/// <summary>
/// Layout nodes based on their depth within the network.
///
/// Note 1.
/// Input nodes are defined as being at layer zero and we position them in their own layer at the
/// top of the layout area. Any other type of node (hidden or output) node not connected to is also
/// defined as being at layer zero, if such nodes exist then we place them into their own layout
/// layer to visually separate them from the input nodes.
///
/// Note 2.
/// Output nodes can be at a range of depths, but for clarity we position them all in their own layer
/// at the bottom of the layout area. A hidden node can have a depth greater than or equal to one or
/// more of the output nodes, to handle this case neatly we ensure that the output nodes are always
/// in a layer by themselves by creating an additional layer in the layout if necessary.
///
/// Note 3.
/// Hidden nodes are positioned into layers between the inputs and outputs based on their depth.
///
/// Note 4.
/// Empty layers are not possible in the underlying network because for there to be a layer N node it
/// must have a connection from a layer N-1 node. However, in cyclic networks the output nodes can be
/// source nodes, but we also always paint output nodes in their own layout layer at the bottom of the
/// layout area. Therefore if the only node at a given depth is an output node then the layout layer
/// can be empty. To handle this neatly we check for empty layout layers before invoking the layout logic.
/// </summary>
/// <param name="graph">The network/graph structure to be layed out.</param>
/// <param name="layoutArea">The area the structure is to be layed out on.</param>
public void Layout(IOGraph graph, Size layoutArea)
{
int inputCount = graph.InputNodeList.Count;
int outputCount = graph.OutputNodeList.Count;
int hiddenCount = graph.HiddenNodeList.Count;
//=== Stratify all nodes into layout layers, each layer keyed by depth value.
SortedDictionary<int,List<GraphNode>> layersByDepth = new SortedDictionary<int,List<GraphNode>>();
// Special case. Key all input nodes by depth -1. This places them as the first layer and distinct
// from all other nodes.
layersByDepth.Add(-1, graph.InputNodeList);
// Stratify hidden nodes into layers.
// Count hidden nodes in each layer.
int[] hiddenNodeCountByLayerArr = new int[graph.Depth];
for(int i=0; i<hiddenCount; i++) {
hiddenNodeCountByLayerArr[graph.HiddenNodeList[i].Depth]++;
}
// Allocate storage per layer.
for(int i=0; i<graph.Depth; i++)
{
int nodeCount = hiddenNodeCountByLayerArr[i];
if(0 != nodeCount) {
layersByDepth.Add(i, new List<GraphNode>(nodeCount));
}
}
// Put hidden nodes into layer lists.
for(int i=0; i<hiddenCount; i++)
{
GraphNode node = graph.HiddenNodeList[i];
layersByDepth[node.Depth].Add(node);
}
// Special case 2. Place output nodes in their own distinct layer at a depth one more than the max
// depth of the network. This places them as the last layer and distinct from all other nodes.
layersByDepth.Add(graph.Depth, graph.OutputNodeList);
//=== Layout.
// Calculate height of each layer. We divide the layout area height by the number of layers, but also
// define margins at the top and bottom of the view. To make best use of available height the margins
// are defined as a proportion of the layer height. Hence we have:
//
// ============================
// d - network depth.
// l - layer height.
// m - margin height (same height used for top and bottom margins).
// p - proportion of layer height that gives margin height.
// H - layout areas height
// ============================
//
// Derivation:
// ============================
// 1) l = (H-2m) / (d-1)
//
// 2) m = lp, therefore
//
// 3) l = (H-2pl) / (d-1), solve for l
//
// 4) l = H/(d-1) - 2pl/(d-1)
//
// 5) 1 = H/(d-1)l - 2p/(d-1)
//
// 6) H / (d-1)l = 1 + 2p/(d-1), inverting both sides gives
//
// 7) (d-1)l / H = 1/[ 1 + 2p/(d-1) ]
//
// 8) = (d-1) / ((d-1) + 2p)
//
// 9) = (d-1) / (d + 2p - 1), rearranging for l gives
//
// 10) l = H / (d + 2p - 1)
const float p = 0.33f;
const float p2 = 2f * p;
// Rounding will produce 'off by one' errors, e.g. all heights may not total heinght of layout area,
// but the effect is probably negligible on the quality of the layout.
int layoutLayerCount = layersByDepth.Count;
int l = (int)Math.Round((float)layoutArea.Height / ((float)layoutLayerCount + p2 - 1f));
int m = (int)Math.Round(l * p);
// Size struct to keep track of the area that bounds all nodes.
