def TetVolume(nodeCoords, signed=False):
"""
Return the volume of the tetrahedron with the supplied node coordinates
"""
if optimise.DebuggingEnabled():
type = elements.ElementType(dim=len(nodeCoords[0]),
nodeCount=len(nodeCoords))
assert (type.GetElementTypeId() == elements.ELEMENT_TETRAHEDRON)
return SimplexVolume(nodeCoords, signed=signed)
def SimplexEdgeVectors(nodeCoords):
"""
Return the edge vectors for the tetrahedron with the supplied node coordinates
"""
type = elements.ElementType(dim=len(nodeCoords[0]),
nodeCount=len(nodeCoords))
assert (type.GetElementFamilyId() == elements.ELEMENT_FAMILY_SIMPLEX)
return [[nodeCoord[i] - nodeCoords[0][i] for i in range(type.GetDim())]
for nodeCoord in nodeCoords[1:]]
def SimplexIntegral(nodeCoords, nodeCoordVals):
"""
Integrate a P1 field over a simplex
"""
type = elements.ElementType(dim=len(nodeCoords[0]),
nodeCount=len(nodeCoords))
assert (type.GetElementFamilyId() == elements.ELEMENT_FAMILY_SIMPLEX)
assert (len(nodeCoordVals) == type.GetNodeCount())
integral = nodeCoordVals[0]
for val in nodeCoordVals[1:]:
integral += val
integral *= SimplexVolume(nodeCoords) / float(type.GetNodeCount())
return integral
def SimplexVolume(nodeCoords, signed=False):
"""
Return the volume of the simplex with the supplied node coordinates
"""
type = elements.ElementType(dim=len(nodeCoords[0]),
nodeCount=len(nodeCoords))
assert (type.GetElementFamilyId() == elements.ELEMENT_FAMILY_SIMPLEX)
volume = calc.Determinant(SimplexEdgeVectors(nodeCoords)) / calc.Factorial(
type.GetDim())
if signed:
return volume
else:
return abs(volume)
def WriteGid(mesh, filename):
"""
Write a GiD file with the given filename
"""
debug.dprint("Writing GiD mesh with filename " + filename)
fileHandle = open(filename, "w")
# Write the header
fileHandle.write(
utils.FormLine([
"MESH", "dimension",
mesh.GetDim(), "ElemType", "Unknown", "Nnode",
mesh.VolumeElementFixedNodeCount()
]))
# Write the nodes
fileHandle.write("Coordinates\n")
for i, nodeCoord in enumerate(mesh.GetNodeCoords()):
fileHandle.write(" " + utils.FormLine([i + 1, nodeCoord]))
fileHandle.write("end coordinates\n")
# Write the volume elements
fileHandle.write("Elements\n")
for i, element in enumerate(mesh.GetVolumeElements()):
# Note: GiD file indexes nodes from 1, Mesh s index nodes from 0
fileHandle.write(" " + utils.FormLine([
i + 1,
ToGidNodeOrder(
utils.OffsetList(element.GetNodes(), 1),
elements.ElementType(dim=mesh.GetDim(),
nodeCount=element.NodeCount()))
]))
fileHandle.write("end elements\n")
fileHandle.close()
debug.dprint("Finished writing GiD mesh")
return mesh
def ReadGid(filename):
"""
Read a GiD file with the given filename, and return it as a mesh
"""
debug.dprint("Reading GiD mesh with filename " + filename)
fileHandle = open(filename, "r")
# Read the header
header = fileHandle.readline()
lineSplit = header.split()
assert(lineSplit[0] == "MESH")
dimension = None
elemType = None
nnode = None
for i, word in enumerate(lineSplit[:len(lineSplit) - 1]):
if word == "dimension":
dimension = int(lineSplit[i + 1])
assert(dimension >= 0)
elif word == "ElemType":
elemType = lineSplit[i + 1]
elif word == "Nnode":
nnode = int(lineSplit[i + 1])
assert(nnode >= 0)
assert(not dimension is None)
assert(not elemType is None)
assert(not nnode is None)
debug.dprint("Dimension = " + str(dimension))
debug.dprint("Element type = " + elemType)
debug.dprint("Element nodes = " + str(nnode))
# Read the nodes
nodeCoords = []
line = fileHandle.readline()
index = 0
while len(line) > 0:
if line.strip() == "Coordinates":
line = fileHandle.readline()
while not line.strip() == "end coordinates":
assert(len(line) > 0)
index += 1
lineSplit = line.split()
assert(len(lineSplit) == 1 + dimension)
assert(int(lineSplit[0]) == index)
nodeCoords.append([float(coord) for coord in lineSplit[1:]])
line = fileHandle.readline()
break
line = fileHandle.readline()
debug.dprint("Nodes: " + str(index))
# Check for unused dimensions
lbound = [calc.Inf() for i in range(dimension)]
ubound = [-calc.Inf() for i in range(dimension)]
for nodeCoord in nodeCoords:
for i, val in enumerate(nodeCoord):
lbound[i] = min(lbound[i], val)
ubound[i] = max(ubound[i], val)
boundingBox = bounds.BoundingBox(lbound, ubound)
actualDimension = boundingBox.UsedDim()
if not dimension == actualDimension:
debug.deprint("Dimension suggested by bounds = " + str(actualDimension))
debug.deprint("Warning: Header dimension inconsistent with bounds")
dimension = actualDimension
coordMask = boundingBox.UsedDimCoordMask()
nodeCoords = [utils.MaskList(nodeCoord, coordMask) for nodeCoord in nodeCoords]
mesh = meshes.Mesh(dimension)
mesh.AddNodeCoords(nodeCoords)
fileHandle.seek(0)
# Read the volume elements
line = fileHandle.readline()
index = 0
while len(line) > 0:
if line.strip() == "Elements":
line = fileHandle.readline()
while not line.strip() == "end elements":
assert(len(line) > 0)
index += 1
lineSplit = line.split()
assert(len(lineSplit) == 1 + nnode)
assert(int(lineSplit[0]) == index)
# Note: GiD file indexes nodes from 1, Mesh s index nodes from 0
mesh.AddVolumeElement(elements.Element(nodes = FromGidNodeOrder([int(node) - 1 for node in lineSplit[1:]], elements.ElementType(dim = dimension, nodeCount = nnode))))
line = fileHandle.readline()
break
line = fileHandle.readline()
debug.dprint("Elements: " + str(index))
fileHandle.close()
debug.dprint("Finished reading GiD mesh")
return mesh