diff --git a/internal/ceres/CMakeLists.txt b/internal/ceres/CMakeLists.txt
index cd4e6ac..862b7cf 100644
--- a/internal/ceres/CMakeLists.txt
+++ b/internal/ceres/CMakeLists.txt
@@ -63,6 +63,7 @@
     local_parameterization.cc
     loss_function.cc
     normal_prior.cc
+    ordering.cc
     partitioned_matrix_view.cc
     polynomial_solver.cc
     problem.cc
@@ -232,6 +233,7 @@
   CERES_TEST(minimizer)
   CERES_TEST(normal_prior)
   CERES_TEST(numeric_diff_cost_function)
+  CERES_TEST(ordering)
   CERES_TEST(parameter_block)
   CERES_TEST(partitioned_matrix_view)
   CERES_TEST(polynomial_solver)
diff --git a/internal/ceres/ordering.cc b/internal/ceres/ordering.cc
new file mode 100644
index 0000000..8b53ea5
--- /dev/null
+++ b/internal/ceres/ordering.cc
@@ -0,0 +1,89 @@
+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2012 Google Inc. All rights reserved.
+// http://code.google.com/p/ceres-solver/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+//   this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright notice,
+//   this list of conditions and the following disclaimer in the documentation
+//   and/or other materials provided with the distribution.
+// * Neither the name of Google Inc. nor the names of its contributors may be
+//   used to endorse or promote products derived from this software without
+//   specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: sameeragarwal@google.com (Sameer Agarwal)
+
+#include <map>
+#include <set>
+#include "ceres/internal/port.h"
+#include "ceres/ordering.h"
+#include "glog/logging.h"
+
+namespace ceres {
+
+void Ordering::AddParameterBlockToGroup(double* parameter_block, int group_id) {
+  const map<double*, int>::const_iterator it =
+      parameter_block_to_group_id_.find(parameter_block);
+
+  if (it != parameter_block_to_group_id_.end()) {
+    group_id_to_parameter_blocks_[it->second].erase(parameter_block);
+    if (group_id_to_parameter_blocks_[it->second].size() == 0) {
+      group_id_to_parameter_blocks_.erase(it->second);
+    }
+  }
+
+  parameter_block_to_group_id_[parameter_block] = group_id;
+  group_id_to_parameter_blocks_[group_id].insert(parameter_block);
+}
+
+void Ordering::RemoveParameterBlock(double* parameter_block) {
+  const int current_group_id = GroupIdForParameterBlock(parameter_block);
+  group_id_to_parameter_blocks_[current_group_id].erase(parameter_block);
+  if (group_id_to_parameter_blocks_[current_group_id].size() == 0) {
+    group_id_to_parameter_blocks_.erase(current_group_id);
+  }
+
+  parameter_block_to_group_id_.erase(parameter_block);
+}
+
+int Ordering::GroupIdForParameterBlock(double* parameter_block) const {
+  const map<double*, int>::const_iterator it =
+      parameter_block_to_group_id_.find(parameter_block);
+  CHECK(it !=  parameter_block_to_group_id_.end())
+      << "Tried finding the group id of a parameter block unknown to "
+      << "the ordering: " << parameter_block;
+  return it->second;
+}
+
+int Ordering::NumParameterBlocks() const {
+  return parameter_block_to_group_id_.size();
+}
+
+int Ordering::NumGroups() const { return group_id_to_parameter_blocks_.size(); }
+
+int Ordering::GroupSize(int group_id) const {
+  map<int, set<double*> >::const_iterator it =
+      group_id_to_parameter_blocks_.find(group_id);
+  return (it ==  group_id_to_parameter_blocks_.end()) ? 0 : it->second.size();
+}
+
+const map<int, set<double*> >& Ordering::group_id_to_parameter_blocks() const {
+  return group_id_to_parameter_blocks_;
+}
+
+}  // namespace ceres
diff --git a/internal/ceres/ordering_test.cc b/internal/ceres/ordering_test.cc
new file mode 100644
index 0000000..9bd43b3
--- /dev/null
+++ b/internal/ceres/ordering_test.cc
@@ -0,0 +1,140 @@
+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2012 Google Inc. All rights reserved.