Size bounds = new Size(0,0);
// Assign a position to each node, one layer at a time.
int yCurrent = m;
foreach(List<GraphNode> layerNodeList in layersByDepth.Values)
{
// Calculate inter-node gap and margin width (we use the same principle as with the vertical layout of layers, see notes above).
int nodeCount = layerNodeList.Count;
float xIncr = (float)layoutArea.Width / ((float)nodeCount + p2 - 1f);
int xMargin = (int)Math.Round(xIncr * p);
// Loop nodes in layer; Assign position to each.
float xCurrent = xMargin;
for(int nodeIdx=0; nodeIdx < nodeCount; nodeIdx++, xCurrent += xIncr)
{
layerNodeList[nodeIdx].Position = new Point((int)xCurrent, yCurrent);
UpdateModelBounds(layerNodeList[nodeIdx], ref bounds);
}
// Increament y coord for next layer.
yCurrent += l;
}
// Store the bounds of the graph elements. Useful when drawing the graph.
graph.Bounds = bounds;
}
/// <summary>
/// Paints the provided IOGraph onto the provided GDI+ Graphics drawing surface.
/// </summary>
protected override void PaintNetwork(IOGraph graph, PaintState state)
{
// Invoke the base painting routine.
base.PaintNetwork(graph, state);
// Paint a legend for the activation functions.
PaintLegend(state);
}
/// <summary>
/// Paints the provided IOGraph onto the provided GDI+ Graphics drawing surface.
/// </summary>
protected override void PaintNetwork(IOGraph graph, PaintState state)
{
// Invoke the base painting routine.
base.PaintNetwork(graph, state);
// Paint a legend for the activation functions.
PaintLegend(state);
}
/// <summary>
/// Paints the provided IOGraph onto the provided GDI+ Graphics drawing surface.
/// </summary>
public void PaintNetwork(IOGraph graph, Graphics g, Rectangle viewportArea, float zoomFactor)
{
// Create a PaintState object. This holds all temporary state info for the painting routines.
// Pass the call on to the virtual PaintNetwork. This allows us to override a version of PaintNetwork
// that has access to a PaintState object.
PaintState state = new PaintState(g, viewportArea, zoomFactor, graph.ConnectionWeightRange);
PaintNetwork(graph, state);
}
/// <summary>
/// Paints the provided IOGraph onto the provided GDI+ Graphics drawing surface.
/// </summary>
public void PaintNetwork(IOGraph graph, Graphics g, Rectangle viewportArea, float zoomFactor)
{
// Create a PaintState object. This holds all temporary state info for the painting routines.
// Pass the call on to the virtual PaintNetwork. This allows us to override a version of PaintNetwork
// that has access to a PaintState object.
PaintState state = new PaintState(g, viewportArea, zoomFactor, graph.ConnectionWeightRange);
PaintNetwork(graph, state);
}
/// <summary>
/// Paints the provided IOGraph onto the current GDI+ Graphics drawing surface.
/// </summary>
protected virtual void PaintNetwork(IOGraph graph, PaintState state)
{
// Create per-node state info.
int hiddenNodeCount = graph.HiddenNodeList.Count;
int inputNodeCount = graph.InputNodeList.Count;
int outputNodeCount = graph.OutputNodeList.Count;
state._nodeStateDict = new Dictionary<GraphNode,ConnectionPointInfo>(hiddenNodeCount + inputNodeCount + outputNodeCount);
// Paint all connections. We do this first and paint nodes on top of the connections. This allows the
// slightly messy ends of the connections to be painted over by the nodes.
