Thyra DefaultMultipliedLinearOp: Caching of intermediate vectors

Signed-off-by: Christian Glusa <[email protected]>
trilinos · Jan 21, 2025 · fb5e877 · fb5e877
1 parent bc6496e
commit fb5e877
Show file tree

Hide file tree

Showing 2 changed files with 23 additions and 2 deletions.
diff --git a/.../core/src/support/operator_vector/client_support/Thyra_DefaultMultipliedLinearOp_decl.hpp b/.../core/src/support/operator_vector/client_support/Thyra_DefaultMultipliedLinearOp_decl.hpp
@@ -212,6 +212,8 @@ class DefaultMultipliedLinearOp : virtual public MultipliedLinearOpBase<Scalar>
    */
   bool opSupportedImpl(EOpTransp M_trans) const;
 
+  void allocateVecs(const Ordinal dim) const;
+
   /** \brief . */
   void applyImpl(
     const EOpTransp M_trans,
@@ -228,6 +230,7 @@ class DefaultMultipliedLinearOp : virtual public MultipliedLinearOpBase<Scalar>
 private:
 
   Array<Teuchos::ConstNonconstObjectContainer<LinearOpBase<Scalar> > > Ops_;
+  mutable std::vector<Teuchos::RCP<MultiVectorBase<Scalar> > > T_k_;
 
   inline void assertInitialized() const;
   inline std::string getClassName() const;

diff --git a/...a/core/src/support/operator_vector/client_support/Thyra_DefaultMultipliedLinearOp_def.hpp b/...a/core/src/support/operator_vector/client_support/Thyra_DefaultMultipliedLinearOp_def.hpp
@@ -236,6 +236,23 @@ bool DefaultMultipliedLinearOp<Scalar>::opSupportedImpl(EOpTransp M_trans) const
   // ToDo: Cache these?
 }
 
+template<class Scalar>
+void DefaultMultipliedLinearOp<Scalar>::allocateVecs(const Ordinal dim) const {
+  const int nOps = Ops_.size();
+  if ((T_k_.size() != nOps+1) || ((nOps > 0) && (T_k_[0]->domain()->dim() != dim))) {
+    // op[0]->range
+    // op[0]->domain == op[1]->range
+    // ...
+    // op[nOps-2]->domain == op[nOps-1]->range
+    // op[nOps-1]->domain
+    T_k_.resize(0);
+    for( int k = 0; k < nOps; ++k ) {
+      T_k_.push_back(createMembers(getOp(k)->range(), dim));
+    }
+    T_k_.push_back(createMembers(getOp(nOps-1)->domain(), dim));
+  }
+}
+
 
 template<class Scalar>
 void DefaultMultipliedLinearOp<Scalar>::applyImpl(
@@ -255,6 +272,7 @@ void DefaultMultipliedLinearOp<Scalar>::applyImpl(
 #endif // TEUCHOS_DEBUG  
   const int nOps = Ops_.size();
   const Ordinal m = X.domain()->dim();
+  allocateVecs(m);
   if( real_trans(M_trans)==NOTRANS ) {
     //
     // Y = alpha * M * X + beta*Y
@@ -265,7 +283,7 @@ void DefaultMultipliedLinearOp<Scalar>::applyImpl(
     for( int k = nOps-1; k >= 0; --k ) {
       RCP<MultiVectorBase<Scalar> > Y_k;
       RCP<const MultiVectorBase<Scalar> > X_k;
-      if(k==0) Y_k = rcpFromPtr(Y);  else Y_k = T_k = createMembers(getOp(k)->range(), m);
+      if(k==0) Y_k = rcpFromPtr(Y);  else Y_k = T_k = T_k_[k];
       if(k==nOps-1) X_k = rcpFromRef(X); else X_k = T_kp1;
       if( k > 0 )
         Thyra::apply(*getOp(k), M_trans, *X_k, Y_k.ptr());
@@ -284,7 +302,7 @@ void DefaultMultipliedLinearOp<Scalar>::applyImpl(
     for( int k = 0; k <= nOps-1; ++k ) {
       RCP<MultiVectorBase<Scalar> >         Y_k;
       RCP<const MultiVectorBase<Scalar> >   X_k;
-      if(k==nOps-1) Y_k = rcpFromPtr(Y);  else Y_k = T_k = createMembers(getOp(k)->domain(), m);
+      if(k==nOps-1) Y_k = rcpFromPtr(Y);  else Y_k = T_k = T_k_[k+1];
       if(k==0) X_k = rcpFromRef(X); else X_k = T_km1;
       if( k < nOps-1 )
         Thyra::apply(*getOp(k), M_trans, *X_k, Y_k.ptr());