurves():
254 pts=list(curve.getControlPoints())
255 for pt in pts:
256 c=pt.getCoordinates()
257 if pt not in list(ctrlPts.keys()):
258 vertCnt+=1
259 vertices+="%s %s %s %s\n"%(vertCnt,c[0],c[1],p.getID())
260 ctrlPts[pt]=vertCnt
261 ptIndx=pts.index(pt)
262 if ptIndx != 0:
263 segCnt+=1
264 segments+="%s %s %s %s\n"%(segCnt,
265 ctrlPts[pts[ptIndx-1]],
266 ctrlPts[pts[ptIndx]],
267 p.getID())
268 if pt not in holePts:
269 holePts.append(pt)
270 vectors=[] # the key corresponds to the ctrlPts index
271 # create vectors
272 for i in range(len(holePts)):
273 A=holePts[i]
274 vectors.append([])
275 if i == 0:
276 B=holePts[1]
277 C=holePts[-1]
278 elif i == len(holePts)-1:
279 B=holePts[0]
280 C=holePts[-2]
281 else:
282 B=holePts[i+1]
283 C=holePts[i-1]
284 vectors[i].append(self.__getVector(A,B))
285 vectors[i].append(self.__getVector(A,C))
286 # get angle between vectors at each vertex
287 for i in range(len(vectors)):
288 angle=self.__getAngle(vectors[i][0],vectors[i][1])
289 vectors[i].append(angle)
290 # find the vertex with the smallest angle
291 minAngle=360.
292 indx=0
293 for i in range(len(vectors)):
294 if vectors[i][2] < minAngle:
295 indx=i
296 minAngle=vectors[i][2]
297 # find a node inside the triangle stemming from the
298 # vertex with the smallest internal angle. Do this by
299 # adding 5% of each of the vectorsesys.pycad. to the current point
300 A=holePts[indx]
301 cA=A.getCoordinates()
302 x=cA[0]+(vectors[indx][0][0]+vectors[indx][1][0])/20.
303 y=cA[1]+(vectors[indx][0][1]+vectors[indx][1][1])/20.
304 # use this node to define the hole.
305 holeCnt+=1
306 holestr+="%s %s %s\n"%(holeCnt,x,y)
307
308 else:
309 raise TypeError("please pass correct PropertySet objects to Triangle design")
310 else:
311 raise TypeError("please pass only PropertySet objects to Triangle design")
312 out+="# vertices #\n"
313 out+="%i 2 0 1\n"%(vertCnt)
314 out+=vertices
315 out+="# segments #\n"
316 out+="%i 1\n"%(segCnt)
317 out+=segments
318 out+="# holes #\n"
319 out+="%i\n"%(holeCnt)
320 out+=holestr
321 return out
322
323 def __getVector(self,A,B):
324 # get the vector between two points.
325 cA=A.getCoordinates()
326 cB=B.getCoordinates()
327 x=cB[0]-cA[0]
328 y=cB[1]-cA[1]
329 return [x,y]
330
331 def __getAngle(self,v,w):
332 # get internal (directional) angle between two vectors (in degrees).
333 theta=atan2(v[1],v[0]) - atan2(w[1],w[0])
334 theta=theta*180./pi
335 if theta < 0.:
336 theta+=360.
337 return theta
338

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