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

diff --git a/include/ceres/problem.h b/include/ceres/problem.h
index bed792a..b8759eb 100644
--- a/include/ceres/problem.h
+++ b/include/ceres/problem.h

@@ -349,6 +349,9 @@
   // 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.

diff --git a/internal/ceres/problem.cc b/internal/ceres/problem.cc
index 9bdc1ef..674694d 100644
--- a/internal/ceres/problem.cc
+++ b/internal/ceres/problem.cc

@@ -231,6 +231,10 @@
   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);
 }

diff --git a/internal/ceres/problem_impl.cc b/internal/ceres/problem_impl.cc
index d9fb2af..7c86efb 100644
--- a/internal/ceres/problem_impl.cc
+++ b/internal/ceres/problem_impl.cc

@@ -791,6 +791,11 @@
       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);

diff --git a/internal/ceres/problem_impl.h b/internal/ceres/problem_impl.h
index e846c03..7b5547b 100644
--- a/internal/ceres/problem_impl.h
+++ b/internal/ceres/problem_impl.h

@@ -147,6 +147,9 @@
 
   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;
 

diff --git a/internal/ceres/problem_test.cc b/internal/ceres/problem_test.cc
index eb75e3a..db082ec 100644
--- a/internal/ceres/problem_test.cc
+++ b/internal/ceres/problem_test.cc

@@ -556,7 +556,9 @@
   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);