mirror of
https://github.com/NGSolve/netgen.git
synced 2024-09-22 09:42:50 +05:00
219 lines
8.4 KiB
Python
219 lines
8.4 KiB
Python
from netgen.meshing import *
|
|
|
|
def ReadGmsh(filename):
|
|
if not filename.endswith(".msh"):
|
|
filename += ".msh"
|
|
meshdim = 1
|
|
with open(filename, 'r') as f:
|
|
while f.readline().split()[0] != "$Elements":
|
|
pass
|
|
nelem = int(f.readline())
|
|
for i in range(nelem):
|
|
line = f.readline()
|
|
eltype = int(line.split()[1])
|
|
if eltype > 1 and eltype != 15:
|
|
meshdim = 2
|
|
if eltype > 3 and eltype != 15:
|
|
meshdim = 3
|
|
break
|
|
|
|
f = open(filename, 'r')
|
|
mesh = Mesh(dim=meshdim)
|
|
|
|
pointmap = {}
|
|
facedescriptormap = {}
|
|
namemap = { 0 : { 0 : "default" },
|
|
1: { 0 : "default" },
|
|
2: { 0 : "default" },
|
|
3: { 0 : "default" } }
|
|
materialmap = {}
|
|
bbcmap = {}
|
|
|
|
segm = 1
|
|
trig = 2
|
|
quad = 3
|
|
tet = 4
|
|
hex = 5
|
|
prism = 6
|
|
pyramid = 7
|
|
segm3 = 8 # 2nd order line
|
|
trig6 = 9 # 2nd order trig
|
|
tet10 = 11 # 2nd order tet
|
|
point = 15
|
|
quad8 = 16 # 2nd order quad
|
|
hex20 = 17 # 2nd order hex
|
|
prism15 = 18 # 2nd order prism
|
|
pyramid13 = 19 # 2nd order pyramid
|
|
segms = [segm, segm3]
|
|
trigs = [trig, trig6]
|
|
quads = [quad, quad8]
|
|
tets = [tet, tet10]
|
|
hexes = [hex, hex20]
|
|
prisms = [prism, prism15]
|
|
pyramids = [pyramid, pyramid13]
|
|
elem0d = [point]
|
|
elem1d = segms
|
|
elem2d = trigs + quads
|
|
elem3d = tets + hexes + prisms + pyramids
|
|
|
|
num_nodes_map = { segm : 2,
|
|
trig : 3,
|
|
quad : 4,
|
|
tet : 4,
|
|
hex : 8,
|
|
prism : 6,
|
|
pyramid : 5,
|
|
segm3 : 3,
|
|
trig6 : 6,
|
|
tet10 : 10,
|
|
point : 1,
|
|
quad8 : 8,
|
|
hex20 : 20,
|
|
prism15 : 18,
|
|
pyramid13 : 19 }
|
|
|
|
while True:
|
|
line = f.readline()
|
|
if line == "":
|
|
break
|
|
|
|
if line.split()[0] == "$PhysicalNames":
|
|
print('WARNING: Physical groups detected - Be sure to define them for every geometrical entity.')
|
|
numnames = int(f.readline())
|
|
for i in range(numnames):
|
|
f.readline
|
|
line = f.readline()
|
|
namemap[int(line.split()[0])][int(line.split()[1])] = line.split()[2][1:-1]
|
|
|
|
if line.split()[0] == "$Nodes":
|
|
num = int(f.readline().split()[0])
|
|
for i in range(num):
|
|
line = f.readline()
|
|
nodenum, x, y, z = line.split()[0:4]
|
|
pnum = mesh.Add(MeshPoint(Pnt(float(x), float(y), float(z))))
|
|
pointmap[int(nodenum)] = pnum
|
|
|
|
if line.split()[0] == "$Elements":
|
|
num = int(f.readline().split()[0])
|
|
|
|
for i in range(num):
|
|
line = f.readline().split()
|
|
elmnum = int(line[0])
|
|
elmtype = int(line[1])
|
|
numtags = int(line[2])
|
|
# the first tag is the physical group nr, the second tag is the group nr of the dim
|
|
tags = [int(line[3 + k]) for k in range(numtags)]
|
|
|
|
if elmtype not in num_nodes_map:
|
|
raise Exception("element type", elmtype, "not implemented")
|
|
num_nodes = num_nodes_map[elmtype]
|
|
|
|
nodenums = line[3 + numtags:3 + numtags + num_nodes]
|
|