+// http://code.google.com/p/ceres-solver/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are met:
+//
+// * Redistributions of source code must retain the above copyright notice,
+//   this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above copyright notice,
+//   this list of conditions and the following disclaimer in the documentation
+//   and/or other materials provided with the distribution.
+// * Neither the name of Google Inc. nor the names of its contributors may be
+//   used to endorse or promote products derived from this software without
+//   specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+// POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: sameeragarwal@google.com (Sameer Agarwal)
+
+#include "ceres/ordering.h"
+
+#include <cstddef>
+#include <vector>
+#include "gtest/gtest.h"
+#include "ceres/collections_port.h"
+
+namespace ceres {
+namespace internal {
+
+TEST(Ordering, EmptyOrderingBehavesCorrectly) {
+  Ordering ordering;
+  EXPECT_EQ(ordering.NumGroups(), 0);
+  EXPECT_EQ(ordering.NumParameterBlocks(), 0);
+  EXPECT_EQ(ordering.GroupSize(1), 0);
+  double x;
+  EXPECT_DEATH_IF_SUPPORTED(ordering.GroupIdForParameterBlock(&x),
+                            "Tried finding");
+  EXPECT_DEATH_IF_SUPPORTED(ordering.RemoveParameterBlock(&x),
+                            "Tried finding");
+}
+
+TEST(Ordering, EverythingInOneGroup) {
+  Ordering ordering;
+  double x[3];
+  ordering.AddParameterBlockToGroup(x, 1);
+  ordering.AddParameterBlockToGroup(x + 1, 1);
+  ordering.AddParameterBlockToGroup(x + 2, 1);
+  ordering.AddParameterBlockToGroup(x, 1);
+
+  EXPECT_EQ(ordering.NumGroups(), 1);
+  EXPECT_EQ(ordering.NumParameterBlocks(), 3);
+  EXPECT_EQ(ordering.GroupSize(1), 3);
+  EXPECT_EQ(ordering.GroupSize(0), 0);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x), 1);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 1), 1);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 2), 1);
+
+  ordering.RemoveParameterBlock(x);
+  EXPECT_EQ(ordering.NumGroups(), 1);
+  EXPECT_EQ(ordering.NumParameterBlocks(), 2);
+  EXPECT_EQ(ordering.GroupSize(1), 2);
+  EXPECT_EQ(ordering.GroupSize(0), 0);
+
+  EXPECT_DEATH_IF_SUPPORTED(ordering.GroupIdForParameterBlock(x),
+                            "Tried finding");
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 1), 1);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 2), 1);
+}
+
+TEST(Ordering, StartInOneGroupAndThenSplit) {
+  Ordering ordering;
+  double x[3];
+  ordering.AddParameterBlockToGroup(x, 1);
+  ordering.AddParameterBlockToGroup(x + 1, 1);
+  ordering.AddParameterBlockToGroup(x + 2, 1);
+  ordering.AddParameterBlockToGroup(x, 1);
+
+  EXPECT_EQ(ordering.NumGroups(), 1);
+  EXPECT_EQ(ordering.NumParameterBlocks(), 3);
+  EXPECT_EQ(ordering.GroupSize(1), 3);
+  EXPECT_EQ(ordering.GroupSize(0), 0);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x), 1);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 1), 1);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 2), 1);
+
+  ordering.AddParameterBlockToGroup(x, 5);
+  EXPECT_EQ(ordering.NumGroups(), 2);
+  EXPECT_EQ(ordering.NumParameterBlocks(), 3);
+  EXPECT_EQ(ordering.GroupSize(1), 2);
+  EXPECT_EQ(ordering.GroupSize(5), 1);
+  EXPECT_EQ(ordering.GroupSize(0), 0);
+
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x), 5);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 1), 1);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 2), 1);
+}
+
+TEST(Ordering, AddAndRemoveEveryThingFromOneGroup) {
+  Ordering ordering;
+  double x[3];
