org.opencores.placement
Class PrePlacement

java.lang.Object
  |
  +--org.opencores.placement.PrePlacement

public class PrePlacement

extends java.lang.Object

This algorithm tries to arrange graph nodes similarly to graph drawing algorithms. Nodes may overlap and they are placed in RxR space. Also this class contains some preplacement functions, that are based on RxR placement. After preplacement we have valid placement. Annealing uses two forces - temperature and distancing force. First nets acts like elastics and tries to approach nodes together, on the other hand nodes are distanced by the power of distancing force. Preplacement consist of three steps: - preplacement of SPCs - preplacement of GPCs - preplacement of ports

Field Summary

private Graph	g graph representation we are working on
int	nGPC Number of GPCs detected by preplacement
int	nInputs Number of total LUT inputs.
int	nIOC Number of Ports detected by preplacement
private int[]	pos position array, knowing number of LUTs at that position
java.util.Vector	vnl vector, that contains all GPCs

Constructor Summary

PrePlacement(Graph g)
Initializes RxR placement.

Method Summary

private float	portDist(float x, float y, int pi) returns manhattan distance between specified position (x,y) and port with index pi.
void	prePlacement() Does preplacement.
void	prePlacementGPC() Assigns valid positions for GPCs.
void	prePlacementIOC() Assigns valid positions for IOC.
void	setGraph(Graph g) Changes working graph.

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, registerNatives, toString, wait, wait, wait

Field Detail

g

private Graph g

graph representation we are working on

nGPC

public int nGPC

Number of GPCs detected by preplacement

nIOC

public int nIOC

Number of Ports detected by preplacement

nInputs

public int nInputs

Number of total LUT inputs.

vnl

public java.util.Vector vnl

vector, that contains all GPCs

pos

private int[] pos

position array, knowing number of LUTs at that position

Constructor Detail

PrePlacement

public PrePlacement(Graph g)

Initializes RxR placement.

Parameters:

g - graph to do placement on.

Method Detail

setGraph

public void setGraph(Graph g)

Changes working graph.

Parameters:

g - graph to work on

See Also:

Graph

prePlacementGPC

public void prePlacementGPC()

Assigns valid positions for GPCs. This placement is improved by main SA placement.

prePlacementIOC

public void prePlacementIOC()

Assigns valid positions for IOC. This placement is improved by main SA placement.

portDist

private float portDist(float x,
                       float y,
                       int pi)

returns manhattan distance between specified position (x,y) and port with index pi. Ports are arranged: {(0..X-1,0),(0..X-1,Y-1),(0,0..Y-1),(X-1,0..Y-1)}

Parameters:

x - x position

y - y position

pi - port index

Returns:

manhattan distance

prePlacement

public void prePlacement()

Does preplacement.

See Also:

prePlacementGPC, NOTE: Netlist must be mapped first.