8{
   12 
   16 
   17  
   18 
   19  t3dg_1(
i, 
j, 
k) = -t3dg_2(
i, 
j, 
k);
 
   20  test_for_zero(t3dg_1(0, 0, 0) + t3dg_2(0, 0, 0), 
"-T3dg(0,0,0)");
 
   21  test_for_zero(t3dg_1(0, 0, 1) + t3dg_2(0, 0, 1), 
"-T3dg(0,0,1)");
 
   22  test_for_zero(t3dg_1(0, 0, 2) + t3dg_2(0, 0, 2), 
"-T3dg(0,0,2)");
 
   23  test_for_zero(t3dg_1(0, 1, 0) + t3dg_2(0, 1, 0), 
"-T3dg(0,1,0)");
 
   24  test_for_zero(t3dg_1(0, 1, 1) + t3dg_2(0, 1, 1), 
"-T3dg(0,1,1)");
 
   25  test_for_zero(t3dg_1(0, 1, 2) + t3dg_2(0, 1, 2), 
"-T3dg(0,1,2)");
 
   26  test_for_zero(t3dg_1(0, 2, 0) + t3dg_2(0, 2, 0), 
"-T3dg(0,2,0)");
 
   27  test_for_zero(t3dg_1(0, 2, 1) + t3dg_2(0, 2, 1), 
"-T3dg(0,2,1)");
 
   28  test_for_zero(t3dg_1(0, 2, 2) + t3dg_2(0, 2, 2), 
"-T3dg(0,2,2)");
 
   29  test_for_zero(t3dg_1(1, 0, 0) + t3dg_2(1, 0, 0), 
"-T3dg(1,0,0)");
 
   30  test_for_zero(t3dg_1(1, 0, 1) + t3dg_2(1, 0, 1), 
"-T3dg(1,0,1)");
 
   31  test_for_zero(t3dg_1(1, 0, 2) + t3dg_2(1, 0, 2), 
"-T3dg(1,0,2)");
 
   32  test_for_zero(t3dg_1(1, 1, 0) + t3dg_2(1, 1, 0), 
"-T3dg(1,1,0)");
 
   33  test_for_zero(t3dg_1(1, 1, 1) + t3dg_2(1, 1, 1), 
"-T3dg(1,1,1)");
 
   34  test_for_zero(t3dg_1(1, 1, 2) + t3dg_2(1, 1, 2), 
"-T3dg(1,1,2)");
 
   35  test_for_zero(t3dg_1(1, 2, 0) + t3dg_2(1, 2, 0), 
"-T3dg(1,2,0)");
 
   36  test_for_zero(t3dg_1(1, 2, 1) + t3dg_2(1, 2, 1), 
"-T3dg(1,2,1)");
 
   37  test_for_zero(t3dg_1(1, 2, 2) + t3dg_2(1, 2, 2), 
"-T3dg(1,2,2)");
 
   38  test_for_zero(t3dg_1(2, 0, 0) + t3dg_2(2, 0, 0), 
"-T3dg(2,0,0)");
 
   39  test_for_zero(t3dg_1(2, 0, 1) + t3dg_2(2, 0, 1), 
"-T3dg(2,0,1)");
 
   40  test_for_zero(t3dg_1(2, 0, 2) + t3dg_2(2, 0, 2), 
"-T3dg(2,0,2)");
 
   41  test_for_zero(t3dg_1(2, 1, 0) + t3dg_2(2, 1, 0), 
"-T3dg(2,1,0)");
 
   42  test_for_zero(t3dg_1(2, 1, 1) + t3dg_2(2, 1, 1), 
"-T3dg(2,1,1)");
 
   43  test_for_zero(t3dg_1(2, 1, 2) + t3dg_2(2, 1, 2), 
"-T3dg(2,1,2)");
 
   44  test_for_zero(t3dg_1(2, 2, 0) + t3dg_2(2, 2, 0), 
"-T3dg(2,2,0)");
 
   45  test_for_zero(t3dg_1(2, 2, 1) + t3dg_2(2, 2, 1), 
"-T3dg(2,2,1)");
 
   46  test_for_zero(t3dg_1(2, 2, 2) + t3dg_2(2, 2, 2), 
"-T3dg(2,2,2)");
 
   47}
FTensor::Index< 'i', SPACE_DIM > i
FTensor::Index< 'j', 3 > j
FTensor::Index< 'k', 3 > k
void test_for_zero(const T &t, const std::string &s)