public override float Forward(
int[] targets,
int targetIndex,
Model.State state,
float lr,
bool backprop)
{
Debug.Assert(targetIndex >= 0);
Debug.Assert(targetIndex < targets.Length);
ComputeOutput(state);
var target = targets[targetIndex];
if (backprop)
{
var osz = wo_.Size(0);
for (int i = 0; i < osz; i++)
{
var label = (i == target) ? 1f : 0f;
var alpha = lr * (label - state.output[i]);
state.grad.AddRow(wo_, i, alpha);
wo_.AddVectorToRow(state.hidden.Data, i, alpha);
}
}
return(-Log(state.output[target]));
}
public float BinaryLogistic(
int target,
Model.State state,
bool labelIsPositive,
float lr,
bool backprop)
{
var score = Sigmoid(wo_.DotRow(state.hidden.Data, target));
if (backprop)
{
var flabelIsPositive = (float)Convert.ToDouble(labelIsPositive);
var alpha = lr * (flabelIsPositive - score);
state.grad.AddRow(wo_, target, alpha);
wo_.AddVectorToRow(state.hidden.Data, target, alpha);
}
if (labelIsPositive)
{
return(-Log(score));
}
else
{
return(-Log(1f - score));
}
}
public override void ComputeOutput(Model.State state)
{
Vector output = state.output;
output.Mul(wo_, state.hidden);
var max = output[0];
var z = 0f;
var osz = output.Size();
for (int i = 0; i < osz; i++)
{
max = Math.Max(output[i], max);
}
for (int i = 0; i < osz; i++)
{
output[i] = (float)Math.Exp(output[i] - max);
z += output[i];
}
for (int i = 0; i < osz; i++)
{
output[i] /= z;
}
}
public override void Predict(
int k,
float threshold,
Predictions heap,
Model.State state)
{
DFS(k, threshold, 2 * osz_ - 2, 0f, heap, state.hidden.Data);
}
public virtual void Predict(
int k,
float threshold,
Predictions heap,
Model.State state)
{
ComputeOutput(state);
FindKBest(k, threshold, heap, state.output.Data);
}
protected void TrainThread(int threadId)
{
var ifs = new FileStream(args_.input, FileMode.Open, FileAccess.Read);
ifs.Flush();
ifs.Seek(threadId * ifs.Length / args_.thread, SeekOrigin.Begin);
var state = new Model.State(args_.dim, (int)output_.Size(0), threadId);
var ntokens = dict_.ntokens;
var localTokenCount = 0L;
var line = new List <int>();
var labels = new List <int>();
while (tokenCount_ < args_.epoch * ntokens)
{
var progress = (float)tokenCount_ / (args_.epoch * ntokens);
var lr = (float)args_.lr * (1f - progress);
if (args_.model == ModelName.sup)
{
localTokenCount += dict_.GetLine(ifs, line, labels);
Supervised(state, lr, line.ToArray(), labels.ToArray());
}
else if (args_.model == ModelName.cbow)
{
localTokenCount += dict_.GetLine(ifs, line, state.rng);
Cbow(state, lr, line.ToArray());
}
else if (args_.model == ModelName.sg)
{
localTokenCount += dict_.GetLine(ifs, line, state.rng);
Skipgram(state, lr, line.ToArray());
}
if (localTokenCount > args_.lrUpdateRate)
{
tokenCount_ += localTokenCount;
localTokenCount = 0;
if (threadId == 0 && args_.verbose > 1)
{
loss_ = state.GetLoss();
}
}
}
if (threadId == 0)
{
loss_ = state.GetLoss();
}
ifs.Close();
}
public override void ComputeOutput(Model.State state)
{
Vector output = state.output;
output.Mul(wo_, state.hidden);
var osz = output.Size();
for (int i = 0; i < osz; i++)
{
output[i] = Sigmoid(output[i]);
}
}
protected void Skipgram(Model.State state, float lr, int[] line)
{
for (int w = 0; w < line.Length; w++)
{
var boundary = state.rng.Next(1, args_.ws);
var ngrams = dict_.GetSubwords(line[w]);
for (int c = -boundary; c <= boundary; c++)
{
if (c != 0 && w + c >= 0 && w + c < line.Length)
{
model_.Update(ngrams, line, w + c, lr, state);
}
}
}
}
public void Predict(int k, int[] words, Predictions predictions, float threshold = 0f)
{
if (words.Length == 0)
{
return;
}
var state = new Model.State(args_.dim, dict_.nlabels, 0);
if (args_.model != ModelName.sup)
{
throw new ArgumentException("Model needs to be supervised for prediction!");
}
model_.Predict(words, k, threshold, predictions, state);
}
public override float Forward(
int[] targets,
int targetIndex,
Model.State state,
float lr,
bool backprop)
{
var loss = 0f;
var osz = state.output.Size();
for (int i = 0; i < osz; i++)
{
bool isMatch = Utils.Contains(targets, i);
loss += BinaryLogistic(i, state, isMatch, lr, backprop);
}
return(loss);
}
public override float Forward(
int[] targets,
int targetIndex,
Model.State state,
float lr,
bool backprop)
{
var loss = 0f;
var target = targets[targetIndex];
var binaryCode = codes_[target];
var pathToRoot = paths_[target];
for (int i = 0; i < pathToRoot.Length; i++)
{
loss += BinaryLogistic(pathToRoot[i], state, binaryCode[i], lr, backprop);
}
return(loss);
}
public override float Forward(
int[] targets,
int targetIndex,
Model.State state,
float lr,
bool backprop)
{
Debug.Assert(targetIndex >= 0);
Debug.Assert(targetIndex < targets.Length);
var target = targets[targetIndex];
var loss = BinaryLogistic(target, state, true, lr, backprop);
for (int n = 0; n < neg_; n++)
{
var negativeTarget = getNegative(target, state.rng);
loss += BinaryLogistic(negativeTarget, state, false, lr, backprop);
}
return(loss);
}
protected void Cbow(Model.State state, float lr, int[] line)
{
var bow = new List <int>();
for (int w = 0; w < line.Length; w++)
{
var boundary = state.rng.Next(1, args_.ws);
bow.Clear();
for (int c = -boundary; c <= boundary; c++)
{
if (c != 0 && w + c >= 0 && w + c < line.Length)
{
var ngrams = dict_.GetSubwords(line[w + c]);
bow.AddRange(ngrams);
}
}
model_.Update(bow.ToArray(), line, w, lr, state);
}
}
protected void Supervised(
Model.State state,
float lr,
int[] line,
int[] labels)
{
if (labels.Length == 0 || line.Length == 0)
{
return;
}
if (args_.loss == LossName.ova)
{
model_.Update(line, labels, Model.kAllLabelsAsTarget, lr, state);
}
else
{
var i = state.rng.Next(0, labels.Length - 1);
model_.Update(line, labels, i, lr, state);
}
}
public abstract void ComputeOutput(Model.State state);
public abstract float Forward(
int[] targets,
int targetIndex,
Model.State state,
float lr,
bool backprop);