PaintConnections(graph.InputNodeList, state);
PaintConnections(graph.HiddenNodeList, state);
PaintConnections(graph.OutputNodeList, state);
// Paint all nodes. Painted over the top of connection endpoints.
PaintNodes(graph.InputNodeList, state);
PaintNodes(graph.HiddenNodeList, state);
PaintNodes(graph.OutputNodeList, state);
}
/// <summary>
/// Paints the provided IOGraph onto the current GDI+ Graphics drawing surface.
/// </summary>
protected virtual void PaintNetwork(IOGraph graph, PaintState state)
{
// Create per-node state info.
int hiddenNodeCount = graph.HiddenNodeList.Count;
int inputNodeCount = graph.InputNodeList.Count;
int outputNodeCount = graph.OutputNodeList.Count;
state._nodeStateDict = new Dictionary <GraphNode, ConnectionPointInfo>(hiddenNodeCount + inputNodeCount + outputNodeCount);
// Paint all connections. We do this first and paint nodes on top of the connections. This allows the
// slightly messy ends of the connections to be painted over by the nodes.
PaintConnections(graph.InputNodeList, state);
PaintConnections(graph.HiddenNodeList, state);
PaintConnections(graph.OutputNodeList, state);
// Paint all nodes. Painted over the top of connection endpoints.
PaintNodes(graph.InputNodeList, state);
PaintNodes(graph.HiddenNodeList, state);
PaintNodes(graph.OutputNodeList, state);
}
/// <summary>
/// Constructs with the provided graph painter and layout manager.
/// </summary>
public IOGraphViewportPainter(IOGraphPainter graphPainter, ILayoutManager layoutManager)
{
_graph = null;
_layoutManager = layoutManager;
_graphPainter = graphPainter;
}
/// <summary>
/// Constructs with the provided graph painter and a default layout manager.
/// </summary>
public IOGraphViewportPainter(IOGraphPainter graphPainter)
{
_graph = null;
_layoutManager = new DepthLayoutManager();
_graphPainter = graphPainter;
}
/// <summary>
/// Constructs with the provided graph painter and layout manager.
/// </summary>
public IOGraphViewportPainter(IOGraphPainter graphPainter, ILayoutManager layoutManager)
{
_graph = null;
_layoutManager = layoutManager;
_graphPainter = graphPainter;
}
/// <summary>
/// Constructs with the provided graph painter and a default layout manager.
/// </summary>
public IOGraphViewportPainter(IOGraphPainter graphPainter)
{
_graph = null;
_layoutManager = new DepthLayoutManager();
_graphPainter = graphPainter;
}
/// <summary>
/// Create an IOGraph that represents the structure described by the provided INetworkDefinition.
/// </summary>
public IOGraph CreateGraph(INetworkDefinition networkDef)
{
// Perform depth analysis of network.
NetworkDepthInfo depthInfo;
if (networkDef.IsAcyclic)
{
AcyclicNetworkDepthAnalysis depthAnalysis = new AcyclicNetworkDepthAnalysis();
depthInfo = depthAnalysis.CalculateNodeDepths(networkDef);
}
else
{
CyclicNetworkDepthAnalysis depthAnalysis = new CyclicNetworkDepthAnalysis();
depthInfo = depthAnalysis.CalculateNodeDepths(networkDef);
}
// Create an IOGraph, allocating storage for the node lists.
INodeList nodeList = networkDef.NodeList;
int nodeCount = nodeList.Count;
int inputCount = networkDef.InputNodeCount + 1; // + to count bias as an input layer node.
int outputCount = networkDef.OutputNodeCount;
int hiddenCount = nodeCount - (inputCount + outputCount);
IOGraph ioGraph = new IOGraph(inputCount, outputCount, hiddenCount, 0f, depthInfo._networkDepth);
// We also build a dictionary of nodes keyed by innovation ID. This is used later
// to assign connections to nodes.
