# Source code for pacman.model.graphs.abstract_vertex

```
# Copyright (c) 2016 The University of Manchester
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import Optional
from pacman.exceptions import PacmanConfigurationException
from pacman.model.graphs.common import ChipAndCore
class AbstractVertex(object):
"""
A vertex in a graph.
"""
__slots__ = (
# Indicates if the Vertex has been added to a graph
"_added_to_graph",
# Label for the vertex. Changable until added to graph
"_label",
# the x, y (and p) this vertex MUST be placed on
"_fixed_location")
def __init__(self, label: Optional[str] = None):
"""
:param str label: The optional name of the vertex
"""
self._label = label
self._added_to_graph = False
self._fixed_location: Optional[ChipAndCore] = None
@property
def label(self) -> Optional[str]:
"""
The current label to the vertex.
This label could change when the vertex is added to the graph.
:rtype: str
"""
return self._label
[docs]
def set_label(self, label: str):
"""
Changes the label for a vertex *not yet added* to a graph.
:param str label: new value for the label
:raises PacmanConfigurationException:
If there is an attempt to change the label once the vertex has
been added to a graph
"""
if self._added_to_graph:
raise PacmanConfigurationException(
"As Labels are also IDs they can not be changed.")
self._label = label
[docs]
def setAddedToGraph(self) -> None:
"""
Records that the vertex has been added to a graph.
:raises PacmanConfigurationException:
If there is an attempt to add the same vertex more than once
"""
self._added_to_graph = True
[docs]
def has_been_added_to_graph(self) -> bool:
"""
State if the vertex has been added to the graph or not
"""
return self._added_to_graph
[docs]
def get_fixed_location(self) -> Optional[ChipAndCore]:
"""
The x, y and possibly p the vertex *must* be placed on.
Typically `None`! Does not have the value of a normal placements.
Used instead of `ChipAndCoreConstraint`.
:rtype: None or ~pacman.model.graphs.common.ChipAndCore
"""
return self._fixed_location
[docs]
def set_fixed_location(self, x: int, y: int, p: Optional[int] = None):
"""
Set the location where the vertex must be placed.
.. note::
If called, must be called prior to the placement algorithms.
:param int x: X coordinate of fixed location
:param int y: Y coordinate of fixed location
:param int p: Processor ID of fixed location
:raises PacmanConfigurationException:
If a fixed location has already been set to a different location.
"""
fixed_location = ChipAndCore(x, y, p)
if self._fixed_location is not None:
if fixed_location == self._fixed_location:
return
raise PacmanConfigurationException(
"Once set to a value fixed_location can not be changed")
self._fixed_location = fixed_location
```