def create_square_element(mesh: Mesh, finite_element_field: Field,
node_coordinate_set):
"""
Create a single square 2-D finite element using the supplied
finite element field and sequence of 4 n-D node coordinates.
:param mesh: The Zinc Mesh to create elements in.
:param finite_element_field: Zinc FieldFiniteElement to interpolate on element.
:param node_coordinate_set: Sequence of 4 coordinates each with as many components as finite element field.
:return: None
"""
assert mesh.getDimension() == 2
assert finite_element_field.castFiniteElement().isValid()
assert len(node_coordinate_set) == 4
fieldmodule = finite_element_field.getFieldmodule()
nodeset = fieldmodule.findNodesetByFieldDomainType(Field.DOMAIN_TYPE_NODES)
node_template = nodeset.createNodetemplate()
node_template.defineField(finite_element_field)
element_template = mesh.createElementtemplate()
element_template.setElementShapeType(Element.SHAPE_TYPE_SQUARE)
linear_basis = fieldmodule.createElementbasis(
2, Elementbasis.FUNCTION_TYPE_LINEAR_LAGRANGE)
eft = mesh.createElementfieldtemplate(linear_basis)
element_template.defineField(finite_element_field, -1, eft)
field_cache = fieldmodule.createFieldcache()
with ChangeManager(fieldmodule):
node_identifiers = []
for node_coordinate in node_coordinate_set:
node = nodeset.createNode(-1, node_template)
node_identifiers.append(node.getIdentifier())
field_cache.setNode(node)
finite_element_field.assignReal(field_cache, node_coordinate)
element = mesh.createElement(-1, element_template)
element.setNodesByIdentifier(eft, node_identifiers)
fieldmodule.defineAllFaces()
def field_is_managed_coordinates(field_in: Field):
"""
Conditional function returning True if the field is Finite Element
type with 3 components, and is managed.
"""
return field_in.castFiniteElement().isValid() and (
field_in.getNumberOfComponents() == 3) and field_in.isManaged()
def create_fields_transformations(coordinates: Field,
rotation_angles=None,
scale_value=1.0,
translation_offsets=None):
"""
Create constant fields for rotation, scale and translation containing the supplied
values, plus the transformed coordinates applying them in the supplied order.
:param coordinates: The coordinate field to scale, 3 components.
:param rotation_angles: List of euler angles, length = number of components.
See create_field_euler_angles_rotation_matrix.
:param scale_value: Scalar to multiply all components of coordinates.
:param translation_offsets: List of offsets, length = number of components.
:return: 4 fields: transformedCoordinates, rotation, scale, translation
"""
if rotation_angles is None:
rotation_angles = [0.0, 0.0, 0.0]
if translation_offsets is None:
translation_offsets = [0.0, 0.0, 0.0]
components_count = coordinates.getNumberOfComponents()
assert (components_count == 3) and (len(rotation_angles) == components_count) and isinstance(scale_value, float) \
and (len(translation_offsets) == components_count), "createTransformationFields. Invalid arguments"
fieldmodule = coordinates.getFieldmodule()
with ChangeManager(fieldmodule):
# scale, translate and rotate model, in that order
rotation = fieldmodule.createFieldConstant(rotation_angles)
scale = fieldmodule.createFieldConstant(scale_value)
translation = fieldmodule.createFieldConstant(translation_offsets)
rotation_matrix = create_field_euler_angles_rotation_matrix(
fieldmodule, rotation)
rotated_coordinates = fieldmodule.createFieldMatrixMultiply(
components_count, rotation_matrix, coordinates)
transformed_coordinates = rotated_coordinates * scale + translation
assert transformed_coordinates.isValid()
return transformed_coordinates, rotation, scale, translation
def field_is_managed_real_1_to_3_components(field_in: Field):
"""
Conditional function returning True if the field is real-valued
with up to 3 components, and is managed.
"""
return (field_in.getValueType() == Field.VALUE_TYPE_REAL) and \
(field_in.getNumberOfComponents() <= 3) and field_in.isManaged()
def createFieldsTransformations(coordinates: Field, rotation_angles=None, scale_value=1.0, \
translation_offsets=None, translation_scale_factor=1.0):
"""
Create constant fields for rotation, scale and translation containing the supplied
values, plus the transformed coordinates applying them in the supplied order.