Dictionary <uint, GraphNode> nodeDict = new Dictionary <uint, GraphNode>(nodeCount);
// Loop input nodes.
int idx = 0;
for (int i = 0; i < inputCount; i++, idx++)
{ // Create node, assign it a tag and add it to the node dictionary and the
// input node list of the IOGraph.
uint innovationId = nodeList[idx].Id;
GraphNode node = new GraphNode(innovationId.ToString());
node.AuxData = CreateGraphNodeAuxData(nodeList[idx]);
node.Depth = depthInfo._nodeDepthArr[idx];
nodeDict.Add(innovationId, node);
ioGraph.InputNodeList.Add(node);
}
// Loop output nodes.
for (int i = 0; i < outputCount; i++, idx++)
{ // Create node, assign it a tag and add it to the node dictionary and the
// output node list of the IOGraph.
uint innovationId = nodeList[idx].Id;
GraphNode node = new GraphNode(innovationId.ToString());
node.AuxData = CreateGraphNodeAuxData(nodeList[idx]);
node.Depth = depthInfo._nodeDepthArr[idx];
nodeDict.Add(innovationId, node);
ioGraph.OutputNodeList.Add(node);
}
// Loop hidden nodes.
for (; idx < nodeCount; idx++)
{ // Create node, assign it a tag and add it to the node dictionary and the
// hidden node list of the IOGraph.
uint innovationId = nodeList[idx].Id;
GraphNode node = new GraphNode(innovationId.ToString());
node.AuxData = CreateGraphNodeAuxData(nodeList[idx]);
node.Depth = depthInfo._nodeDepthArr[idx];
nodeDict.Add(innovationId, node);
ioGraph.HiddenNodeList.Add(node);
}
// Loop connections. Build GraphConnection objects and connect them to their source
// and target nodes.
double maxAbsWeight = 0.1; // Start at a non-zero value to prevent possibility of a divide by zero occuring.
IConnectionList connectionList = networkDef.ConnectionList;
int connCount = connectionList.Count;
for (int i = 0; i < connCount; i++)
{
// Create connection object and assign its source and target nodes.
INetworkConnection connection = connectionList[i];
GraphNode sourceNode = nodeDict[connection.SourceNodeId];
GraphNode targetNode = nodeDict[connection.TargetNodeId];
GraphConnection conn = new GraphConnection(sourceNode, targetNode, (float)connection.Weight);
// Add the connection to the connection lists on the source and target nodes.
sourceNode.OutConnectionList.Add(conn);
targetNode.InConnectionList.Add(conn);
// Track weight range oevr all connections.
double absWeight = Math.Abs(connection.Weight);
if (absWeight > maxAbsWeight)
{
maxAbsWeight = absWeight;
}
}
ioGraph.ConnectionWeightRange = (float)maxAbsWeight;
return(ioGraph);
}
/// <summary>
/// Layout nodes based on their depth within the network.
///
/// Note 1.
/// Input nodes are defined as being at layer zero and we position them in their own layer at the
/// top of the layout area. Any other type of node (hidden or output) node not connected to is also
/// defined as being at layer zero, if such nodes exist then we place them into their own layout
/// layer to visually separate them from the input nodes.
///
/// Note 2.
/// Output nodes can be at a range of depths, but for clarity we position them all in their own layer
/// at the bottom of the layout area. A hidden node can have a depth greater than or equal to one or
/// more of the output nodes, to handle this case neatly we ensure that the output nodes are always
/// in a layer by themselves by creating an additional layer in the layout if necessary.
///
/// Note 3.
/// Hidden nodes are positioned into layers between the inputs and outputs based on their depth.
///
/// Note 4.
/// Empty layers are not possible in the underlying network because for there to be a layer N node it
/// must have a connection from a layer N-1 node. However, in cyclic networks the output nodes can be
/// source nodes, but we also always paint output nodes in their own layout layer at the bottom of the
/// layout area. Therefore if the only node at a given depth is an output node then the layout layer
/// can be empty. To handle this neatly we check for empty layout layers before invoking the layout logic.
/// </summary>
/// <param name="graph">The network/graph structure to be laid out.</param>
/// <param name="layoutArea">The area the structure is to be laid out on.</param>
public void Layout(IOGraph graph, Size layoutArea)
{
int inputCount = graph.InputNodeList.Count;
int outputCount = graph.OutputNodeList.Count;
int hiddenCount = graph.HiddenNodeList.Count;
//=== Stratify all nodes into layout layers, each layer keyed by depth value.