nodenums2 = [pointmap[int(nn)] for nn in nodenums]
|
|
|
|
if elmtype in elem1d:
|
|
if meshdim == 3:
|
|
if tags[1] in bbcmap:
|
|
index = bbcmap[tags[1]]
|
|
else:
|
|
index = len(bbcmap) + 1
|
|
if len(namemap):
|
|
mesh.SetCD2Name(index, namemap[1][tags[0]])
|
|
else:
|
|
mesh.SetCD2Name(index, "line" + str(tags[1]))
|
|
bbcmap[tags[1]] = index
|
|
|
|
elif meshdim == 2:
|
|
if tags[1] in facedescriptormap.keys():
|
|
index = facedescriptormap[tags[1]]
|
|
else:
|
|
index = len(facedescriptormap) + 1
|
|
fd = FaceDescriptor(bc=index)
|
|
if len(namemap):
|
|
fd.bcname = namemap[1][tags[0]]
|
|
else:
|
|
fd.bcname = 'line' + str(tags[1])
|
|
mesh.SetBCName(index - 1, fd.bcname)
|
|
mesh.Add(fd)
|
|
facedescriptormap[tags[1]] = index
|
|
else:
|
|
if tags[1] in materialmap:
|
|
index = materialmap[tags[1]]
|
|
else:
|
|
index = len(materialmap) + 1
|
|
if len(namemap):
|
|
mesh.SetMaterial(index, namemap[1][tags[0]])
|
|
else:
|
|
mesh.SetMaterial(index, "line" + str(tags[1]))
|
|
materialmap[tags[1]] = index
|
|
|
|
mesh.Add(Element1D(index=index, vertices=nodenums2))
|
|
|
|
if elmtype in elem2d: # 2d elements
|
|
if meshdim == 3:
|
|
if tags[1] in facedescriptormap.keys():
|
|
index = facedescriptormap[tags[1]]
|
|
else:
|
|
index = len(facedescriptormap) + 1
|
|
fd = FaceDescriptor(bc=index)
|
|
if len(namemap):
|
|
fd.bcname = namemap[2][tags[0]]
|
|
else:
|
|
fd.bcname = "surf" + str(tags[1])
|
|
mesh.SetBCName(index - 1, fd.bcname)
|
|
mesh.Add(fd)
|
|
facedescriptormap[tags[1]] = index
|
|
else:
|
|
if tags[1] in materialmap:
|
|
index = materialmap[tags[1]]
|
|
else:
|
|
index = len(materialmap) + 1
|
|
if len(namemap):
|
|
mesh.SetMaterial(index, namemap[2][tags[0]])
|
|
else:
|
|
mesh.SetMaterial(index, "surf" + str(tags[1]))
|
|
materialmap[tags[1]] = index
|
|
|
|
if elmtype in trigs:
|
|
ordering = [i for i in range(3)]
|
|
if elmtype == trig6:
|
|
ordering += [4,5,3]
|
|
if elmtype in quads:
|
|
ordering = [i for i in range(4)]
|
|
if elmtype == quad8:
|
|
ordering += [4, 6, 7, 5]
|
|
mesh.Add(Element2D(index, [nodenums2[i] for i in ordering]))
|
|
|
|
if elmtype in elem3d: # volume elements
|
|
if tags[1] in materialmap:
|
|
index = materialmap[tags[1]]
|
|
else:
|
|
index = len(materialmap) + 1
|
|
if len(namemap):
|
|
mesh.SetMaterial(index, namemap[3][tags[0]])
|
|
else:
|
|
mesh.SetMaterial(index, "vol" + str(tags[1]))
|
|
materialmap[tags[1]] = index
|
|
|
|
nodenums2 = [pointmap[int(nn)] for nn in nodenums]
|
|
|
|
if elmtype in tets:
|
|
ordering = [0,1,2,3]
|
|
if elmtype == tet10:
|
|
ordering += [4,6,7,5,9,8]
|
|
elif elmtype in hexes:
|
|
ordering = [0,1,5,4,3,2,6,7]
|
|
if elmtype == hex20:
|
|
ordering += [8,16,10,12,13,19,15,14,9,11,18,17]
|
|
elif elmtype in prisms:
|
|
ordering = [0,2,1,3,5,4]
|
|
if elmtype == prism15:
|
|
ordering += [7,6,9,8,11,10,13,12,14]
|
|
elif elmtype in pyramids:
|
|
ordering = [3,2,1,0,4]
|
|
if elmtype == pyramid13:
|
|
ordering += [10,5,6,8,12,11,9,7]
|
|
mesh.Add(Element3D(index, [nodenums2[i] for i in ordering]))
|
|
|
|
return mesh
|