:param coordinates: The coordinate field to scale, 3 components.
:param rotation_angles: List of euler angles, length = number of components.
See create_field_euler_angles_rotation_matrix.
:param scale_value: Scalar to multiply all components of coordinates.
:param translation_offsets: List of offsets, length = number of components.
:param translation_scale_factor: Scaling to multiply translation by so it's magnitude can remain
close to other parameters for rotation (radians) and scale (assumed close to unit).
:return: 4 fields: transformedCoordinates, rotation, scale, translation
"""
if rotation_angles is None:
rotation_angles = [0.0, 0.0, 0.0]
if translation_offsets is None:
translation_offsets = [0.0, 0.0, 0.0]
components_count = coordinates.getNumberOfComponents()
assert (components_count == 3) and (len(rotation_angles) == components_count) and isinstance(scale_value, float) \
and (len(translation_offsets) == components_count), "createFieldsTransformations. Invalid arguments"
fieldmodule = coordinates.getFieldmodule()
with ChangeManager(fieldmodule):
# Rotate, scale, and translate model, in that order
rotation = fieldmodule.createFieldConstant(rotation_angles)
scale = fieldmodule.createFieldConstant(scale_value)
translation = fieldmodule.createFieldConstant(translation_offsets)
rotation_matrix = create_field_euler_angles_rotation_matrix(
fieldmodule, rotation)
rotated_coordinates = fieldmodule.createFieldMatrixMultiply(
components_count, rotation_matrix, coordinates)
transformed_coordinates = rotated_coordinates*scale + (translation if (translation_scale_factor == 1.0) else \
translation*fieldmodule.createFieldConstant([ translation_scale_factor ]*components_count))
assert transformed_coordinates.isValid()
return transformed_coordinates, rotation, scale, translation
def field_is_managed_coordinates(field_in: Field):
"""
Conditional function returning True if the field is Finite Element
type, with coordinate type attribute, up to 3 components, and is managed.
"""
return (field_in is not None) and field_in.isManaged() and\
(field_in.getNumberOfComponents() <= 3) and\
field_in.castFiniteElement().isValid() and field_in.isTypeCoordinate()
def setModelCoordinatesField(self, modelCoordinatesField: Field):
finiteElementField = modelCoordinatesField.castFiniteElement()
assert finiteElementField.isValid() and (
finiteElementField.getNumberOfComponents() == 3)
self._modelCoordinatesField = finiteElementField
self._modelCoordinatesFieldName = modelCoordinatesField.getName()
modelReferenceCoordinatesFieldName = "reference_" + self._modelCoordinatesField.getName(
)
orphanFieldByName(self._fieldmodule,
modelReferenceCoordinatesFieldName)
self._modelReferenceCoordinatesField = createFieldFiniteElementClone(
self._modelCoordinatesField, modelReferenceCoordinatesFieldName)
self._updateMarkerCoordinatesField()
self._updateMarkerDataLocationCoordinatesField()
def create_fields_displacement_gradients(coordinates: Field,
reference_coordinates: Field,
mesh: Mesh):
"""
:return: 1st and 2nd displacement gradients of (coordinates - referenceCoordinates) w.r.t. referenceCoordinates.