SortedDictionary <int, List <GraphNode> > layersByDepth = new SortedDictionary <int, List <GraphNode> >();
// Special case. Key all input nodes by depth -1. This places them as the first layer and distinct
// from all other nodes.
layersByDepth.Add(-1, graph.InputNodeList);
// Stratify hidden nodes into layers.
// Count hidden nodes in each layer.
int[] hiddenNodeCountByLayerArr = new int[graph.Depth];
for (int i = 0; i < hiddenCount; i++)
{
hiddenNodeCountByLayerArr[graph.HiddenNodeList[i].Depth]++;
}
// Allocate storage per layer.
for (int i = 0; i < graph.Depth; i++)
{
int nodeCount = hiddenNodeCountByLayerArr[i];
if (0 != nodeCount)
{
layersByDepth.Add(i, new List <GraphNode>(nodeCount));
}
}
// Put hidden nodes into layer lists.
for (int i = 0; i < hiddenCount; i++)
{
GraphNode node = graph.HiddenNodeList[i];
layersByDepth[node.Depth].Add(node);
}
// Special case 2. Place output nodes in their own distinct layer at a depth one more than the max
// depth of the network. This places them as the last layer and distinct from all other nodes.
layersByDepth.Add(graph.Depth, graph.OutputNodeList);
//=== Layout.
// Calculate height of each layer. We divide the layout area height by the number of layers, but also
// define margins at the top and bottom of the view. To make best use of available height the margins
// are defined as a proportion of the layer height. Hence we have:
//
// ============================
// d - network depth.
// l - layer height.
// m - margin height (same height used for top and bottom margins).
// p - proportion of layer height that gives margin height.
// H - layout areas height
// ============================
//
// Derivation:
// ============================
// 1) l = (H-2m) / (d-1)
//
// 2) m = lp, therefore
//
// 3) l = (H-2pl) / (d-1), solve for l
//
// 4) l = H/(d-1) - 2pl/(d-1)
//
// 5) 1 = H/(d-1)l - 2p/(d-1)
//
// 6) H / (d-1)l = 1 + 2p/(d-1), inverting both sides gives
//
// 7) (d-1)l / H = 1/[ 1 + 2p/(d-1) ]
//
// 8) = (d-1) / ((d-1) + 2p)
//
// 9) = (d-1) / (d + 2p - 1), rearranging for l gives
//
// 10) l = H / (d + 2p - 1)
const float p = 0.9f;
const float p2 = 2f * p;
// Rounding will produce 'off by one' errors, e.g. all heights may not total height of layout area,
// but the effect is probably negligible on the quality of the layout.
int layoutLayerCount = layersByDepth.Count;
int l = (int)Math.Round((float)layoutArea.Height / ((float)layoutLayerCount + p2 - 1f));
int m = (int)Math.Round(l * p);
// Size struct to keep track of the area that bounds all nodes.
Size bounds = new Size(0, 0);
// Assign a position to each node, one layer at a time.
int yCurrent = m;
foreach (List <GraphNode> layerNodeList in layersByDepth.Values)
{
// Calculate inter-node gap and margin width (we use the same principle as with the vertical layout of layers, see notes above).
int nodeCount = layerNodeList.Count;
float xIncr = (float)layoutArea.Width / ((float)nodeCount + p2 - 1f);
int xMargin = (int)Math.Round(xIncr * p);
// Loop nodes in layer; Assign position to each.
float xCurrent = xMargin;
for (int nodeIdx = 0; nodeIdx < nodeCount; nodeIdx++, xCurrent += xIncr)
{
layerNodeList[nodeIdx].Position = new Point((int)xCurrent, yCurrent);
UpdateModelBounds(layerNodeList[nodeIdx], ref bounds);
}
// Increment y coord for next layer.
yCurrent += l;
}
// Store the bounds of the graph elements. Useful when drawing the graph.
graph.Bounds = bounds;
}
/// <summary>
/// Layout nodes evenly spaced out on a grid.
