mirror of https://github.com/VLSIDA/OpenRAM.git
77 lines
2.3 KiB
Python
77 lines
2.3 KiB
Python
# See LICENSE for licensing information.
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#
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# Copyright (c) 2016-2023 Regents of the University of California, Santa Cruz
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# All rights reserved.
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#
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from openram.base.vector import vector
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from openram.base.vector3d import vector3d
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from openram.tech import drc
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class hanan_node:
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""" This class represents a node on the Hanan graph. """
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# This is used to assign unique ids to nodes
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next_id = 0
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def __init__(self, center):
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self.id = hanan_node.next_id
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hanan_node.next_id += 1
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if isinstance(center, vector3d):
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self.center = center
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else:
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self.center = vector3d(center)
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self.neighbors = []
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def add_neighbor(self, other):
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""" Connect two nodes. """
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if other not in self.neighbors:
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self.neighbors.append(other)
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other.neighbors.append(self)
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def remove_neighbor(self, other):
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""" Disconnect two nodes. """
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if other in self.neighbors:
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self.neighbors.remove(other)
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other.neighbors.remove(self)
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def remove_all_neighbors(self):
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""" Disconnect all current neighbors. """
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for neighbor in self.neighbors:
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self.neighbors.remove(neighbor)
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neighbor.neighbors.remove(self)
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def get_direction(self, b):
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""" Return the direction of path from a to b. """
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horiz = self.center.x == b.center.x
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vert = self.center.y == b.center.y
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return (horiz, vert)
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def get_edge_cost(self, other, prev_node=None):
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""" Get the cost of going from this node to the other node. """
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if other in self.neighbors:
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is_vertical = self.center.x == other.center.x
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layer_dist = self.center.distance(other.center)
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# Edge is on non-preferred direction
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if is_vertical != bool(self.center.z):
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layer_dist *= 2
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# Wire bends towards non-preferred direction
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# NOTE: Adding a fixed cost prevents multiple dog-legs in
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# non-preferred direction
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if prev_node and self.get_direction(prev_node) != self.get_direction(other):
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layer_dist += drc["grid"]
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via_dist = abs(self.center.z - other.center.z) * 2
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return layer_dist + via_dist
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return float("inf")
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