org.opencores.placement
Class RxRPlacement

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

public class RxRPlacement

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

int	curStep Current step number.
boolean	done true if final solution was found.
private static float	DONE_FACTOR process terminates when change is small enough
float	energy Current placement quality.
private static float	FINAL_FORCE force flow definition (linear)
private static float	FINAL_TEMP temperature flow definition (linear)
float	force force, that distances nodes
private Graph	g graph representation we are working on
private java.util.Vector	groupList used internally to store groups
private static float	INIT_FORCE force flow definition (linear)
private static float	INIT_TEMP temperature flow definition (linear)
private static float	MIN_DIST minimum allowed distance between nodes
int	nGPC Number of GPCs detected by preplacement
int	nPorts Number of Ports detected by preplacement
int	nSPC Number of SPCs detected by preplacement
private static int	NUM_STEPS number of annealing steps - temp and force is linearly interpolated
private int[]	pos position array, knowing number of LUTs at that position
private float	prevEnergy Previous (from previous step) placement quality.
float	temperature current annealing temperature
java.util.Vector	vna vector that contains all placed adders
java.util.Vector	vnl vector, that contains all GPCs

Constructor Summary

RxRPlacement(Graph g)
Initializes RxR placement.

Method Summary

void	approach(float factor) approaches all connected nodes
void	distance(float factor) distances nodes, that are close together by factor
private int	distribute(NodeSPC n) Distributes adders by force (no nearby free column available)
void	doStep() does one step of simulated annealing.
private float	portDist(float x, float y, int pi) returns manhattan distance between specified position (x,y) and port with index pi.
void	prePlacement(SPCMap ma) Does preplacement.
void	prePlacementGPC() Assigns valid positions for GPCs.
void	prePlacementPort() Assigns valid positions for Ports.
void	prePlacementSPC(SPCMap ma) Place adders (SPCs), based on RxR placement.
void	setGraph(Graph g) Changes working graph.
void	zoom() zooms all nodes to fit onto arhitecture rectangle

Methods inherited from class java.lang.Object

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

Field Detail

MIN_DIST

private static final float MIN_DIST

minimum allowed distance between nodes

INIT_TEMP

private static final float INIT_TEMP

temperature flow definition (linear)

FINAL_TEMP

private static final float FINAL_TEMP

temperature flow definition (linear)

INIT_FORCE

private static final float INIT_FORCE

force flow definition (linear)

FINAL_FORCE

private static final float FINAL_FORCE

force flow definition (linear)

DONE_FACTOR

private static final float DONE_FACTOR

process terminates when change is small enough

NUM_STEPS

private static final int NUM_STEPS

number of annealing steps - temp and force is linearly interpolated

g

private Graph g

graph representation we are working on

temperature

public float temperature

current annealing temperature

force

public float force

force, that distances nodes

energy

public float energy

Current placement quality.

prevEnergy

private float prevEnergy

Previous (from previous step) placement quality.

curStep

public int curStep

Current step number.

done

public boolean done

true if final solution was found.

nSPC

public int nSPC

Number of SPCs detected by preplacement

nGPC

public int nGPC

Number of GPCs detected by preplacement

nPorts

public int nPorts

Number of Ports detected by preplacement

vna

public java.util.Vector vna

vector that contains all placed adders

groupList

private java.util.Vector groupList

used internally to store groups

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

RxRPlacement

public RxRPlacement(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

approach

public void approach(float factor)

approaches all connected nodes

Parameters:

factor - attraction strength

distance

public void distance(float factor)

distances nodes, that are close together by factor

Parameters:

factor - repulsive strength

zoom

public void zoom()

zooms all nodes to fit onto arhitecture rectangle

doStep

public void doStep()

does one step of simulated annealing. This function sets done flag when done.

prePlacementSPC

public void prePlacementSPC(SPCMap ma)

Place adders (SPCs), based on RxR placement. Place them based on their .fx sequentially. Important nets have a priority. This is just a preplacement. Adders are also optimized in main SA algorithm

Parameters:

ma - mapped adders NOTE: Netlist must be mapped first.

See Also:

SPCMap

distribute

private int distribute(NodeSPC n)

Distributes adders by force (no nearby free column available)

Parameters:

n - NodeSPC to distribute

Returns:

(csize) number of actually place elements

prePlacementGPC

public void prePlacementGPC()

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

prePlacementPort

public void prePlacementPort()

Assigns valid positions for Ports. 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(SPCMap ma)

Does preplacement.

Parameters:

ma - mapped adders

See Also:

prePlacementGPC, prePlacementSPC, NOTE: Netlist must be mapped first., org.opencores.mapping.Adders