diff --git a/internal/ceres/detect_structure.cc b/internal/ceres/detect_structure.cc
new file mode 100644
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+++ b/internal/ceres/detect_structure.cc
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+// Ceres Solver - A fast non-linear least squares minimizer
+// Copyright 2015 Google Inc. All rights reserved.
+// http://ceres-solver.org/
+//
+// 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/detect_structure.h"
+#include "ceres/internal/eigen.h"
+#include "glog/logging.h"
+
+namespace ceres {
+namespace internal {
+
+void DetectStructure(const CompressedRowBlockStructure& bs,
+                     const int num_eliminate_blocks,
+                     int* row_block_size,
+                     int* e_block_size,
+                     int* f_block_size) {
+  const int num_row_blocks = bs.rows.size();
+  *row_block_size = 0;
+  *e_block_size = 0;
+  *f_block_size = 0;
+
+  // Iterate over row blocks of the matrix, checking if row_block,
+  // e_block or f_block sizes remain constant.
+  for (int r = 0; r < num_row_blocks; ++r) {
+    const CompressedRow& row = bs.rows[r];
+    // We do not care about the sizes of the blocks in rows which do
+    // not contain e_blocks.
+    if (row.cells.front().block_id >= num_eliminate_blocks) {
+      break;
+    }
+
+    // Detect fixed or dynamic row block size.
+    if (*row_block_size == 0) {
+      *row_block_size = row.block.size;
+    } else if (*row_block_size != Eigen::Dynamic &&
+               *row_block_size != row.block.size) {
+      VLOG(2) << "Dynamic row block size because the block size changed from "
+              << *row_block_size << " to "
+              << row.block.size;
+      *row_block_size = Eigen::Dynamic;
+    }
+
+    // Detect fixed or dynamic e-block size.
+    const int e_block_id = row.cells.front().block_id;
+    if (*e_block_size == 0) {
+      *e_block_size = bs.cols[e_block_id].size;
+    } else if (*e_block_size != Eigen::Dynamic &&
+               *e_block_size != bs.cols[e_block_id].size) {
+      VLOG(2) << "Dynamic e block size because the block size changed from "
+              << *e_block_size << " to "
+              << bs.cols[e_block_id].size;
+      *e_block_size = Eigen::Dynamic;
+    }
+
+    // Detect fixed or dynamic f-block size. We are only interested in
+    // rows with e-blocks, and the e-block is always the first block,
+    // so only rows of size greater than 1 are of interest.
+    if (row.cells.size() > 1) {
+      if (*f_block_size == 0) {
+        const int f_block_id = row.cells[1].block_id;
+        *f_block_size = bs.cols[f_block_id].size;
+      }
+
+      for (int c = 1;
+           (c < row.cells.size()) && (*f_block_size != Eigen::Dynamic);
+           ++c) {
+        const int f_block_id = row.cells[c].block_id;
+        if (*f_block_size != bs.cols[f_block_id].size) {
+          VLOG(2) << "Dynamic f block size because the block size "
+                  << "changed from " << *f_block_size << " to "
+                  << bs.cols[f_block_id].size;
+          *f_block_size = Eigen::Dynamic;
+        }
+      }
+    }
+
+    const bool is_everything_dynamic = (*row_block_size == Eigen::Dynamic &&
+                                        *e_block_size == Eigen::Dynamic &&
+                                        *f_block_size == Eigen::Dynamic);
+    if (is_everything_dynamic) {
+      break;
+    }
+  }
+
+  CHECK_NE(*row_block_size, 0) << "No rows found";
+  CHECK_NE(*e_block_size, 0) << "No e type blocks found";
+  VLOG(1) << "Schur complement static structure <"
+          << *row_block_size << ","
+          << *e_block_size << ","
+          << *f_block_size << ">.";
+}
+
+}  // namespace internal
+}  // namespace ceres