/// <summary>
/// Scaled multi-heads attention component with skip connectioned feed forward layers
/// </summary>
/// <param name="inputQ">The input Q tensor</param>
/// <param name="keyMask">The mask for softmax</param>
/// <param name="batchSize">Batch size of input data set</param>
/// <param name="graph">The instance of computing graph</param>
/// <returns>Transformered output tensor</returns>
public (IWeightTensor, IWeightTensor) Perform(IWeightTensor inputQ, IWeightTensor keyMask, int batchSize, IComputeGraph graph, bool outputAttenWeights = false)
{
using IComputeGraph g = graph.CreateSubGraph($"{m_name}_MultiHeadAttention");
int seqLenQ = inputQ.Rows / batchSize;
IWeightTensor inputQNorm = layerNormQ.Norm(inputQ, g);
//Input projections
var weightedQKV = g.View(g.Affine(inputQNorm, QKV, QKVb), dims: new long[] { batchSize, seqLenQ, 3, m_multiHeadNum, m_d });
var allQ = g.Select(weightedQKV, 2, 0);
var allK = g.Select(weightedQKV, 2, 1);
var allV = g.Select(weightedQKV, 2, 2);
//Multi-head attentions
IWeightTensor Qs = g.View(g.AsContiguous(g.Transpose(allQ, 1, 2)), dims: new long[] { batchSize *m_multiHeadNum, seqLenQ, m_d });
IWeightTensor Ks = g.View(g.AsContiguous(g.Transpose(g.Transpose(allK, 1, 2), 2, 3)), dims: new long[] { batchSize *m_multiHeadNum, m_d, seqLenQ });
IWeightTensor Vs = g.View(g.AsContiguous(g.Transpose(allV, 1, 2)), dims: new long[] { batchSize *m_multiHeadNum, seqLenQ, m_d });
// Scaled softmax
float scale = 1.0f / (float)(Math.Sqrt(m_d));
var attn = g.MulBatch(Qs, Ks, scale);
attn = g.View(attn, dims: new long[] { batchSize, m_multiHeadNum, seqLenQ, seqLenQ });
if (keyMask != null)
{
attn = g.Add(attn, keyMask, inPlace: true);
}
var attnProbs = g.Softmax(attn, inPlace: true);
IWeightTensor sumAttnWeights = null;
if (outputAttenWeights)
{
//Merge all attention probs over multi-heads
sumAttnWeights = graph.Sum(attnProbs, 1);
sumAttnWeights = graph.Div(sumAttnWeights, (float)m_multiHeadNum);
sumAttnWeights = graph.View(sumAttnWeights, new long[] { batchSize *seqLenQ, seqLenQ });
}
attnProbs = g.View(attnProbs, dims: new long[] { batchSize *m_multiHeadNum, seqLenQ, seqLenQ });
IWeightTensor o = g.View(g.MulBatch(attnProbs, Vs), dims: new long[] { batchSize, m_multiHeadNum, seqLenQ, m_d });
IWeightTensor W = g.View(g.AsContiguous(g.Transpose(o, 1, 2)), dims: new long[] { batchSize *seqLenQ, m_multiHeadNum *m_d });
// Output projection
IWeightTensor finalAttResults = g.Dropout(g.Affine(W, W0, b0), batchSize, m_dropoutRatio, inPlace: true);
IWeightTensor result = graph.Add(finalAttResults, inputQ, inPlace: true);
return(result, sumAttnWeights);
}
public IWeightTensor Step(IWeightTensor input, IComputeGraph g)
{
using (IComputeGraph innerGraph = g.CreateSubGraph(m_name))
{
IWeightTensor hidden_prev = m_hidden;
IWeightTensor cell_prev = m_cell;
IWeightTensor inputs = innerGraph.Concate(1, input, hidden_prev);
IWeightTensor hhSum = innerGraph.Affine(inputs, m_Wxh, m_b);
IWeightTensor hhSum2 = m_layerNorm1.Norm(hhSum, innerGraph);