"""
assert (coordinates.getNumberOfComponents()
== 3) and (reference_coordinates.getNumberOfComponents() == 3)
fieldmodule = mesh.getFieldmodule()
dimension = mesh.getDimension()
with ChangeManager(fieldmodule):
if dimension == 3:
u = coordinates - reference_coordinates
displacement_gradient = fieldmodule.createFieldGradient(
u, reference_coordinates)
displacement_gradient2 = fieldmodule.createFieldGradient(
displacement_gradient, reference_coordinates)
elif dimension == 2:
# Note this needs improvement as missing cross terms
# assume xi directions are approximately normal;
# effect is to penalise elements where this is not so, which is also desired
dX_dxi1 = fieldmodule.createFieldDerivative(
reference_coordinates, 1)
dX_dxi2 = fieldmodule.createFieldDerivative(
reference_coordinates, 2)
dx_dxi1 = fieldmodule.createFieldDerivative(coordinates, 1)
dx_dxi2 = fieldmodule.createFieldDerivative(coordinates, 2)
dS1_dxi1 = fieldmodule.createFieldMagnitude(dX_dxi1)
dS2_dxi2 = fieldmodule.createFieldMagnitude(dX_dxi2)
du_dS1 = (dx_dxi1 - dX_dxi1) / dS1_dxi1
du_dS2 = (dx_dxi2 - dX_dxi2) / dS2_dxi2
displacement_gradient = fieldmodule.createFieldConcatenate(
[du_dS1, du_dS2])
# curvature:
d2u_dSdxi1 = fieldmodule.createFieldDerivative(
displacement_gradient, 1)
d2u_dSdxi2 = fieldmodule.createFieldDerivative(
displacement_gradient, 2)
displacement_gradient2 = fieldmodule.createFieldConcatenate(
[d2u_dSdxi1 / dS1_dxi1, d2u_dSdxi2 / dS2_dxi2])
else: # dimension == 1
dX_dxi1 = fieldmodule.createFieldDerivative(
reference_coordinates, 1)
dx_dxi1 = fieldmodule.createFieldDerivative(coordinates, 1)
dS1_dxi1 = fieldmodule.createFieldMagnitude(dX_dxi1)
displacement_gradient = (dx_dxi1 - dX_dxi1) / dS1_dxi1
# curvature:
displacement_gradient2 = fieldmodule.createFieldDerivative(
displacement_gradient, 1) / dS1_dxi1
return displacement_gradient, displacement_gradient2
def assign_field_parameters(target_field: Field, source_field: Field):
"""
Copy parameters from sourceField to targetField.
Currently only works for node parameters.
"""
field_assignment = target_field.createFieldassignment(source_field)
field_assignment.assign()
def setSelectHighlightGroup(self, group: FieldGroup):
"""
Select and highlight objects in the group.
:param group: FieldGroup to select, or None to clear selection.
"""
fieldmodule = self.getFieldmodule()
with ChangeManager(fieldmodule):
scene = self.getScene()
# can't use SUBELEMENT_HANDLING_MODE_FULL as some groups have been tweaked to omit some faces
selectionGroup = get_scene_selection_group(
scene,
subelementHandlingMode=FieldGroup.SUBELEMENT_HANDLING_MODE_NONE
)
if group:
if selectionGroup:
selectionGroup.clear()
else:
selectionGroup = create_scene_selection_group(
scene,
subelementHandlingMode=FieldGroup.
SUBELEMENT_HANDLING_MODE_NONE)
group_add_group_elements(selectionGroup,
group,
highest_dimension_only=False)
for fieldDomainType in (Field.DOMAIN_TYPE_NODES,
Field.DOMAIN_TYPE_DATAPOINTS):
group_add_group_nodes(
selectionGroup, group,
fieldmodule.findNodesetByFieldDomainType(
fieldDomainType))
else:
if selectionGroup:
selectionGroup.clear()
scene.setSelectionField(Field())
def isoscalarFieldChanged(self, index):
if self._graphics:
contours = self._graphics.castContours()
if contours.isValid():
isoscalarField = self.ui.isoscalar_field_chooser.getField()
if not isoscalarField:
isoscalarField = Field()
contours.setIsoscalarField(isoscalarField)
def _setupGroupSettingWidgets(self):
"""
Set up group setting widgets and display values from fitter object.
"""
self._ui.groupSettings_fieldChooser.setRegion(self._fitter.getRegion())
self._ui.groupSettings_fieldChooser.setNullObjectName("-")
self._ui.groupSettings_fieldChooser.setConditional(field_is_managed_group)
self._ui.groupSettings_fieldChooser.setField(Field())
def getNodesetConditionalSize(nodeset: Nodeset, conditionalField: Field):
"""
:return: Number of objects in nodeset for which conditionalField is True.