/// </summary>
/// <param name="graph">The network/graph structure to be layed out.</param>
/// <param name="layoutArea">The area the structrue is to be layed out on.</param>
public void Layout(IOGraph graph, Size layoutArea)
{
// Size struct to keep track of the area that bounds all nodes.
Size bounds = new Size(0,0);
// Some other useful variables.
int inputCount = graph.InputNodeList.Count;
int outputCount = graph.OutputNodeList.Count;
int hiddenCount = graph.HiddenNodeList.Count;
double heightWidthRatio = (double)layoutArea.Height/(double)layoutArea.Width;
// Determine how many layers/rows to arrange the nodes into.
// Note. we always show the inputs and outputs in their own rows, therefore this just
// handles how many additional rows are requried for the hidden nodes.
int numLayersHidden=0;
if(hiddenCount>0)
{ // Arrange nodes in a sqare and adjust for height/width ratio of layout area.
double sqrtHidden = Math.Sqrt(hiddenCount);
numLayersHidden = (int)Math.Floor(sqrtHidden * heightWidthRatio);
// Must be at least 1 layer if we have nodes.
numLayersHidden = Math.Max(1, numLayersHidden);
}
// Arrange the nodes.
int yMarginTop = (int)(layoutArea.Height * MarginProportionYTop);
int yMarginBottom = (int)(layoutArea.Height * MarginProportionYBottom);
int layoutHeight = layoutArea.Height - (yMarginTop + yMarginBottom);
int yCurrent = yMarginTop;
int yIncrement;
if(0 == numLayersHidden)
{ // Just two layers (input and output).
yIncrement = layoutHeight;
} else {
yIncrement = layoutHeight / (numLayersHidden+1);
}
// Input layer. Place all input nodes in one layer.
int layoutWidth = layoutArea.Width - (2 * MarginX);
int xIncrement = layoutWidth / (inputCount+1);
int xCurrent = MarginX + xIncrement;
// Loop input nodes.
for(int i=0; i<inputCount; i++)
{
GraphNode node = graph.InputNodeList[i];
node.Position = new Point(xCurrent, yCurrent);
UpdateModelBounds(node, ref bounds);
xCurrent += xIncrement;
}
// Increment yCurrent, ready for the next layer.
yCurrent += yIncrement;
// Layout hidden layers.
if(0 != numLayersHidden)
{
// Calculate the max number of nodes in any hidden layer.
int layerNodesMax = (int)Math.Ceiling((double)hiddenCount / (double)numLayersHidden);
// Keep track of how many nodes remain to be positioned. The last layer will have fewer
// than layerNodesMax if the number of nodes isn't a square number.
int nodesRemaining = hiddenCount;
int nodeIdx=0;
// Loop layers.
for(int i=0; i<numLayersHidden; i++)
{
// Calculate the number of nodes in this layer.
int layerNodeCount = Math.Min(nodesRemaining, layerNodesMax);
// Position nodes in this layer.
xIncrement = layoutWidth / (layerNodeCount+1);
xCurrent = MarginX + xIncrement;
// Loop nodes in this layer.
for(int j=0; j<layerNodeCount; j++, nodeIdx++)
{
GraphNode node = graph.HiddenNodeList[nodeIdx];
node.Position = new Point(xCurrent, yCurrent);
UpdateModelBounds(node, ref bounds);
xCurrent += xIncrement;
}
// Increment yCurrent, ready for the next layer.
yCurrent += yIncrement;
nodesRemaining -= layerNodeCount;
}
}
// Output layer. Place all output nodes in one layer.
xIncrement = layoutWidth / (outputCount+1);
xCurrent = MarginX + xIncrement;
// Loop output nodes.
for(int i=0; i<outputCount; i++)
{
GraphNode node = graph.OutputNodeList[i];
node.Position = new Point(xCurrent, yCurrent);
UpdateModelBounds(node, ref bounds);
xCurrent += xIncrement;
}
// Store the bounds of the graph elements. Useful when drawing the graph.
graph.Bounds = bounds;
}
/// <summary>
/// Create an IOGraph that represents the structure described by the provided INetworkDefinition.