(IWeightTensor gates_raw, IWeightTensor cell_write_raw) = innerGraph.SplitColumns(hhSum2, m_hdim * 3, m_hdim);
IWeightTensor gates = innerGraph.Sigmoid(gates_raw);
IWeightTensor cell_write = innerGraph.Tanh(cell_write_raw);
(IWeightTensor input_gate, IWeightTensor forget_gate, IWeightTensor output_gate) = innerGraph.SplitColumns(gates, m_hdim, m_hdim, m_hdim);
// compute new cell activation: ct = forget_gate * cell_prev + input_gate * cell_write
m_cell = g.EltMulMulAdd(forget_gate, cell_prev, input_gate, cell_write);
IWeightTensor ct2 = m_layerNorm2.Norm(m_cell, innerGraph);
// compute hidden state as gated, saturated cell activations
m_hidden = g.EltMul(output_gate, innerGraph.Tanh(ct2));
return(m_hidden);
}
}
/// <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 IWeightTensor Step(IWeightTensor context, IWeightTensor input, IComputeGraph g)
{
using (IComputeGraph computeGraph = g.CreateSubGraph(m_name))
{
IWeightTensor cell_prev = Cell;
IWeightTensor hidden_prev = Hidden;
IWeightTensor hxhc = computeGraph.Concate(1, input, hidden_prev, context);
IWeightTensor hhSum = computeGraph.Affine(hxhc, m_Wxhc, m_b);
IWeightTensor hhSum2 = m_layerNorm1.Norm(hhSum, computeGraph);
(IWeightTensor gates_raw, IWeightTensor cell_write_raw) = computeGraph.SplitColumns(hhSum2, m_hiddenDim * 3, m_hiddenDim);
IWeightTensor gates = computeGraph.Sigmoid(gates_raw);
IWeightTensor cell_write = computeGraph.Tanh(cell_write_raw);
(IWeightTensor input_gate, IWeightTensor forget_gate, IWeightTensor output_gate) = computeGraph.SplitColumns(gates, m_hiddenDim, m_hiddenDim, m_hiddenDim);
// compute new cell activation: ct = forget_gate * cell_prev + input_gate * cell_write
Cell = g.EltMulMulAdd(forget_gate, cell_prev, input_gate, cell_write);
IWeightTensor ct2 = m_layerNorm2.Norm(Cell, computeGraph);
Hidden = g.EltMul(output_gate, computeGraph.Tanh(ct2));
return(Hidden);
}
}
/// <summary>
/// Transformer encoder
/// </summary>
/// <param name="rawInputs"></param>
/// <param name="g"></param>
/// <returns></returns>
public IWeightTensor Encode(IWeightTensor inputs, int batchSize, IComputeGraph g, IWeightTensor srcSelfMask)
{
using (IComputeGraph subg = g.CreateSubGraph($"{m_name}_Encoder"))
{
IWeightTensor maskTensor = null;
if (srcSelfMask != null)
{
int seqLen = inputs.Rows / batchSize;
using var keyMaskView = subg.View(srcSelfMask, dims: new long[] { batchSize, 1, seqLen, seqLen });
maskTensor = subg.Expand(keyMaskView, dims: new long[] { batchSize, m_multiHeadNum, seqLen, seqLen });
}
IWeightTensor attnProbs = null;
for (int k = 0; k < m_encoders.Count; k++)
{
(inputs, attnProbs) = m_encoders[k].Perform(inputs, maskTensor, batchSize, subg, outputAttenWeights: false);
inputs = m_posFFNs[k].Perform(inputs, batchSize, subg);
}
inputs = layerNorm.Norm(inputs, subg);
inputs.UnbindFromComputeGraph();
if (attnProbs != null)
{
attnProbs.UnbindFromComputeGraph();
}
if (maskTensor != null)
{
maskTensor.Dispose();
}
}
return(inputs);
}
/// <summary>
/// Transformer encoder
/// </summary>
/// <param name="rawInputs"></param>
/// <param name="g"></param>
/// <returns></returns>