"""
assert conditionalField.getNumberOfComponents() == 1
fieldmodule = conditionalField.getFieldmodule()
fieldcache = fieldmodule.createFieldcache()
nodeiterator = nodeset.createNodeiterator()
size = 0
node = nodeiterator.next()
while node.isValid():
fieldcache.setNode(node)
result, value = conditionalField.evaluateReal(fieldcache, 1)
if value != 0.0:
size += 1
node = nodeiterator.next()
return size
def labelFieldChanged(self, index):
if self._graphics:
pointattributes = self._graphics.getGraphicspointattributes()
if pointattributes.isValid():
labelField = self.ui.label_field_chooser.getField()
if not labelField:
labelField = Field()
pointattributes.setLabelField(labelField)
def pointOrientationScaleFieldChanged(self, index):
if self._graphics:
pointattributes = self._graphics.getGraphicspointattributes()
if pointattributes.isValid():
orientationScaleField = self.ui.point_orientation_scale_field_chooser.getField(
)
if not orientationScaleField:
orientationScaleField = Field()
pointattributes.setOrientationScaleField(orientationScaleField)
def lineOrientationScaleFieldChanged(self, index):
if self._graphics:
lineattributes = self._graphics.getGraphicslineattributes()
if lineattributes.isValid():
orientationScaleField = self.ui.line_orientation_scale_field_chooser.getField(
)
if not orientationScaleField:
orientationScaleField = Field()
lineattributes.setOrientationScaleField(orientationScaleField)
def streamVectorFieldChanged(self, index):
if self._graphics:
streamlines = self._graphics.castStreamlines()
if streamlines.isValid():
streamVectorField = self.ui.stream_vector_field_chooser.getField(
)
if not streamVectorField:
streamVectorField = Field()
streamlines.setStreamVectorField(streamVectorField)
def coordinateFieldChanged(self, index):
'''
An item was selected at index in coordinate field chooser widget
'''
if self._graphics:
coordinateField = self.ui.coordinate_field_chooser.getField()
if coordinateField:
self._graphics.setCoordinateField(coordinateField)
else:
self._graphics.setCoordinateField(Field())
def clearSelection(self):
"""
If there is a selection group, clears it and removes it from scene.
"""
selectionGroup = self.getSelectionGroup()
if selectionGroup is not None:
selectionGroup.clear()
selectionGroup = Field() # NULL
scene = self._sceneviewer.getScene()
scene.setSelectionField(selectionGroup)
def get_node_name_centres(nodeset: Nodeset, coordinates_field: Field,
name_field: Field):
"""
Find mean locations of node coordinate with the same names.
:param nodeset: Zinc Nodeset or NodesetGroup to search.
:param coordinates_field: The coordinate field to evaluate.
:param name_field: The name field to match.
:return: Dict of names -> coordinates.
"""
components_count = coordinates_field.getNumberOfComponents()
fieldmodule = nodeset.getFieldmodule()
fieldcache = fieldmodule.createFieldcache()
name_records = {} # name -> (coordinates, count)
nodeiter = nodeset.createNodeiterator()
node = nodeiter.next()
while node.isValid():
fieldcache.setNode(node)
name = name_field.evaluateString(fieldcache)
coordinates_result, coordinates = coordinates_field.evaluateReal(
fieldcache, components_count)
if name and (coordinates_result == RESULT_OK):
name_record = name_records.get(name)
if name_record:
name_centre = name_record[0]
for c in range(components_count):
name_centre[c] += coordinates[c]
name_record[1] += 1
else:
name_records[name] = [coordinates, 1]
node = nodeiter.next()
# divide centre coordinates by count
name_centres = {}
for name in name_records:
name_record = name_records[name]
name_count = name_record[1]
name_centre = name_record[0]
if name_count > 1:
scale = 1.0 / name_count
for c in range(components_count):
name_centre[c] *= scale
name_centres[name] = name_centre
return name_centres
def reset(self):
self._node = None
self._graphics = None
self._coordinateField = None
self._orientationField = None
self._glyphCentre = [0.0, 0.0, 0.0]
self._glyphSize = [0.0, 0.0, 0.0]
self._glyphScaleFactors = [0.0, 0.0, 0.0]
self._variableScaleField = Field()
self._nearestElement = None
self._elementCoordinateField = None
self._createCoordinatesField = None
def create_field_finite_element_clone(source_field: Field,
name: str,
managed=False) -> FieldFiniteElement:
"""
Copy an existing Finite Element Field to a new field of supplied name.
Note: does not handle time-varying parameters.
New field is not managed by default.
:param source_field: Zinc finite element field to copy.
:param name: The name of the new field, asserts that no field of that name exists.
:param managed: Managed state of field created here.
:return: New identically defined field with supplied name.
