/// <summary>
/// Construct with a single IActivationFunction.
/// </summary>
/// <param name="activationFn"></param>
public NeatActivationFunctionLibrary(IActivationFunction activationFn)
{
_activationFn = activationFn;
_activationFnInfo = new ActivationFunctionInfo(0, 1.0, activationFn);
_activationFnInfoList = new List<ActivationFunctionInfo>(1);
_activationFnInfoList.Add(_activationFnInfo);
}
/// <summary>
/// Normalize the selection probabilities of the provided ActivationFunctionInfo items.
/// </summary>
private static void NormalizeSelectionProbabilities(IList <ActivationFunctionInfo> fnList)
{
double total = 0.0;
int count = fnList.Count;
for (int i = 0; i < count; i++)
{
total += fnList[i].SelectionProbability;
}
if (Math.Abs(total - 1.0) < 0.0001)
{ // Probabilities already normalized to within acceptable limits (from rounding errors).
return;
}
// Normalize the probabilities. Note that ActivationFunctionInfo is immutable therefore
// we replace the existing items.
for (int i = 0; i < count; i++)
{
ActivationFunctionInfo item = fnList[i];
fnList[i] = new ActivationFunctionInfo(item.Id, item.SelectionProbability / total, item.ActivationFunction);
}
}
/// <summary>
/// Reads an IActivationFunctionLibrary from the provided XmlReader.
/// </summary>
public static IActivationFunctionLibrary ReadActivationFunctionLibrary(XmlReader xr)
{
XmlIoUtils.MoveToElement(xr, false, __ElemActivationFunctions);
// Create a reader over the sub-tree.
List <ActivationFunctionInfo> fnList = new List <ActivationFunctionInfo>();
using (XmlReader xrSubtree = xr.ReadSubtree())
{
// Re-scan for the root element.
XmlIoUtils.MoveToElement(xrSubtree, false);
// Move to first function elem.
XmlIoUtils.MoveToElement(xrSubtree, true, __ElemActivationFn);
// Read function elements.
do
{
int id = XmlIoUtils.ReadAttributeAsInt(xrSubtree, __AttrId);
double selectionProb = XmlIoUtils.ReadAttributeAsDouble(xrSubtree, __AttrProbability);
string fnName = xrSubtree.GetAttribute(__AttrName);
// Lookup function name.
IActivationFunction activationFn = GetActivationFunction(fnName);
// Add new function to our list of functions.
ActivationFunctionInfo fnInfo = new ActivationFunctionInfo(id, selectionProb, activationFn);
fnList.Add(fnInfo);
}while(xrSubtree.ReadToNextSibling(__ElemActivationFn));
}
// If we have read library items then ensure that their selection probabilities are normalized.
if (fnList.Count != 0)
{
NormalizeSelectionProbabilities(fnList);
}
return(new DefaultActivationFunctionLibrary(fnList));
}
/// <summary>
/// Normalize the selection probabilities of the provided ActivationFunctionInfo items.
/// </summary>
private static void NormalizeSelectionProbabilities(IList<ActivationFunctionInfo> fnList)
{
double total = 0.0;
int count = fnList.Count;
for(int i=0; i<count; i++) {
total += fnList[i].SelectionProbability;
}
if(Math.Abs(total - 1.0) < 0.0001)
{ // Probabilities already normalized to within acceptable limits (from rounding errors).
return;
}
// Normalize the probabilities. Note that ActivationFunctionInfo is immutable therefore
// we replace the existing items.
for(int i=0; i<count; i++)
{
ActivationFunctionInfo item = fnList[i];
fnList[i] = new ActivationFunctionInfo(item.Id, item.SelectionProbability/total, item.ActivationFunction);
}
}
/// <summary>
/// Reads an IActivationFunctionLibrary from the provided XmlReader.
/// </summary>
public static IActivationFunctionLibrary ReadActivationFunctionLibrary(XmlReader xr)
{
XmlIoUtils.MoveToElement(xr, false, __ElemActivationFunctions);
// Create a reader over the sub-tree.
List<ActivationFunctionInfo> fnList = new List<ActivationFunctionInfo>();
using(XmlReader xrSubtree = xr.ReadSubtree())
{
// Re-scan for the root element.
XmlIoUtils.MoveToElement(xrSubtree, false);
// Move to first function elem.
XmlIoUtils.MoveToElement(xrSubtree, true, __ElemActivationFn);
// Read function elements.
do
{
int id = XmlIoUtils.ReadAttributeAsInt(xrSubtree, __AttrId);
double selectionProb = XmlIoUtils.ReadAttributeAsDouble(xrSubtree, __AttrProbability);
string fnName = xrSubtree.GetAttribute(__AttrName);
// Lookup function name.
IActivationFunction activationFn = GetActivationFunction(fnName);
// Add new function to our list of functions.
ActivationFunctionInfo fnInfo = new ActivationFunctionInfo(id, selectionProb, activationFn);
fnList.Add(fnInfo);
}
while(xrSubtree.ReadToNextSibling(__ElemActivationFn));
}
// If we have read library items then ensure that their selection probabilities are normalized.
if(fnList.Count != 0) {
NormalizeSelectionProbabilities(fnList);
}
return new DefaultActivationFunctionLibrary(fnList);
}