diff --git a/internal/ceres/blas.cc b/internal/ceres/blas.cc
new file mode 100644
index 0000000..3ba63bb
--- /dev/null
+++ b/internal/ceres/blas.cc
@@ -0,0 +1,81 @@
+// 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/blas.h"
+#include "ceres/internal/port.h"
+#include "glog/logging.h"
+
+#ifndef CERES_NO_LAPACK
+extern "C" void dsyrk_(char* uplo,
+                       char* trans,
+                       int* n,
+                       int* k,
+                       double* alpha,
+                       double* a,
+                       int* lda,
+                       double* beta,
+                       double* c,
+                       int* ldc);
+#endif
+
+namespace ceres {
+namespace internal {
+
+void BLAS::SymmetricRankKUpdate(int num_rows,
+                                int num_cols,
+                                const double* a,
+                                bool transpose,
+                                double alpha,
+                                double beta,
+                                double* c) {
+#ifdef CERES_NO_LAPACK
+  LOG(FATAL) << "Ceres was built without a BLAS library.";
+#else
+  char uplo = 'L';
+  char trans = transpose ? 'T' : 'N';
+  int n = transpose ? num_cols : num_rows;
+  int k = transpose ? num_rows : num_cols;
+  int lda = k;
+  int ldc = n;
+  dsyrk_(&uplo,
+         &trans,
+         &n,
+         &k,
+         &alpha,
+         const_cast<double*>(a),
+         &lda,
+         &beta,
+         c,
+         &ldc);
+#endif
+}
+
+}  // namespace internal
+}  // namespace ceres