"""
assert source_field.castFiniteElement().isValid(), \
"opencmiss.utils.zinc.field.createFieldFiniteElementClone. Not a Zinc finite element field"
fieldmodule = source_field.getFieldmodule()
field = fieldmodule.findFieldByName(name)
assert not field.isValid(
), "opencmiss.utils.zinc.field.createFieldFiniteElementClone. Target field name is in use"
with ChangeManager(fieldmodule):
# Zinc needs a function to do this efficiently; currently serialise to string, replace field name and reload!
source_name = source_field.getName()
region = fieldmodule.getRegion()
sir = region.createStreaminformationRegion()
srm = sir.createStreamresourceMemory()
sir.setFieldNames([source_name])
region.write(sir)
result, buffer = srm.getBuffer()
# small risk of modifying other text here:
source_bytes = bytes(") " + source_name + ",", "utf-8")
target_bytes = bytes(") " + name + ",", "utf-8")
buffer = buffer.replace(source_bytes, target_bytes)
sir = region.createStreaminformationRegion()
sir.createStreamresourceMemoryBuffer(buffer)
result = region.read(sir)
assert result == RESULT_OK
# note currently must have called endChange before field can be found
field = fieldmodule.findFieldByName(name).castFiniteElement()
field.setManaged(managed)
assert field.isValid()
return field
def create_field_mesh_integral(coordinates: Field, mesh: Mesh, number_of_points=3):
"""
Create a field integrating the coordinates to give scalar volume/area/length over
the mesh, depending on its dimension.
:param coordinates:
:param mesh:
:param number_of_points: Number of Gauss points.
:return: Field giving volume of coordinates field over mesh via Gaussian quadrature.
"""
fieldmodule = coordinates.getFieldmodule()
with ChangeManager(fieldmodule):
mesh_integral_field = fieldmodule.createFieldMeshIntegral(fieldmodule.createFieldConstant(1.0),
coordinates, mesh)
mesh_integral_field.setNumbersOfPoints(number_of_points)
return mesh_integral_field
def evaluate_field_nodeset_mean(field: Field, nodeset: Nodeset):
"""
:return: Mean of field over nodeset.
"""
fieldmodule = nodeset.getFieldmodule()
components_count = field.getNumberOfComponents()
with ChangeManager(fieldmodule):
mean_field = fieldmodule.createFieldNodesetMean(field, nodeset)
fieldcache = fieldmodule.createFieldcache()
result, mean_values = mean_field.evaluateReal(fieldcache,
components_count)
assert result == RESULT_OK
del mean_field
del fieldcache
return mean_values
def create_triangle_elements(mesh: Mesh, finite_element_field: Field,
element_node_set):
"""
Create a linear triangular element for every set of 3 local nodes in element_node_set.
:param mesh: The Zinc Mesh to create elements in.
:param finite_element_field: Zinc FieldFiniteElement to interpolate from nodes.
:param element_node_set: Sequence of 3 node identifiers for each element.
:return: None
"""
assert mesh.getDimension() == 2
assert finite_element_field.castFiniteElement().isValid()
fieldmodule = finite_element_field.getFieldmodule()
element_template = mesh.createElementtemplate()
element_template.setElementShapeType(Element.SHAPE_TYPE_TRIANGLE)
linear_basis = fieldmodule.createElementbasis(
2, Elementbasis.FUNCTION_TYPE_LINEAR_SIMPLEX)
eft = mesh.createElementfieldtemplate(linear_basis)
element_template.defineField(finite_element_field, -1, eft)
with ChangeManager(fieldmodule):
for element_nodes in element_node_set:
element = mesh.createElement(-1, element_template)
element.setNodesByIdentifier(eft, element_nodes)
fieldmodule.defineAllFaces()
def dataFieldChanged(self, index):
'''
An item was selected at index in data field chooser widget
'''
if self._graphics:
dataField = self.ui.data_field_chooser.getField()
if dataField:
scene = self._graphics.getScene()
scene.beginChange()
spectrum = self._graphics.getSpectrum()
if not spectrum.isValid():
spectrummodule = scene.getSpectrummodule()
spectrum = spectrummodule.getDefaultSpectrum()
self._graphics.setSpectrum(spectrum)
self._graphics.setDataField(dataField)
scene.endChange()
else:
self._graphics.setDataField(Field())
def evaluate_field_nodeset_range(field: Field, nodeset: Nodeset):
"""
:return: min, max range of field over nodes.
