null consturctor 
A:
maindiag: (0)  #ref: 1
subdiag: (0)  #ref: 1



(int, int) constructor 
C(N):
maindiag: (10)  #ref: 1
subdiag: (9)  #ref: 1


 &C(0,0): 0x20b08


X(const &X) constructor 
D(C):
maindiag: (10)  #ref: 2
subdiag: (9)  #ref: 2


test A.ref(C)
A:
maindiag: (10)  #ref: 3
subdiag: (9)  #ref: 3

D(i,i) = 3.3

D:
3.3 0                 
0 3.3 0               
  0 3.3 0             
    0 3.3 0           
      0 3.3 0         
        0 3.3 0       
          0 3.3 0     
            0 3.3 0   
              0 3.3 0 
                3.3 


D(3,2) = 9.0

test A.copy(D)
A:
maindiag: (10)  #ref: 1
subdiag: (9)  #ref: 1

A:
3.3 0                 
0 3.3 0               
  0 3.3 0             
    9 3.3 9           
      0 3.3 0         
        0 3.3 0       
          0 3.3 0     
            0 3.3 0   
              0 3.3 0 
                3.3 



test E.ref(D.diag(0))
E:
3.3  
3.3  
3.3  
3.3  
3.3  
3.3  
3.3  
3.3  
3.3  
3.3  


D:
maindiag: (10)  #ref: 3
subdiag: (9)  #ref: 2

test error message: E.ref(D.diag(2))

Unrecognized integer representation of diagonal