-// Compute a * b.
-void multiply_3x3_matrices(const Matrix3x3 a, const Matrix3x3 b, Matrix3x3 result);
-
-// Compute M * [x0 x1 x2]'.
-void multiply_3x3_matrix_float3(const Matrix3x3 M, float x0, float x1, float x2, float *y0, float *y1, float *y2);
+// Print a 3x3 matrix to standard output. Useful for debugging.
+void print_3x3_matrix(const Eigen::Matrix3d &m);