Add Problem::IsParameterBlockPresent.

This allows the user to query the Problem to see if a
parameter block is already present or not.

Change-Id: If786f6c008cc644f3398597901d718d12a6d865d

include/ceres/problem.h

@@ -349,6 +349,9 @@ class Problem {
   // block, then ParameterBlockLocalSize = ParameterBlockSize.
   int ParameterBlockLocalSize(const double* values) const;
 
+  // Is the given parameter block present in this problem or not?
+  bool HasParameterBlock(const double* values) const;
+
   // Fills the passed parameter_blocks vector with pointers to the
   // parameter blocks currently in the problem. After this call,
   // parameter_block.size() == NumParameterBlocks.

internal/ceres/problem.cc

@@ -231,6 +231,10 @@ int Problem::ParameterBlockLocalSize(const double* parameter_block) const {
   return problem_impl_->ParameterBlockLocalSize(parameter_block);
 };
 
+bool Problem::HasParameterBlock(const double* values) const {
+  return problem_impl_->HasParameterBlock(values);
+}
+
 void Problem::GetParameterBlocks(vector<double*>* parameter_blocks) const {
   problem_impl_->GetParameterBlocks(parameter_blocks);
 }

internal/ceres/problem_impl.cc

@@ -791,6 +791,11 @@ int ProblemImpl::ParameterBlockLocalSize(const double* parameter_block) const {
       parameter_block_map_, const_cast<double*>(parameter_block))->LocalSize();
 };
 
+bool ProblemImpl::HasParameterBlock(const double* parameter_block) const {
+  return (parameter_block_map_.find(const_cast<double*>(parameter_block)) !=
+          parameter_block_map_.end());
+}
+
 void ProblemImpl::GetParameterBlocks(vector<double*>* parameter_blocks) const {
   CHECK_NOTNULL(parameter_blocks);
   parameter_blocks->resize(0);

internal/ceres/problem_impl.h

@@ -147,6 +147,9 @@ class ProblemImpl {
 
   int ParameterBlockSize(const double* parameter_block) const;
   int ParameterBlockLocalSize(const double* parameter_block) const;
+
+  bool HasParameterBlock(const double* parameter_block) const;
+
   void GetParameterBlocks(vector<double*>* parameter_blocks) const;
   void GetResidualBlocks(vector<ResidualBlockId>* residual_blocks) const;
 

internal/ceres/problem_test.cc

@@ -556,7 +556,9 @@ TEST(Problem, ParameterBlockQueryTest) {
   EXPECT_TRUE(parameter_blocks[0] == x || parameter_blocks[0] == y);
   EXPECT_TRUE(parameter_blocks[1] == x || parameter_blocks[1] == y);
 
+  EXPECT_TRUE(problem.HasParameterBlock(x));
   problem.RemoveParameterBlock(x);
+  EXPECT_FALSE(problem.HasParameterBlock(x));
   problem.GetParameterBlocks(&parameter_blocks);
   EXPECT_EQ(parameter_blocks.size(), 1);
   EXPECT_TRUE(parameter_blocks[0] == y);