diff --git a/internal/ceres/CMakeLists.txt b/internal/ceres/CMakeLists.txt
index 18f6090..7911aee 100644
--- a/internal/ceres/CMakeLists.txt
+++ b/internal/ceres/CMakeLists.txt
@@ -133,7 +133,6 @@
     sparse_cholesky.cc
     sparse_normal_cholesky_solver.cc
     subset_preconditioner.cc
-    split.cc
     stringprintf.cc
     suitesparse.cc
     thread_token_provider.cc
diff --git a/internal/ceres/split.cc b/internal/ceres/split.cc
deleted file mode 100644
index 804f441..0000000
--- a/internal/ceres/split.cc
+++ /dev/null
@@ -1,122 +0,0 @@
-// 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: keir@google.com (Keir Mierle)
-
-#include "ceres/split.h"
-
-#include <iterator>
-#include <string>
-#include <vector>
-
-#include "ceres/internal/port.h"
-
-namespace ceres {
-namespace internal {
-
-using std::string;
-using std::vector;
-
-// If we know how much to allocate for a vector of strings, we can allocate the
-// vector<string> only once and directly to the right size. This saves in
-// between 33-66 % of memory space needed for the result, and runs faster in the
-// microbenchmarks.
-//
-// The reserve is only implemented for the single character delim.
-//
-// The implementation for counting is cut-and-pasted from
-// SplitStringToIteratorUsing. I could have written my own counting iterator,
-// and use the existing template function, but probably this is more clear and
-// more sure to get optimized to reasonable code.
-static int CalculateReserveForVector(const string& full, const char* delim) {
-  int count = 0;
-  if (delim[0] != '\0' && delim[1] == '\0') {
-    // Optimize the common case where delim is a single character.
-    char c = delim[0];
-    const char* p = full.data();
-    const char* end = p + full.size();
-    while (p != end) {
-      if (*p == c) {  // This could be optimized with hasless(v,1) trick.
-        ++p;
-      } else {
-        while (++p != end && *p != c) {
-          // Skip to the next occurence of the delimiter.
-        }
-        ++count;
-      }
-    }
-  }
-  return count;
-}
-
-template <typename StringType, typename ITR>
-static inline void SplitStringToIteratorUsing(const StringType& full,
-                                              const char* delim,
-                                              ITR& result) {
-  // Optimize the common case where delim is a single character.
-  if (delim[0] != '\0' && delim[1] == '\0') {
-    char c = delim[0];
-    const char* p = full.data();
-    const char* end = p + full.size();
-    while (p != end) {
-      if (*p == c) {
-        ++p;
-      } else {
-        const char* start = p;
-        while (++p != end && *p != c) {
-          // Skip to the next occurence of the delimiter.
-        }
-        *result++ = StringType(start, p - start);
-      }
-    }
-    return;
-  }
-
-  string::size_type begin_index, end_index;
-  begin_index = full.find_first_not_of(delim);
-  while (begin_index != string::npos) {
-    end_index = full.find_first_of(delim, begin_index);
-    if (end_index == string::npos) {
-      *result++ = full.substr(begin_index);
-      return;
-    }
-    *result++ = full.substr(begin_index, (end_index - begin_index));
-    begin_index = full.find_first_not_of(delim, end_index);
-  }
-}
-
-void SplitStringUsing(const string& full,
-                      const char* delim,
-                      vector<string>* result) {
-  result->reserve(result->size() + CalculateReserveForVector(full, delim));
-  std::back_insert_iterator<vector<string>> it(*result);
-  SplitStringToIteratorUsing(full, delim, it);
-}
-
-}  // namespace internal
-}  // namespace ceres
diff --git a/internal/ceres/split.h b/internal/ceres/split.h
deleted file mode 100644
index f513023..0000000
--- a/internal/ceres/split.h
+++ /dev/null
@@ -1,52 +0,0 @@
-// 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: keir@google.com (Keir Mierle)
-
-#ifndef CERES_INTERNAL_SPLIT_H_
-#define CERES_INTERNAL_SPLIT_H_
-
-#include <string>
-#include <vector>
-
-#include "ceres/internal/port.h"
-
-namespace ceres {
-namespace internal {
-
-// Split a string using one or more character delimiters, presented as a
-// nul-terminated c string. Append the components to 'result'. If there are
-// consecutive delimiters, this function skips over all of them.
-void SplitStringUsing(const std::string& full,
-                      const char* delim,
-                      std::vector<std::string>* res);
-
-}  // namespace internal
-}  // namespace ceres
-
-#endif  // CERES_INTERNAL_SPLIT_H_