"""
fieldmodule = nodeset.getFieldmodule()
components_count = field.getNumberOfComponents()
with ChangeManager(fieldmodule):
min_field = fieldmodule.createFieldNodesetMinimum(field, nodeset)
max_field = fieldmodule.createFieldNodesetMaximum(field, nodeset)
fieldcache = fieldmodule.createFieldcache()
result, min_values = min_field.evaluateReal(fieldcache,
components_count)
assert result == RESULT_OK
result, max_values = max_field.evaluateReal(fieldcache,
components_count)
assert result == RESULT_OK
del min_field
del max_field
del fieldcache
return min_values, max_values
def evaluate_field_mesh_integral(field: Field, coordinates: Field, mesh: Mesh, number_of_points=4):
"""
Integrate value of a field over mesh using Gaussian Quadrature.
:param field: Field to integrate over mesh.
:param coordinates: Field giving spatial coordinates to integrate over.
:param mesh: The mesh or mesh group to integrate over.
:param number_of_points: Number of integration points in each dimension.
:return: Integral value.
"""
fieldmodule = mesh.getFieldmodule()
components_count = field.getNumberOfComponents()
with ChangeManager(fieldmodule):
integral = fieldmodule.createFieldMeshIntegral(field, coordinates, mesh)
integral.setNumbersOfPoints(number_of_points)
fieldcache = fieldmodule.createFieldcache()
result, value = integral.evaluateReal(fieldcache, components_count)
del integral
del fieldcache
assert result == RESULT_OK
return value
def create_field_euler_angles_rotation_matrix(fieldmodule: Fieldmodule,
euler_angles: Field) -> Field:
"""
From OpenCMISS-Zinc graphics_library.cpp, matrix transposed to row major.
Matrix is product RzRyRx, giving rotation about x, then y, then z with
positive angles rotating by right hand rule about axis.
:param fieldmodule: The fieldmodule to create the field in.
:param euler_angles: 3-component field of angles in radians, components:
0 = azimuth (about z)
1 = elevation (about y)
2 = roll (about x)
:return: 3x3 rotation matrix field suitable for pre-multiplying vector v
i.e. v' = Mv
"""
assert euler_angles.getNumberOfComponents() == 3
with ChangeManager(fieldmodule):
azimuth = fieldmodule.createFieldComponent(euler_angles, 1)
cos_azimuth = fieldmodule.createFieldCos(azimuth)
sin_azimuth = fieldmodule.createFieldSin(azimuth)
elevation = fieldmodule.createFieldComponent(euler_angles, 2)
cos_elevation = fieldmodule.createFieldCos(elevation)
sin_elevation = fieldmodule.createFieldSin(elevation)
roll = fieldmodule.createFieldComponent(euler_angles, 3)
cos_roll = fieldmodule.createFieldCos(roll)
sin_roll = fieldmodule.createFieldSin(roll)
minus_one = fieldmodule.createFieldConstant([-1.0])
cos_azimuth_sin_elevation = cos_azimuth * sin_elevation
sin_azimuth_sin_elevation = sin_azimuth * sin_elevation
matrix_components = [
cos_azimuth * cos_elevation,
cos_azimuth_sin_elevation * sin_roll - sin_azimuth * cos_roll,
cos_azimuth_sin_elevation * cos_roll + sin_azimuth * sin_roll,
sin_azimuth * cos_elevation,
sin_azimuth_sin_elevation * sin_roll + cos_azimuth * cos_roll,
sin_azimuth_sin_elevation * cos_roll - cos_azimuth * sin_roll,
minus_one * sin_elevation, cos_elevation * sin_roll,
cos_elevation * cos_roll
]
rotation_matrix = fieldmodule.createFieldConcatenate(matrix_components)
return rotation_matrix
def find_node_with_name(nodeset: Nodeset, name_field: Field, name):
"""
Get single node in nodeset with supplied name.
:param nodeset: Zinc Nodeset or NodesetGroup to search.
:param name_field: The name field to match.
:param name: The name to match in nameField.
:return: Node with name, or None if 0 or multiple nodes with name.
"""
fieldmodule = nodeset.getFieldmodule()
fieldcache = fieldmodule.createFieldcache()
nodeiter = nodeset.createNodeiterator()
node_with_name = None
node = nodeiter.next()
while node.isValid():
fieldcache.setNode(node)
temp_name = name_field.evaluateString(fieldcache)
if temp_name == name:
if node_with_name:
return None
node_with_name = node
node = nodeiter.next()
return node_with_name
