commit 2f1454faf2fe4ba77fc56fe250783117c09e26c3
author Sameer Agarwal <sameeragarwal@google.com> Thu Jun 13 23:34:46 2013 -0700
committer Sameer Agarwal <sameeragarwal@google.com> Thu Jun 13 23:49:19 2013 -0700
tree 512c5a4d0b878e72a42ba20940d0f2870ea50214
parent 85b7e9d3c1f8251b2aac5e87832cb53a42e8e7ab

Add a templated TypedPreconditioner class.

This sets the stage of preconditioners that can utilize
different kinds of matrix layouts, just like the LinearSolver
class hierarchy.

Change-Id: I3579cf344bcd2eeeecb1ae621cab02a3c9a0f920

internal/ceres/preconditioner.h

diff --git a/internal/ceres/preconditioner.h b/internal/ceres/preconditioner.h
index 7206536..cb0a381 100644
--- a/internal/ceres/preconditioner.h
+++ b/internal/ceres/preconditioner.h
@@ -32,6 +32,8 @@
 #define CERES_INTERNAL_PRECONDITIONER_H_
 
 #include <vector>
+#include "ceres/casts.h"
+#include "ceres/compressed_row_sparse_matrix.h"
 #include "ceres/linear_operator.h"
 #include "ceres/sparse_matrix.h"
 
@@ -105,7 +107,7 @@
   //
   // D can be NULL, in which case its interpreted as a diagonal matrix
   // of size zero.
-  virtual bool Update(const BlockSparseMatrix& A, const double* D) = 0;
+  virtual bool Update(const LinearOperator& A, const double* D) = 0;
 
   // LinearOperator interface. Since the operator is symmetric,
   // LeftMultiply and num_cols are just calls to RightMultiply and
@@ -122,19 +124,40 @@
   }
 };
 
+// This templated subclass of Preconditioner serves as a base class for
+// other preconditioners that depend on the particular matrix layout of
+// the underlying linear operator.
+template <typename MatrixType>
+class TypedPreconditioner : public Preconditioner {
+ public:
+  virtual ~TypedPreconditioner() {}
+  virtual bool Update(const LinearOperator& A, const double* D) {
+    return UpdateImpl(*down_cast<const MatrixType*>(&A), D);
+  }
+
+ private:
+  virtual bool UpdateImpl(const MatrixType& A, const double* D) = 0;
+};
+
+// Preconditioners that depend on acccess to the low level structure
+// of a SparseMatrix.
+typedef TypedPreconditioner<SparseMatrix>              SparseMatrixPreconditioner;               // NOLINT
+typedef TypedPreconditioner<BlockSparseMatrix>         BlockSparseMatrixPreconditioner;          // NOLINT
+typedef TypedPreconditioner<CompressedRowSparseMatrix> CompressedRowSparseMatrixPreconditioner;  // NOLINT
+
 // Wrap a SparseMatrix object as a preconditioner.
-class SparseMatrixPreconditionerWrapper : public Preconditioner {
+class SparseMatrixPreconditionerWrapper : public SparseMatrixPreconditioner {
  public:
   // Wrapper does NOT take ownership of the matrix pointer.
   explicit SparseMatrixPreconditionerWrapper(const SparseMatrix* matrix);
   virtual ~SparseMatrixPreconditionerWrapper();
 
   // Preconditioner interface
-  virtual bool Update(const BlockSparseMatrix& A, const double* D);
   virtual void RightMultiply(const double* x, double* y) const;
   virtual int num_rows() const;
 
  private:
+  virtual bool UpdateImpl(const SparseMatrix& A, const double* D);
   const SparseMatrix* matrix_;
 };