///
public (IWeightTensor, IWeightTensor) Decode(IWeightTensor tgtInputs, IWeightTensor encOutputBatchFirst, IWeightTensor tgtSelfMask, IWeightTensor srcTgtMask, int batchSize, IComputeGraph g, bool outputAttnWeights = false, Dictionary <string, IWeightTensor> cachedTensors = null)
{
IWeightTensor attnProbs = null;
using (IComputeGraph subg = g.CreateSubGraph($"{m_name}_Decoder"))
{
int seqLenQ = tgtInputs.Rows / batchSize;
// SeqLenK must be euqal to SeqLenV
int seqLenK = encOutputBatchFirst.Rows / batchSize;
IWeightTensor selfMaskTensor = null;
if (tgtSelfMask != null)
{
selfMaskTensor = subg.Expand(tgtSelfMask, dims: new long[] { batchSize, m_multiHeadNum, seqLenQ, seqLenQ });
}
IWeightTensor crossMaskTensor = null;
if (srcTgtMask != null)
{
crossMaskTensor = subg.Expand(srcTgtMask, dims: new long[] { batchSize, m_multiHeadNum, seqLenQ, seqLenK });
}
for (int k = 0; k < m_selfAttns.Count; k++)
{
(tgtInputs, attnProbs) = m_selfAttns[k].Perform(tgtInputs, selfMaskTensor, batchSize, subg, outputAttenWeights: false);
(tgtInputs, attnProbs) = m_encAttns[k].Perform(tgtInputs, encOutputBatchFirst, encOutputBatchFirst, crossMaskTensor, batchSize, subg, outputAttenWeights: (outputAttnWeights && k == m_selfAttns.Count - 1), cachedTensors: cachedTensors);
tgtInputs = m_posFFNs[k].Perform(tgtInputs, batchSize, subg);
}
tgtInputs = layerNorm.Norm(tgtInputs, subg);
tgtInputs.UnbindFromComputeGraph();
if (attnProbs != null)
{
attnProbs.UnbindFromComputeGraph();
}
if (selfMaskTensor != null)
{
selfMaskTensor.Dispose();
}
if (crossMaskTensor != null)
{
crossMaskTensor.Dispose();
}
}
// tgtInputs = m_decoderFFLayer.Process(tgtInputs, batchSize, g);
return(tgtInputs, attnProbs);
}
/// <summary>
/// Scaled multi-heads attention component with skip connectioned feed forward layers
/// </summary>
/// <param name="inputQ">The input Q tensor</param>
/// <param name="inputK">The input K tensor</param>
/// <param name="inputV">The input V tensor</param>
/// <param name="batchSize">Batch size of input data set</param>
/// <param name="graph">The instance of computing graph</param>
/// <returns>Transformered output tensor</returns>
public IWeightTensor Perform(IWeightTensor inputQ, IWeightTensor inputK, IWeightTensor inputV, IWeightTensor keyMask, int batchSize, IComputeGraph graph)
{
if (m_sharedQKV)
{
throw new ArgumentException($"Layer '{m_name}' is in shared QKV mode, please call antoher Perform function with single input tensor.");
}
using (IComputeGraph g = graph.CreateSubGraph($"{m_name}_MultiHeadAttention"))
{
int seqLenQ = inputQ.Rows / batchSize;
// SeqLenK must be euqal to SeqLenV
int seqLenK = inputK.Rows / batchSize;
int seqLenV = inputV.Rows / batchSize;
IWeightTensor inputQNorm = layerNormQ.Norm(inputQ, g);
//Input projections
float scale = 1.0f / (float)(m_inputDim);
IWeightTensor allQ = g.View(g.Affine(inputQNorm, Q, Qb, scale), dims: new long[] { batchSize, seqLenQ, m_multiHeadNum, m_d });
IWeightTensor allK = g.View(g.Affine(inputK, K, Kb, scale), dims: new long[] { batchSize, seqLenK, m_multiHeadNum, m_d });