/// </summary>
public IOGraph CreateGraph(INetworkDefinition networkDef)
{
// Perform depth analysis of network.
NetworkDepthInfo depthInfo;
if(networkDef.IsAcyclic)
{
AcyclicNetworkDepthAnalysis depthAnalysis = new AcyclicNetworkDepthAnalysis();
depthInfo = depthAnalysis.CalculateNodeDepths(networkDef);
}
else
{
CyclicNetworkDepthAnalysis depthAnalysis = new CyclicNetworkDepthAnalysis();
depthInfo = depthAnalysis.CalculateNodeDepths(networkDef);
}
// Create an IOGraph, allocating storage for the node lists.
INodeList nodeList = networkDef.NodeList;
int nodeCount = nodeList.Count;
int inputCount = networkDef.InputNodeCount + 1; // + to count bias as an input layer node.
int outputCount = networkDef.OutputNodeCount;
int hiddenCount = nodeCount - (inputCount + outputCount);
IOGraph ioGraph = new IOGraph(inputCount, outputCount, hiddenCount, 0f, depthInfo._networkDepth);
// We also build a dictionary of nodes keyed by innovation ID. This is used later
// to assign connections to nodes.
Dictionary<uint, GraphNode> nodeDict = new Dictionary<uint,GraphNode>(nodeCount);
// Loop input nodes.
int idx = 0;
for(int i=0; i<inputCount; i++, idx++)
{ // Create node, assign it a tag and add it to the node dictionary and the
// input node list of the IOGraph.
uint innovationId = nodeList[idx].Id;
GraphNode node = new GraphNode(innovationId.ToString());
node.AuxData = CreateGraphNodeAuxData(nodeList[idx]);
node.Depth = depthInfo._nodeDepthArr[idx];
nodeDict.Add(innovationId, node);
ioGraph.InputNodeList.Add(node);
}
// Loop output nodes.
for(int i=0; i<outputCount; i++, idx++)
{ // Create node, assign it a tag and add it to the node dictionary and the
// output node list of the IOGraph.
uint innovationId = nodeList[idx].Id;
GraphNode node = new GraphNode(innovationId.ToString());
node.AuxData = CreateGraphNodeAuxData(nodeList[idx]);
node.Depth = depthInfo._nodeDepthArr[idx];
nodeDict.Add(innovationId, node);
ioGraph.OutputNodeList.Add(node);
}
// Loop hidden nodes.
for(; idx<nodeCount; idx++)
{ // Create node, assign it a tag and add it to the node dictionary and the
// hidden node list of the IOGraph.
uint innovationId = nodeList[idx].Id;
GraphNode node = new GraphNode(innovationId.ToString());
node.AuxData = CreateGraphNodeAuxData(nodeList[idx]);
node.Depth = depthInfo._nodeDepthArr[idx];
nodeDict.Add(innovationId, node);
ioGraph.HiddenNodeList.Add(node);
}
// Loop connections. Build GraphConnection objects and connect them to their source
// and target nodes.
double maxAbsWeight = 0.1; // Start at a non-zero value to prevent possibility of a divide by zero occurring.
IConnectionList connectionList = networkDef.ConnectionList;
int connCount = connectionList.Count;
for(int i=0; i<connCount; i++)
{
// Create connection object and assign its source and target nodes.
INetworkConnection connection = connectionList[i];
GraphNode sourceNode = nodeDict[connection.SourceNodeId];
GraphNode targetNode = nodeDict[connection.TargetNodeId];
GraphConnection conn = new GraphConnection(sourceNode, targetNode, (float)connection.Weight);
// Add the connection to the connection lists on the source and target nodes.
sourceNode.OutConnectionList.Add(conn);
targetNode.InConnectionList.Add(conn);
// Track weight range over all connections.
double absWeight = Math.Abs(connection.Weight);
if(absWeight > maxAbsWeight) {
maxAbsWeight = absWeight;
}
}
ioGraph.ConnectionWeightRange = (float)maxAbsWeight;
return ioGraph;
}
/// <summary>
/// Layout nodes evenly spaced out on a grid.
