public IWeightMatrix Step(IWeightMatrix input, IComputeGraph innerGraph)
{
var hidden_prev = ht;
var cell_prev = ct;
var inputs = innerGraph.ConcatColumns(input, hidden_prev);
var bs = innerGraph.RepeatRows(b, input.Rows);
var hhSum = innerGraph.MulAdd(inputs, Wxh, bs);
(var gates_raw, var cell_write_raw) = innerGraph.SplitColumns(hhSum, hdim * 3, hdim);
var gates = innerGraph.Sigmoid(gates_raw);
var cell_write = innerGraph.Tanh(cell_write_raw);
(var input_gate, var forget_gate, var output_gate) = innerGraph.SplitColumns(gates, hdim, hdim, hdim);
// compute new cell activation
var retain_cell = innerGraph.EltMul(forget_gate, cell_prev); // what do we keep from cell
var write_cell = innerGraph.EltMul(input_gate, cell_write); // what do we write to cell
ct = innerGraph.Add(retain_cell, write_cell); // new cell contents
// compute hidden state as gated, saturated cell activations
ht = innerGraph.EltMul(output_gate, innerGraph.Tanh(ct));
return(ht);
}
public IWeightMatrix Perform(IWeightMatrix state, AttentionPreProcessResult attenPreProcessResult, IComputeGraph g)
{
var bWas = g.RepeatRows(bWa, state.Rows);
var wc = g.MulAdd(state, Wa, bWas);
var wcs = g.RepeatRows(wc, attenPreProcessResult.inputsUnfolder[0].Rows);
var ggs = g.AddTanh(attenPreProcessResult.uhs, wcs);
var atten = g.Mul(ggs, V);
List <IWeightMatrix> attens = g.UnFolderRow(atten, m_batchSize);
List <IWeightMatrix> contexts = new List <IWeightMatrix>();
List <IWeightMatrix> attensT = new List <IWeightMatrix>();
for (int i = 0; i < m_batchSize; i++)
{
attensT.Add(g.Transpose2(attens[i]));
}
var attenT = g.ConcatRows(attensT);
var attenSoftmax = g.SoftmaxM(attenT);
for (int i = 0; i < m_batchSize; i++)
{
IWeightMatrix context = g.Mul(g.PeekRow(attenSoftmax, i), attenPreProcessResult.inputsUnfolder[i]);
contexts.Add(context);
}
return(g.ConcatRows(contexts));
}
public IWeightMatrix Step(IWeightMatrix input, IComputeGraph innerGraph)
{
var hidden_prev = ht;
var cell_prev = ct;
var inputs = innerGraph.ConcatColumns(input, hidden_prev);
var bs = innerGraph.RepeatRows(b, input.Rows);
var hhSum = innerGraph.MulAdd(inputs, Wxh, bs);
var hhSum2 = layerNorm1.Process(hhSum, innerGraph);
(var gates_raw, var cell_write_raw) = innerGraph.SplitColumns(hhSum2, hdim * 3, hdim);
var gates = innerGraph.Sigmoid(gates_raw);
var cell_write = innerGraph.Tanh(cell_write_raw);
(var input_gate, var forget_gate, var output_gate) = innerGraph.SplitColumns(gates, hdim, hdim, hdim);
// compute new cell activation: ct = forget_gate * cell_prev + input_gate * cell_write
ct = innerGraph.EltMulMulAdd(forget_gate, cell_prev, input_gate, cell_write);
var ct2 = layerNorm2.Process(ct, innerGraph);
// compute hidden state as gated, saturated cell activations
ht = innerGraph.EltMul(output_gate, innerGraph.Tanh(ct2));
return(ht);
}
/// <summary>
/// Update LSTM-Attention cells according to given weights
/// </summary>
/// <param name="context">The context weights for attention</param>
/// <param name="input">The input weights</param>
/// <param name="computeGraph">The compute graph to build workflow</param>
/// <returns>Update hidden weights</returns>
public IWeightMatrix Step(IWeightMatrix context, IWeightMatrix input, IComputeGraph computeGraph)
{
var cell_prev = ct;
var hidden_prev = ht;
var hxhc = computeGraph.ConcatColumns(input, hidden_prev, context);
var bs = computeGraph.RepeatRows(b, input.Rows);
var hhSum = computeGraph.MulAdd(hxhc, Wxhc, bs);
(var gates_raw, var cell_write_raw) = computeGraph.SplitColumns(hhSum, hdim * 3, hdim);
var gates = computeGraph.Sigmoid(gates_raw);
var cell_write = computeGraph.Tanh(cell_write_raw);
(var input_gate, var forget_gate, var output_gate) = computeGraph.SplitColumns(gates, hdim, hdim, hdim);
// compute new cell activation
//var retain_cell = computeGraph.EltMul(forget_gate, cell_prev);
//var write_cell = computeGraph.EltMul(input_gate, cell_write);
//ct = computeGraph.Add(retain_cell, write_cell);
ct = computeGraph.EltMulMulAdd(forget_gate, cell_prev, input_gate, cell_write);
ht = computeGraph.EltMul(output_gate, computeGraph.Tanh(ct));
return(ht);
}
public AttentionPreProcessResult PreProcess(IWeightMatrix inputs, IComputeGraph g)
{
AttentionPreProcessResult r = new AttentionPreProcessResult();
IWeightMatrix bUas = g.RepeatRows(bUa, inputs.Rows);
r.uhs = g.MulAdd(inputs, Ua, bUas);
r.inputs = g.ConcatRows(g.UnFolderRow(inputs, m_batchSize));
return(r);
}