IWeightTensor allV = g.View(g.Affine(inputV, V, Vb, scale), dims: new long[] { batchSize, seqLenV, m_multiHeadNum, m_d });
//Multi-head attentions
IWeightTensor Qs = g.View(g.Permute(allQ, 2, 0, 1, 3), dims: new long[] { m_multiHeadNum *batchSize, seqLenQ, m_d });
IWeightTensor Ks = g.View(g.Permute(allK, 2, 0, 3, 1), dims: new long[] { m_multiHeadNum *batchSize, m_d, seqLenK });
IWeightTensor Vs = g.View(g.Permute(allV, 2, 0, 1, 3), dims: new long[] { m_multiHeadNum *batchSize, seqLenV, m_d });
// Scaled softmax
scale = 1.0f / (float)(m_d);
IWeightTensor attn = g.MulBatch(Qs, Ks, m_multiHeadNum * batchSize, scale);
IWeightTensor softmax = g.Softmax(attn, keyMask, inPlace: true);
IWeightTensor o = g.View(g.MulBatch(softmax, Vs, m_multiHeadNum * batchSize), dims: new long[] { m_multiHeadNum, batchSize, seqLenQ, m_d });
IWeightTensor W = g.View(g.Permute(o, 1, 2, 0, 3), dims: new long[] { batchSize *seqLenQ, m_multiHeadNum *m_d });
// Output projection
IWeightTensor finalAttResults = g.Dropout(g.Affine(W, W0, b0), batchSize, m_dropoutRatio, inPlace: true);
return(graph.Add(finalAttResults, inputQ));
}
}
/// <summary>
/// Transformer encoder
/// </summary>
/// <param name="rawInputs"></param>
/// <param name="g"></param>
/// <returns></returns>
///
public IWeightTensor Decode(IWeightTensor tgtInputs, IWeightTensor encOutputBatchFirst, IWeightTensor tgtSelfMask, IWeightTensor decEncAttnMask, IWeightTensor tgtDimMask, int batchSize, IComputeGraph g)
{
int tgtSeqLen = tgtInputs.Rows / batchSize;
int srcSeqLen = encOutputBatchFirst.Rows / batchSize;
using (IWeightTensor posEmbedding = g.BuildPositionMatrix(tgtSeqLen, m_inputDim))
{
using (IWeightTensor posEmbeddingRepeat = g.RepeatRows(posEmbedding, batchSize, runGradient: false))
{
tgtInputs = g.AddMul(posEmbeddingRepeat, tgtInputs, (float)Math.Sqrt(m_inputDim), runGradientW1: false, runGradientW2: true);
}
}
tgtInputs = g.Dropout(tgtInputs, batchSize, m_dropoutRatio, inPlace: true);
var tgtSelfMaskRep = g.View(tgtSelfMask, dims: new long[] { 1, batchSize, tgtSeqLen, tgtSeqLen });
var tgtSelfMaskRepExp = g.Expand(tgtSelfMaskRep, dims: new long[] { m_multiHeadNum, batchSize, tgtSeqLen, tgtSeqLen });
var decEncAttnMaskRep = g.View(decEncAttnMask, dims: new long[] { 1, batchSize, tgtSeqLen, srcSeqLen });
var decEncAttnMaskRepExp = g.Expand(decEncAttnMaskRep, dims: new long[] { m_multiHeadNum, batchSize, tgtSeqLen, srcSeqLen });
var tgtSelfMaskRepExpView = g.View(tgtSelfMaskRepExp, dims: new long[] { m_multiHeadNum *batchSize *tgtSeqLen, tgtSeqLen });
var decEncAttnMaskRepExpView = g.View(decEncAttnMaskRepExp, dims: new long[] { m_multiHeadNum *batchSize *tgtSeqLen, srcSeqLen });
tgtSelfMaskRep.Dispose();
tgtSelfMaskRepExp.Dispose();
decEncAttnMaskRep.Dispose();
decEncAttnMaskRepExp.Dispose();
using (IComputeGraph subg = g.CreateSubGraph($"{m_name}_Decoder"))
{
for (int k = 0; k < m_selfAttns.Count; k++)
{
tgtInputs = g.MaskFill(tgtInputs, tgtDimMask, 0.0f);
tgtInputs = m_selfAttns[k].Perform(tgtInputs, tgtInputs, tgtInputs, tgtSelfMaskRepExpView, batchSize, subg);