+  ordering.AddParameterBlockToGroup(x, 1);
+  ordering.AddParameterBlockToGroup(x + 1, 1);
+  ordering.AddParameterBlockToGroup(x + 2, 1);
+  ordering.AddParameterBlockToGroup(x, 1);
+
+  EXPECT_EQ(ordering.NumGroups(), 1);
+  EXPECT_EQ(ordering.NumParameterBlocks(), 3);
+  EXPECT_EQ(ordering.GroupSize(1), 3);
+  EXPECT_EQ(ordering.GroupSize(0), 0);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x), 1);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 1), 1);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 2), 1);
+
+  ordering.AddParameterBlockToGroup(x, 5);
+  ordering.AddParameterBlockToGroup(x + 1, 5);
+  ordering.AddParameterBlockToGroup(x + 2, 5);
+  EXPECT_EQ(ordering.NumGroups(), 1);
+  EXPECT_EQ(ordering.NumParameterBlocks(), 3);
+  EXPECT_EQ(ordering.GroupSize(1), 0);
+  EXPECT_EQ(ordering.GroupSize(5), 3);
+  EXPECT_EQ(ordering.GroupSize(0), 0);
+
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x), 5);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 1), 5);
+  EXPECT_EQ(ordering.GroupIdForParameterBlock(x + 2), 5);
+}
+
+}  // namespace internal
+}  // namespace ceres
diff --git a/internal/ceres/solver_impl.cc b/internal/ceres/solver_impl.cc
index 0ece8ee..8f2f38b 100644
--- a/internal/ceres/solver_impl.cc
+++ b/internal/ceres/solver_impl.cc
@@ -40,6 +40,7 @@
 #include "ceres/linear_solver.h"
 #include "ceres/map_util.h"
 #include "ceres/minimizer.h"
+#include "ceres/ordering.h"
 #include "ceres/parameter_block.h"
 #include "ceres/problem.h"
 #include "ceres/problem_impl.h"
@@ -201,6 +202,51 @@
                        Solver::Summary* summary) {
   double solver_start_time = WallTimeInSeconds();
   Solver::Options options(original_options);
+
+  // Code for supporting both the old and the new ordering API. This
+  // code will get refactored and re-written as the old API is
+  // steadily deprecated.
+
+  // Clobber all the input parameters from the old api parameters.
+  if (options.use_new_ordering_api) {
+    // For linear solvers which are not of Schur type, do nothing.
+    options.ordering.clear();
+    options.num_eliminate_blocks = 0;
+    options.ordering_type = NATURAL;
+
+    if (IsSchurType(options.linear_solver_type)) {
+      if (options.ordering_new_api == NULL) {
+        // User says we are free to find the independent set, and order
+        // any which way.
+        options.ordering_type = SCHUR;
+      } else {
+        // User has given an ordering and asked for a Schur type solver.
+        options.ordering_type = USER;
+
+        // The lowest numbered group corresponds to
+        // num_eliminate_blocks e_blocks.
+        const map<int, set<double*> >& group_id_to_parameter_block
+            = options.ordering_new_api->group_id_to_parameter_blocks();
+
+        map<int, set<double*> >::const_iterator it =
+            group_id_to_parameter_block.begin();
+        CHECK(it != group_id_to_parameter_block.end());
+
+        options.num_eliminate_blocks = it->second.size();
+        for (; it != group_id_to_parameter_block.end(); ++it) {
+          options.ordering.insert(options.ordering.end(),
+                                  it->second.begin(),
+                                  it->second.end());
+        }
+        CHECK_EQ(options.ordering.size(),
+                 original_problem_impl->NumParameterBlocks());
+      }
+    }
+  } else {
+    CHECK(options.ordering_new_api == NULL);
+  }
+
+
   Program* original_program = original_problem_impl->mutable_program();
   ProblemImpl* problem_impl = original_problem_impl;
   // Reset the summary object to its default values.