46   r1.setZero();  in triangular_square()
47   r2.setZero();  in triangular_square()
53   m1.setZero();  in triangular_square()
59   m1.setZero();  in triangular_square()
111   m2.setZero();  in triangular_square()
113   m3.setZero();  in triangular_square()
163   r1.setZero();  in triangular_rect()
164   r2.setZero();  in triangular_rect()
170   m1.setZero();  in triangular_rect()
176   m1.setZero();  in triangular_rect()
180   m1.setZero();  in triangular_rect()
185   m1.setZero();  in triangular_rect()
211   m2.setZero();  in triangular_rect()
213   m3.setZero();  in triangular_rect()