tgtInputs = m_encAttns[k].Perform(tgtInputs, encOutputBatchFirst, encOutputBatchFirst, decEncAttnMaskRepExpView, batchSize, subg);
tgtInputs = m_posFFNs[k].Perform(tgtInputs, batchSize, subg);
}
tgtInputs.UnbindFromComputeGraph();
}
tgtInputs = layerNorm.Norm(tgtInputs, g);
// tgtInputs = m_decoderFFLayer.Process(tgtInputs, batchSize, g);
return(tgtInputs);
}
public IWeightTensor Perform(IWeightTensor input, int batchSize, IComputeGraph graph)
{
using IComputeGraph g = graph.CreateSubGraph($"{m_name}_PositionwiseFeedForward");
var inputNorm = layerNorm2.Norm(input, g);
//Feed forward
IWeightTensor ffnResult = feedForwardLayer1.Process(inputNorm, batchSize, g);
IWeightTensor reluFFNResult = g.Relu(ffnResult, inPlace: true);
IWeightTensor ffn2Result = feedForwardLayer2.Process(reluFFNResult, batchSize, g);
//Skip connection and layer normaliztion
IWeightTensor addFFNResult = graph.Add(ffn2Result, input, inPlace: true);
return(addFFNResult);
}
/// <summary>
/// Transformer encoder
/// </summary>
/// <param name="rawInputs"></param>
/// <param name="g"></param>
/// <returns></returns>
public IWeightTensor Encode(IWeightTensor inputs, int batchSize, IComputeGraph g, IWeightTensor srcSelfMask)
{
using (IComputeGraph subg = g.CreateSubGraph($"{m_name}_Encoder"))
{
for (int k = 0; k < m_encoders.Count; k++)
{
inputs = m_encoders[k].Perform(inputs, inputs, inputs, srcSelfMask, batchSize, subg);
inputs = m_posFFNs[k].Perform(inputs, batchSize, subg);
}
inputs.UnbindFromComputeGraph();
}
inputs = layerNorm.Norm(inputs, g);
return(inputs);
}
/// <summary>
/// Scaled multi-heads attention component with skip connectioned feed forward layers
/// </summary>
/// <param name="inputQ">The input Q tensor</param>
/// <param name="inputK">The input K tensor</param>
/// <param name="inputV">The input V tensor</param>
/// <param name="batchSize">Batch size of input data set</param>
/// <param name="graph">The instance of computing graph</param>
/// <returns>Transformered output tensor</returns>
public IWeightTensor Perform(IWeightTensor inputQ, IWeightTensor inputK, IWeightTensor inputV, IWeightTensor keyMask, int batchSize, IComputeGraph graph)
{
using (IComputeGraph g = graph.CreateSubGraph($"{m_name}_MultiHeadAttention"))
{
int seqLenQ = inputQ.Rows / batchSize;
// SeqLenK must be euqal to SeqLenV
int seqLenK = inputK.Rows / batchSize;
int seqLenV = inputV.Rows / batchSize;
IWeightTensor inputQNorm = layerNorm1.Norm(inputQ, g);
IWeightTensor inputKNorm = (inputK == inputQ) ? inputQNorm : inputK; // layerNorm1.Norm(inputK, g);
IWeightTensor inputVNorm = (inputK == inputV) ? inputKNorm : inputV; // layerNorm1.Norm(inputV, g);
//Input projections
IWeightTensor allQ = g.View(g.Affine(inputQNorm, Q, Qb), dims: new long[] { batchSize, seqLenQ, m_multiHeadNum, m_d });
IWeightTensor allK = g.View(g.Affine(inputKNorm, K, Kb), dims: new long[] { batchSize, seqLenK, m_multiHeadNum, m_d });
IWeightTensor allV = g.View(g.Affine(inputVNorm, V, Vb), dims: new long[] { batchSize, seqLenV, m_multiHeadNum, m_d });
