move logits to its own file

src/layers/embedding.h

@@ -4,6 +4,8 @@
 
 namespace marian {
 
+class FactoredVocab;
+
 // A regular embedding layer.
 // Note that this also applies dropout if the option is passed (pass 0 when in inference mode).
 // It is best to not use Embedding directly, but rather via getEmbeddingLayer() in

src/layers/generic.h

@@ -97,72 +97,6 @@ public:
   Ptr<IEmbeddingLayer> getEmbeddingLayer(bool ulr = false) const;
 };
 
-class FactoredVocab;
-
-// To support factors, any output projection (that is followed by a softmax) must
-// retain multiple outputs, one for each factor. Such layer returns not a single Expr,
-// but a Logits object that contains multiple.
-// This allows to compute softmax values in a factored manner, where we never create
-// a fully expanded list of all factor combinations.
-class RationalLoss;
-class Logits {
-public:
-    Logits() {}
-    explicit Logits(Ptr<RationalLoss> logits) { // single-output constructor
-      logits_.push_back(logits);
-    }
-    explicit Logits(Expr logits); // single-output constructor from Expr only (RationalLoss has no count)
-    Logits(std::vector<Ptr<RationalLoss>>&& logits, Ptr<FactoredVocab> embeddingFactorMapping) // factored-output constructor
-      : logits_(std::move(logits)), factoredVocab_(embeddingFactorMapping) {}
-    Expr getLogits() const; // assume it holds logits: get them, possibly aggregating over factors
-    Expr getFactoredLogits(size_t groupIndex, Ptr<data::Shortlist> shortlist = nullptr, const std::vector<IndexType>& hypIndices = {}, size_t beamSize = 0) const; // get logits for only one factor group, with optional reshuffle
-    //Ptr<RationalLoss> getRationalLoss() const; // assume it holds a loss: get that
-    Expr applyLossFunction(const Words& labels, const std::function<Expr(Expr/*logits*/,Expr/*indices*/)>& lossFn) const;
-    Logits applyUnaryFunction(const std::function<Expr(Expr)>& f) const; // clone this but apply f to all loss values
-    Logits applyUnaryFunctions(const std::function<Expr(Expr)>& f1, const std::function<Expr(Expr)>& fother) const; // clone this but apply f1 to first and fother to to all other values
-
-    struct MaskedFactorIndices {
-      std::vector<WordIndex> indices; // factor index, or 0 if masked
-      std::vector<float> masks;
-      void reserve(size_t n) { indices.reserve(n); masks.reserve(n); }
-      void push_back(size_t factorIndex); // push back into both arrays, setting mask and index to 0 for invalid entries
-      MaskedFactorIndices() {}
-      MaskedFactorIndices(const Words& words) { indices = toWordIndexVector(words); } // we can leave masks uninitialized for this special use case
-    };
-    std::vector<MaskedFactorIndices> factorizeWords(const Words& words) const; // breaks encoded Word into individual factor indices
-    Tensor getFactoredLogitsTensor(size_t factorGroup) const; // used for breakDown() only
-    size_t getNumFactorGroups() const { return logits_.size(); }
-    bool empty() const { return logits_.empty(); }
-    Logits withCounts(const Expr& count) const; // create new Logits with 'count' implanted into all logits_
-private:
-    // helper functions
-    Ptr<ExpressionGraph> graph() const;
-    Expr constant(const Shape& shape, const std::vector<float>&    data) const { return graph()->constant(shape, inits::fromVector(data)); }
-    Expr constant(const Shape& shape, const std::vector<uint32_t>& data) const { return graph()->constant(shape, inits::fromVector(data));  }
-    template<typename T> Expr constant(const std::vector<T>& data) const { return constant(Shape{(int)data.size()}, data); } // same as constant() but assuming vector
-    Expr indices(const std::vector<uint32_t>& data) const { return graph()->indices(data); } // actually the same as constant(data) for this data type
-    std::vector<float> getFactorMasks(size_t factorGroup, const std::vector<WordIndex>& indices) const;
-private:
-    // members
-    // @TODO: we don't use the RationalLoss component anymore, can be removed again, and replaced just by the Expr
-    std::vector<Ptr<RationalLoss>> logits_; // [group id][B..., num factors in group]
-    Ptr<FactoredVocab> factoredVocab_;
-};
-
-// Unary function that returns a Logits object
-// Also implements IUnaryLayer, since Logits can be cast to Expr.
-// This interface is implemented by all layers that are of the form of a unary function
-// that returns multiple logits, to support factors.
-struct IUnaryLogitLayer : public IUnaryLayer {
-  virtual Logits applyAsLogits(Expr) = 0;
-  virtual Logits applyAsLogits(const std::vector<Expr>& es) {
-    ABORT_IF(es.size() > 1, "Not implemented"); // simple stub
-    return applyAsLogits(es.front());
-  }
-  virtual Expr apply(Expr e) override { return applyAsLogits(e).getLogits(); }
-  virtual Expr apply(const std::vector<Expr>& es) override { return applyAsLogits(es).getLogits(); }
-};
-
 namespace mlp {
 
 class Dense : public LayerBase, public IUnaryLayer {

src/layers/loss.h

@@ -1,7 +1,7 @@
 #pragma once
 
 #include "graph/expression_operators.h"
-#include "layers/generic.h" // for Logits (Frank's factor hack)
+#include "layers/logits.h" // for Logits (Frank's factor hack)
 #include "data/types.h"
 
 namespace marian {

src/layers/output.h

@@ -2,6 +2,7 @@
 
 #include "marian.h"
 #include "generic.h"
+#include "logits.h"
 #include "data/shortlist.h"
 #include "layers/factory.h"
 

src/models/states.h

@@ -1,7 +1,7 @@
 #pragma once
 
 #include "marian.h"
-#include "layers/generic.h" // @HACK: for factored embeddings only so far
+#include "layers/logits.h" // @HACK: for factored embeddings only so far
 #include "rnn/types.h"
 
 namespace marian {