Better error reporting in the modeling API.

More informative error when user passes an
unknown parameter block to Problem methods.

Change-Id: I517360e4b0b55814904ca3e664877d76ad3f59e8

internal/ceres/problem_impl.cc

diff --git a/internal/ceres/problem_impl.cc b/internal/ceres/problem_impl.cc
index 21d1144..519e12b 100644
--- a/internal/ceres/problem_impl.cc
+++ b/internal/ceres/problem_impl.cc
@@ -56,6 +56,15 @@
 
 typedef map<double*, internal::ParameterBlock*> ParameterMap;
 
+internal::ParameterBlock* FindParameterBlockOrDie(
+    const ParameterMap& parameter_map,
+    double* parameter_block) {
+  ParameterMap::const_iterator it = parameter_map.find(parameter_block);
+  CHECK(it != parameter_map.end())
+      << "Parameter block not found: " << parameter_block;
+  return it->second;
+}
+
 // Returns true if two regions of memory, a and b, with sizes size_a and size_b
 // respectively, overlap.
 static bool RegionsAlias(const double* a, int size_a,
@@ -471,7 +480,8 @@
 }
 
 void ProblemImpl::RemoveParameterBlock(double* values) {
-  ParameterBlock* parameter_block = FindOrDie(parameter_block_map_, values);
+  ParameterBlock* parameter_block =
+      FindParameterBlockOrDie(parameter_block_map_, values);
 
   if (options_.enable_fast_parameter_block_removal) {
     // Copy the dependent residuals from the parameter block because the set of
@@ -503,17 +513,17 @@
 }
 
 void ProblemImpl::SetParameterBlockConstant(double* values) {
-  FindOrDie(parameter_block_map_, values)->SetConstant();
+  FindParameterBlockOrDie(parameter_block_map_, values)->SetConstant();
 }
 
 void ProblemImpl::SetParameterBlockVariable(double* values) {
-  FindOrDie(parameter_block_map_, values)->SetVarying();
+  FindParameterBlockOrDie(parameter_block_map_, values)->SetVarying();
 }
 
 void ProblemImpl::SetParameterization(
     double* values,
     LocalParameterization* local_parameterization) {
-  FindOrDie(parameter_block_map_, values)
+  FindParameterBlockOrDie(parameter_block_map_, values)
       ->SetParameterization(local_parameterization);
 }
 
@@ -557,7 +567,8 @@
     parameter_blocks.resize(parameter_block_ptrs.size());
     for (int i = 0; i < parameter_block_ptrs.size(); ++i) {
       parameter_blocks[i] =
-          FindOrDie(parameter_block_map_, parameter_block_ptrs[i]);
+          FindParameterBlockOrDie(parameter_block_map_,
+                                  parameter_block_ptrs[i]);
     }
 
     // 2. The user may have only supplied a subset of parameter

internal/ceres/problem_test.cc

diff --git a/internal/ceres/problem_test.cc b/internal/ceres/problem_test.cc
index 5f3bc94..ab40e05 100644
--- a/internal/ceres/problem_test.cc
+++ b/internal/ceres/problem_test.cc
@@ -457,6 +457,51 @@
   double y[4], z[5], w[3];
 };
 
+TEST(Problem, SetParameterBlockConstantWithUnknownPtrDies) {
+  double x[3];
+  double y[2];
+
+  Problem problem;
+  problem.AddParameterBlock(x, 3);
+
+  EXPECT_DEATH_IF_SUPPORTED(problem.SetParameterBlockConstant(y),
+                            "Parameter block not found:");
+}
+
+TEST(Problem, SetParameterBlockVariableWithUnknownPtrDies) {
+  double x[3];
+  double y[2];
+
+  Problem problem;
+  problem.AddParameterBlock(x, 3);
+
+  EXPECT_DEATH_IF_SUPPORTED(problem.SetParameterBlockVariable(y),
+                            "Parameter block not found:");
+}
+
+TEST(Problem, SetLocalParameterizationWithUnknownPtrDies) {
+  double x[3];
+  double y[2];
+
+  Problem problem;
+  problem.AddParameterBlock(x, 3);
+
+  EXPECT_DEATH_IF_SUPPORTED(
+      problem.SetParameterization(y, new IdentityParameterization(3)),
+      "Parameter block not found:");
+}
+
+TEST(Problem, RemoveParameterBlockWithUnknownPtrDies) {
+  double x[3];
+  double y[2];
+
+  Problem problem;
+  problem.AddParameterBlock(x, 3);
+
+  EXPECT_DEATH_IF_SUPPORTED(
+      problem.RemoveParameterBlock(y), "Parameter block not found:");
+}
+
 TEST_P(DynamicProblem, RemoveParameterBlockWithNoResiduals) {
   problem->AddParameterBlock(y, 4);
   problem->AddParameterBlock(z, 5);