//Multi-head attentions
IWeightTensor Qs = g.View(g.Permute(allQ, 2, 0, 1, 3), dims: new long[] { m_multiHeadNum *batchSize, seqLenQ, m_d });
IWeightTensor Ks = g.View(g.Permute(allK, 2, 0, 3, 1), dims: new long[] { m_multiHeadNum *batchSize, m_d, seqLenK });
IWeightTensor Vs = g.View(g.Permute(allV, 2, 0, 1, 3), dims: new long[] { m_multiHeadNum *batchSize, seqLenV, m_d });
// Scaled softmax
float scale = 1.0f / (float)Math.Sqrt(m_d);
IWeightTensor attn = g.MulBatch(Qs, Ks, m_multiHeadNum * batchSize, scale);
IWeightTensor attn2 = g.View(attn, dims: new long[] { m_multiHeadNum *batchSize *seqLenQ, seqLenK });
if (keyMask != null)
{
// attn2 = g.Add(attn2, mask, runGradient2: false);
attn2 = g.MaskFill(attn2, keyMask, -1e9f);
}
IWeightTensor softmax = g.Softmax(attn2, inPlace: true);
IWeightTensor softmax2 = g.View(softmax, dims: new long[] { m_multiHeadNum *batchSize, seqLenQ, seqLenK });
IWeightTensor o = g.View(g.MulBatch(softmax2, Vs, m_multiHeadNum * batchSize), dims: new long[] { m_multiHeadNum, batchSize, seqLenQ, m_d });
IWeightTensor W = g.View(g.Permute(o, 1, 2, 0, 3), dims: new long[] { batchSize *seqLenQ, m_multiHeadNum *m_d });
// Output projection
IWeightTensor finalAttResults = g.Dropout(g.Affine(W, W0, b0), batchSize, m_dropoutRatio, inPlace: true);
return(graph.Add(finalAttResults, inputQ));
}
}
/// <summary>
/// Scaled multi-heads attention component with skip connectioned feed forward layers
/// </summary>
/// <param name="input">The input tensor</param>
/// <param name="g">The instance of computing graph</param>
/// <returns></returns>
public IWeightTensor Perform(IWeightTensor input, int batchSize, IComputeGraph graph)
{
using (IComputeGraph g = graph.CreateSubGraph(m_name))
{
int seqLen = input.Rows / batchSize;
IWeightTensor nInput = layerNorm1.Norm(input, g);
//Input projections
IWeightTensor allQ = g.View(g.Affine(nInput, Q, Qb), batchSize, seqLen, m_multiHeadNum, m_d);
IWeightTensor allK = g.View(g.Affine(nInput, K, Kb), batchSize, seqLen, m_multiHeadNum, m_d);
IWeightTensor allV = g.View(g.Affine(nInput, V, Vb), batchSize, seqLen, m_multiHeadNum, m_d);
//Multi-head attentions
IWeightTensor Qs = g.View(g.Permute(allQ, 2, 0, 1, 3), m_multiHeadNum * batchSize, seqLen, m_d);
IWeightTensor Ks = g.View(g.Permute(allK, 2, 0, 3, 1), m_multiHeadNum * batchSize, m_d, seqLen);
IWeightTensor Vs = g.View(g.Permute(allV, 2, 0, 1, 3), m_multiHeadNum * batchSize, seqLen, m_d);
// Scaled softmax
float scale = 1.0f / (float)Math.Sqrt(m_d);
IWeightTensor attn = g.MulBatch(Qs, Ks, m_multiHeadNum * batchSize, scale);
IWeightTensor attn2 = g.View(attn, m_multiHeadNum * batchSize * seqLen, seqLen);
IWeightTensor softmax = g.Softmax(attn2, inPlace: true);
IWeightTensor softmax2 = g.View(softmax, m_multiHeadNum * batchSize, seqLen, seqLen);
IWeightTensor o = g.View(g.MulBatch(softmax2, Vs, m_multiHeadNum * batchSize), m_multiHeadNum, batchSize, seqLen, m_d);
IWeightTensor W = g.View(g.Permute(o, 1, 2, 0, 3), batchSize * seqLen, m_multiHeadNum * m_d);
// Output projection
