def surface_weight(refine, gtype):
if (refine, gtype) in globals()['weight']:
return globals()['weight'][(refine, gtype)]
quad_v = [[0, 0], [1, 0], [1, 1], [0, 3]]
quad_e = [[0, 1, 2, 3]]
tri_v = [[0, 0], [1, 0], [0, 1]]
tri_e = [[0, 1, 2,]]
seg_v = [[0,], [1, ],]
seg_e = [[0, 1,]]
if gtype == mfem.Geometry.TRIANGLE:
mesh = mfem.Mesh(2, 3, 1, 0, 2)
for j in range(3):
mesh.AddVertex(tri_v[j])
for j in range(1):
mesh.AddTri(tri_e[j], 11)
mesh.FinalizeTriMesh(1,1, True)
elif gtype == mfem.Geometry.SQUARE:
mesh = mfem.Mesh(2, 4, 1, 0, 2)
for j in range(4):
mesh.AddVertex(quad_v[j])
for j in range(1):
mesh.AddQuad(quad_e[j], 11)
mesh.FinalizeQuadMesh(1,1, True)
elif gtype == mfem.Geometry.SEGMENT:
mesh = mfem.Mesh(1, 2, 1, 0, 1)
for j in range(2):
mesh.AddVertex(seg_v[j])
for j in range(1):
seg = mfem.Segment(seg_e[j], j+1)
mesh.AddElement(seg)
seg.thisown = False
mesh.FinalizeTopology()
mesh.Finalize(False, False)
fec_type = mfem.H1_FECollection
fe_coll = fec_type(1, 2)
fes = mfem.FiniteElementSpace(mesh, fe_coll, 2)
el = fes.GetFE(0)
npt = Geom.GetVertices(gtype).GetNPoints()
RefG = GR.Refine(gtype, refine)
shape = mfem.Vector(el.GetDof())
ir = RefG.RefPts
shapes =[]
for i in range(ir.GetNPoints()):
el.CalcShape(ir.IntPoint(i), shape)
shapes.append(shape.GetDataArray().copy())
w = np.vstack(shapes)
globals()['weight'][(refine, gtype)] = w
return w
def straight_line_mesh(lengths,
nsegs,
filename='',
refine=False,
fix_orientation=False,
sdim=3,
x0=0.0):
Nvert = np.sum(nsegs) + 1
Nelem = np.sum(nsegs)
Nbdrelem = len(lengths) + 1
mesh = mfem.Mesh(1, Nvert, Nelem, Nbdrelem, sdim)
ivert = {}
L = np.hstack(([0], np.cumsum(lengths))).astype(float)
P = np.hstack(([0], np.cumsum(nsegs))).astype(int)
X = [np.linspace(L[i], L[i + 1], n + 1)[1:] for i, n in enumerate(nsegs)]
X = np.hstack(([0], np.hstack(X)))
A = np.hstack([[i + 1] * n for i, n in enumerate(nsegs)])
for k, i in enumerate(P):
ptx = mfem.Point(i)
ptx.SetAttribute(k + 1)
mesh.AddBdrElement(ptx)
ptx.thisown = False
for i in range(X.shape[0] - 1):
seg = mfem.Segment((i, i + 1), A[i])
mesh.AddElement(seg)
seg.thisown = False
for i in range(X.shape[0]):
pt = [0] * sdim
pt[0] = X[i] + x0
mesh.AddVertex(pt)
mesh.FinalizeTopology()
mesh.Finalize(refine, fix_orientation)
if filename != '':
mesh.PrintToFile(filename, 8)
return mesh
def _fill_mesh_elements(omesh, vtx, indices, nverts, attrs, base):
cnverts = np.hstack([0, np.cumsum(nverts)])
for i, a in enumerate(attrs):
iv = indices[cnverts[i]:cnverts[i + 1]]
if base[i] == 1: # segment
el = mfem.Segment()
el.SetAttribute(a)
el.SetVertices(list(iv))
el.thisown = False
omesh.AddElement(el)
elif base[i] == 2: # triangle
omesh.AddTri(list(iv), a)
elif base[i] == 3: # quad
omesh.AddQuad(list(iv), a)
elif base[i] == 4: # tet
omesh.AddTet(list(iv), a)
elif base[i] == 5: # hex
omesh.AddHex(list(iv), a)
else:
assert False, "unsupported base geometry: " + str(base[i])