Add sparse input support for factorization machine layer

paddle/gserver/layers/FactorizationMachineLayer.cpp

@@ -104,15 +104,21 @@ void FactorizationMachineLayer::backward(const UpdateCallback& callback) {
       CpuSparseMatrix* tmpIn_s = dynamic_cast<CpuSparseMatrix*>(tmpIn.get());
       tmpIn_s->copyFrom(*inputV_s);
       tmpIn_s->rowScale(0, *inputV_s, *oGrad);
-      latentVectors_->getWGrad()->mul(*tmpIn->getTranspose(), *tmpMul_, 1, 1);
+      latentVectors_->getWGrad()->mul(*tmpIn_s->getTranspose(), *tmpMul_, 1, 1);
       tmpIn_s->rowScale(0, *x2_s, *oGrad);
+
+      MatrixPtr ones = Matrix::create(1, inputV->getHeight(), false, useGpu_);
+      ones->zeroMem();
+      ones->add(-1);
+      tmpSum->mul(*ones, *tmpIn_s, 1, 0);
     } else {
       tmpIn->rowScale(0, *inputV, *oGrad);
       latentVectors_->getWGrad()->mul(*tmpIn->getTranspose(), *tmpMul_, 1, 1);
       tmpIn->rowScale(0, *x2_, *oGrad);
+
+      tmpSum->sumCols(*tmpIn, -1, 0);
     }
 
-    tmpSum->sumCols(*tmpIn, -1, 0);
     latentVectors_->getWGrad()->addRowScale(
         0, *latentVectors_->getW(), *tmpSum_T);