IWeightTensor finalAttResults = g.Dropout(g.Affine(W, W0, b0), batchSize, m_dropoutRatio, inPlace: true);
//Skip connection and layer normaliztion
IWeightTensor normAddedAttResult = layerNorm2.AddNorm(finalAttResults, input, g);
//Feed forward
IWeightTensor ffnResult = feedForwardLayer1.Process(normAddedAttResult, batchSize, g);
IWeightTensor reluFFNResult = g.Relu(ffnResult);
IWeightTensor ffn2Result = feedForwardLayer2.Process(reluFFNResult, batchSize, g);
//Skip connection and layer normaliztion
IWeightTensor addFFNResult = graph.Add(ffn2Result, normAddedAttResult);
return(addFFNResult);
}
}
/// <summary>
/// Transformer encoder
/// </summary>
/// <param name="rawInputs"></param>
/// <param name="g"></param>
/// <returns></returns>
///
public IWeightTensor Decode(IWeightTensor tgtInputs, IWeightTensor encOutputBatchFirst, IWeightTensor tgtSelfMask, IWeightTensor srcTgtMask, int batchSize, IComputeGraph g)
{
using (IComputeGraph subg = g.CreateSubGraph($"{m_name}_Decoder"))
{
for (int k = 0; k < m_selfAttns.Count; k++)
{
tgtInputs = m_selfAttns[k].Perform(tgtInputs, tgtInputs, tgtInputs, tgtSelfMask, batchSize, subg);
tgtInputs = m_encAttns[k].Perform(tgtInputs, encOutputBatchFirst, encOutputBatchFirst, srcTgtMask, batchSize, subg);
tgtInputs = m_posFFNs[k].Perform(tgtInputs, batchSize, subg);
}
tgtInputs = layerNorm.Norm(tgtInputs, subg);
tgtInputs.UnbindFromComputeGraph();
}
tgtInputs = m_decoderFFLayer.Process(tgtInputs, batchSize, g);
return(tgtInputs);
}
/// <summary>
/// Transformer encoder
/// </summary>
/// <param name="rawInputs"></param>
/// <param name="g"></param>
/// <returns></returns>
public IWeightTensor Encode(IWeightTensor inputs, IWeightTensor selfMask, IWeightTensor dimMask, int batchSize, IComputeGraph g)
{
int seqLen = inputs.Rows / batchSize;
using (IWeightTensor posEmbedding = g.BuildPositionMatrix(seqLen, m_inputDim))
{
using (IWeightTensor posEmbeddingRepeat = g.RepeatRows(posEmbedding, batchSize, runGradient: false))
{
inputs = g.AddMul(posEmbeddingRepeat, inputs, (float)Math.Sqrt(m_inputDim), runGradientW1: false, runGradientW2: true);
}
}
inputs = g.Dropout(inputs, batchSize, m_dropoutRatio, inPlace: true);
var selfMaskRep = g.View(selfMask, dims: new long[] { 1, batchSize, seqLen, seqLen });
var multiHeadhSelfMaskRep = g.Expand(selfMaskRep, dims: new long[] { m_multiHeadNum, batchSize, seqLen, seqLen });
var multiHeadhSelfMaskRepView = g.View(multiHeadhSelfMaskRep, dims: new long[] { m_multiHeadNum *batchSize *seqLen, seqLen });
selfMaskRep.Dispose();
multiHeadhSelfMaskRep.Dispose();
using (IComputeGraph subg = g.CreateSubGraph($"{m_name}_Encoder"))
{
for (int k = 0; k < m_encoders.Count; k++)
{
inputs = g.MaskFill(inputs, dimMask, 0.0f);
inputs = m_encoders[k].Perform(inputs, inputs, inputs, multiHeadhSelfMaskRepView, batchSize, subg);
inputs = m_posFFNs[k].Perform(inputs, batchSize, subg);
}
inputs.UnbindFromComputeGraph();
}
inputs = layerNorm.Norm(inputs, g);
return(inputs);
}
/// <summary>
/// Scaled multi-heads attention component with skip connectioned feed forward layers