/// </summary>
/// <param name="graph">The network/graph structure to be layed out.</param>
/// <param name="layoutArea">The area the structrue is to be layed out on.</param>
public void Layout(IOGraph graph, Size layoutArea)
{
// Size struct to keep track of the area that bounds all nodes.
Size bounds = new Size(0, 0);
// Some other useful variables.
int inputCount = graph.InputNodeList.Count;
int outputCount = graph.OutputNodeList.Count;
int hiddenCount = graph.HiddenNodeList.Count;
double heightWidthRatio = (double)layoutArea.Height / (double)layoutArea.Width;
// Determine how many layers/rows to arrange the nodes into.
// Note. we always show the inputs and outputs in their own rows, therefore this just
// handles how many additional rows are requried for the hidden nodes.
int numLayersHidden = 0;
if (hiddenCount > 0)
{ // Arrange nodes in a sqare and adjust for height/width ratio of layout area.
double sqrtHidden = Math.Sqrt(hiddenCount);
numLayersHidden = (int)Math.Floor(sqrtHidden * heightWidthRatio);
// Must be at least 1 layer if we have nodes.
numLayersHidden = Math.Max(1, numLayersHidden);
}
// Arrange the nodes.
int yMarginTop = (int)(layoutArea.Height * MarginProportionYTop);
int yMarginBottom = (int)(layoutArea.Height * MarginProportionYBottom);
int layoutHeight = layoutArea.Height - (yMarginTop + yMarginBottom);
int yCurrent = yMarginTop;
int yIncrement;
if (0 == numLayersHidden)
{ // Just two layers (input and output).
yIncrement = layoutHeight;
}
else
{
yIncrement = layoutHeight / (numLayersHidden + 1);
}
// Input layer. Place all input nodes in one layer.
int layoutWidth = layoutArea.Width - (2 * MarginX);
int xIncrement = layoutWidth / (inputCount + 1);
int xCurrent = MarginX + xIncrement;
// Loop input nodes.
for (int i = 0; i < inputCount; i++)
{
GraphNode node = graph.InputNodeList[i];
node.Position = new Point(xCurrent, yCurrent);
UpdateModelBounds(node, ref bounds);
xCurrent += xIncrement;
}
// Increment yCurrent, ready for the next layer.
yCurrent += yIncrement;
// Layout hidden layers.
if (0 != numLayersHidden)
{
// Calculate the max number of nodes in any hidden layer.
int layerNodesMax = (int)Math.Ceiling((double)hiddenCount / (double)numLayersHidden);
// Keep track of how many nodes remain to be positioned. The last layer will have fewer
// than layerNodesMax if the number of nodes isn't a square number.
int nodesRemaining = hiddenCount;
int nodeIdx = 0;
// Loop layers.
for (int i = 0; i < numLayersHidden; i++)
{
// Calculate the number of nodes in this layer.
int layerNodeCount = Math.Min(nodesRemaining, layerNodesMax);
// Position nodes in this layer.
xIncrement = layoutWidth / (layerNodeCount + 1);
xCurrent = MarginX + xIncrement;
// Loop nodes in this layer.
for (int j = 0; j < layerNodeCount; j++, nodeIdx++)
{
GraphNode node = graph.HiddenNodeList[nodeIdx];
node.Position = new Point(xCurrent, yCurrent);
UpdateModelBounds(node, ref bounds);
xCurrent += xIncrement;
}
// Increment yCurrent, ready for the next layer.
yCurrent += yIncrement;
nodesRemaining -= layerNodeCount;
}
}
// Output layer. Place all output nodes in one layer.
xIncrement = layoutWidth / (outputCount + 1);
xCurrent = MarginX + xIncrement;
// Loop output nodes.
for (int i = 0; i < outputCount; i++)
{
GraphNode node = graph.OutputNodeList[i];
node.Position = new Point(xCurrent, yCurrent);
UpdateModelBounds(node, ref bounds);
xCurrent += xIncrement;
}
// Store the bounds of the graph elements. Useful when drawing the graph.
graph.Bounds = bounds;
}