public IWeightMatrix Perform(IWeightMatrix state, AttentionPreProcessResult attenPreProcessResult, IComputeGraph g)
{
var bWas = g.RepeatRows(bWa, state.Rows);
var wc = g.MulAdd(state, Wa, bWas);
var wcs = g.RepeatRows(wc, attenPreProcessResult.inputs.Rows / m_batchSize);
var ggs = g.AddTanh(attenPreProcessResult.uhs, wcs);
var atten = g.Mul(ggs, V);
var atten2 = g.PermuteBatch(atten, m_batchSize);
var attenT = g.Transpose2(atten2);
var attenT2 = g.View(attenT, m_batchSize, attenPreProcessResult.inputs.Rows / m_batchSize);
var attenSoftmax = g.Softmax(attenT2);
IWeightMatrix contexts = g.MulBatch(attenSoftmax, attenPreProcessResult.inputs, m_batchSize);
return(contexts);
}
/// <summary>
/// Update LSTM-Attention cells according to given weights
/// </summary>
/// <param name="context">The context weights for attention</param>
/// <param name="input">The input weights</param>
/// <param name="computeGraph">The compute graph to build workflow</param>
/// <returns>Update hidden weights</returns>
public IWeightMatrix Step(IWeightMatrix context, IWeightMatrix input, IComputeGraph computeGraph)
{
var cell_prev = ct;
var hidden_prev = ht;
var hxhc = computeGraph.ConcatColumns(input, hidden_prev, context);
var bs = computeGraph.RepeatRows(b, input.Rows);
var hhSum = computeGraph.MulAdd(hxhc, Wxhc, bs);
var hhSum2 = layerNorm1.Process(hhSum, computeGraph);
(var gates_raw, var cell_write_raw) = computeGraph.SplitColumns(hhSum2, hdim * 3, hdim);
var gates = computeGraph.Sigmoid(gates_raw);
var cell_write = computeGraph.Tanh(cell_write_raw);
(var input_gate, var forget_gate, var output_gate) = computeGraph.SplitColumns(gates, hdim, hdim, hdim);
// compute new cell activation: ct = forget_gate * cell_prev + input_gate * cell_write
ct = computeGraph.EltMulMulAdd(forget_gate, cell_prev, input_gate, cell_write);
var ct2 = layerNorm2.Process(ct, computeGraph);
ht = computeGraph.EltMul(output_gate, computeGraph.Tanh(ct2));
return(ht);
}
public IWeightMatrix Process(IWeightMatrix inputT, IComputeGraph g)
{
var bds = g.RepeatRows(m_Bd, inputT.Rows);
return(g.MulAdd(inputT, m_Whd, bds));
}
/// <summary>
/// Decode output sentences in training
/// </summary>
/// <param name="outputSentences"></param>
/// <param name="g"></param>
/// <param name="encodedOutputs"></param>
/// <param name="decoder"></param>
/// <param name="Whd"></param>
/// <param name="bd"></param>
/// <param name="Embedding"></param>
/// <param name="predictSentence"></param>
/// <returns></returns>
private float Decode(List <List <string> > outputSentences, IComputeGraph g, IWeightMatrix encodedOutputs, AttentionDecoder decoder,
IWeightMatrix Whd, IWeightMatrix bd, IWeightMatrix Embedding, out List <List <string> > predictSentence)
{
predictSentence = null;
float cost = 0.0f;
var attPreProcessResult = decoder.PreProcess(encodedOutputs, g);
var originalOutputLengths = PadSentences(outputSentences);
int seqLen = outputSentences[0].Count;
int[] ix_inputs = new int[m_batchSize];
int[] ix_targets = new int[m_batchSize];
for (int i = 0; i < ix_inputs.Length; i++)
{
ix_inputs[i] = (int)SENTTAGS.START;
}
var bds = g.RepeatRows(bd, m_batchSize);
for (int i = 0; i < seqLen + 1; i++)
{
//Get embedding for all sentence in the batch at position i
List <IWeightMatrix> inputs = new List <IWeightMatrix>();
for (int j = 0; j < m_batchSize; j++)
{
List <string> OutputSentence = outputSentences[j];
ix_targets[j] = (int)SENTTAGS.UNK;
if (i >= seqLen)
{
ix_targets[j] = (int)SENTTAGS.END;
}
else
{
if (m_tgtWordToIndex.ContainsKey(OutputSentence[i]))
{
ix_targets[j] = m_tgtWordToIndex[OutputSentence[i]];
}
}
var x = g.PeekRow(Embedding, ix_inputs[j]);
inputs.Add(x);
}
var inputsM = g.ConcatRows(inputs);
//Decode output sentence at position i
var eOutput = decoder.Decode(inputsM, attPreProcessResult, g);
if (m_dropoutRatio > 0.0f)
{
eOutput = g.Dropout(eOutput, m_dropoutRatio);
}
//Softmax for output
var o = g.MulAdd(eOutput, Whd, bds);
var probs = g.Softmax(o, false);
o.ReleaseWeight();
//Calculate loss for each word in the batch
List <IWeightMatrix> probs_g = g.UnFolderRow(probs, m_batchSize, false);
for (int k = 0; k < m_batchSize; k++)
{
var probs_k = probs_g[k];
var score_k = probs_k.GetWeightAt(ix_targets[k]);
if (i < originalOutputLengths[k] + 1)
{
cost += (float)-Math.Log(score_k);
}
probs_k.SetWeightAt(score_k - 1, ix_targets[k]);
ix_inputs[k] = ix_targets[k];
probs_k.Dispose();
}
o.SetGradientByWeight(probs);
}
return(cost);
}