Update tolerances in small_blas_test.cc

Thanks to Philipp Hubner for reporting this.

Change-Id: Ia4f9dfa84edc164fa0c363381e94c929905f57b6

internal/ceres/small_blas_test.cc

diff --git a/internal/ceres/small_blas_test.cc b/internal/ceres/small_blas_test.cc
index b8b5bc5..39e96af 100644
--- a/internal/ceres/small_blas_test.cc
+++ b/internal/ceres/small_blas_test.cc
@@ -30,14 +30,16 @@
 
 #include "ceres/small_blas.h"
 
+#include <limits>
 #include "gtest/gtest.h"
 #include "ceres/internal/eigen.h"
 
 namespace ceres {
 namespace internal {
 
+const double kTolerance = 2.0 * std::numeric_limits<double>::epsilon();
+
 TEST(BLAS, MatrixMatrixMultiply) {
-  const double kTolerance = 1e-16;
   const int kRowA = 3;
   const int kColA = 5;
   Matrix A(kRowA, kColA);
@@ -120,7 +122,6 @@
 }
 
 TEST(BLAS, MatrixTransposeMatrixMultiply) {
-  const double kTolerance = 1e-16;
   const int kRowA = 5;
   const int kColA = 3;
   Matrix A(kRowA, kColA);
@@ -202,7 +203,6 @@
 }
 
 TEST(BLAS, MatrixVectorMultiply) {
-  const double kTolerance = 1e-16;
   const int kRowA = 5;
   const int kColA = 3;
   Matrix A(kRowA, kColA);
@@ -251,7 +251,6 @@
 }
 
 TEST(BLAS, MatrixTransposeVectorMultiply) {
-  const double kTolerance = 1e-16;
   const int kRowA = 5;
   const int kColA = 3;
   Matrix A(kRowA, kColA);
@@ -282,8 +281,8 @@
 
   c_minus_ref -= A.transpose() * b;
   MatrixTransposeVectorMultiply<kRowA, kColA, -1>(A.data(), kRowA, kColA,
-                                                 b.data(),
-                                                 c_minus.data());
+                                                  b.data(),
+                                                  c_minus.data());
   EXPECT_NEAR((c_minus_ref - c_minus).norm(), 0.0, kTolerance)
       << "c += A' * b \n"
       << "c_ref : \n" << c_minus_ref << "\n"