/// </summary>
/// <param name="inputQ">The input Q tensor</param>
/// <param name="inputK">The input K tensor</param>
/// <param name="inputV">The input V tensor</param>
/// <param name="keyMask">The mask for softmax</param>
/// <param name="batchSize">Batch size of input data set</param>
/// <param name="graph">The instance of computing graph</param>
/// <returns>Transformered output tensor</returns>
public IWeightTensor Perform(IWeightTensor inputQ, IWeightTensor inputK, IWeightTensor inputV, IWeightTensor keyMask, int batchSize, IComputeGraph graph)
{
using (IComputeGraph g = graph.CreateSubGraph($"{m_name}_MultiHeadAttention"))
{
int seqLenQ = inputQ.Rows / batchSize;
// SeqLenK must be euqal to SeqLenV
int seqLenK = inputK.Rows / batchSize;
int seqLenV = inputV.Rows / batchSize;
IWeightTensor inputQNorm = layerNormQ.Norm(inputQ, g);
if (inputK == inputQ)
{
inputK = inputQNorm;
}
if (inputV == inputQ)
{
inputV = inputQNorm;
}
//Input projections
float scale = 1.0f;
IWeightTensor allQ = g.View(g.Affine(inputQNorm, Q, Qb, scale), dims: new long[] { batchSize, seqLenQ, m_multiHeadNum, m_d });
IWeightTensor allK = g.View(g.Affine(inputK, K, Kb, scale), dims: new long[] { batchSize, seqLenK, m_multiHeadNum, m_d });
IWeightTensor allV = g.View(g.Affine(inputV, V, Vb, scale), dims: new long[] { batchSize, seqLenV, m_multiHeadNum, m_d });
//Multi-head attentions
IWeightTensor Qs = g.View(g.AsContiguous(g.Transpose(allQ, 1, 2)), dims: new long[] { batchSize *m_multiHeadNum, seqLenQ, m_d });
IWeightTensor Ks = g.View(g.AsContiguous(g.Transpose(g.Transpose(allK, 1, 2), 2, 3)), dims: new long[] { batchSize *m_multiHeadNum, m_d, seqLenK });
IWeightTensor Vs = g.View(g.AsContiguous(g.Transpose(allV, 1, 2)), dims: new long[] { batchSize *m_multiHeadNum, seqLenV, m_d });
// Scaled softmax
scale = 1.0f / (float)(Math.Sqrt(m_d));
IWeightTensor attn = g.MulBatch(Qs, Ks, batchSize * m_multiHeadNum, scale);
if (keyMask != null)
{
using (var keyMaskView = g.View(keyMask, runGradient: false, dims: new long[] { batchSize, 1, seqLenQ, seqLenK }))
{
using (var keyMaskViewExp = g.Expand(keyMaskView, runGradient: false, dims: new long[] { batchSize, m_multiHeadNum, seqLenQ, seqLenK }))
{
using (var keyMaskViewExpConti = g.AsContiguous(keyMaskViewExp, runGradient: false))
{
using (var keyMaskViewExpContiView = g.View(keyMaskViewExpConti, runGradient: false, dims: new long[] { batchSize *m_multiHeadNum, seqLenQ, seqLenK }))
{
attn = g.Add(attn, keyMaskViewExpContiView, runGradient1: true, runGradient2: false);
}
}
}
}
}
IWeightTensor softmax = g.Softmax(attn, inPlace: true);
IWeightTensor o = g.View(g.MulBatch(softmax, Vs, batchSize * m_multiHeadNum), dims: new long[] { batchSize, m_multiHeadNum, seqLenQ, m_d });
IWeightTensor W = g.View(g.AsContiguous(g.Transpose(o, 1, 2)), dims: new long[] { batchSize *seqLenQ, m_multiHeadNum *m_d });
// Output projection
IWeightTensor finalAttResults = g.Dropout(g.Affine(W, W0, b0), batchSize, m_dropoutRatio, inPlace: true);
return(graph.Add(finalAttResults, inputQ));
}
}
