eo eo 
o eoe 
@ ex e 
o o o0 
column i j k 
  
  
  
  
  
  
  
  
  
row i - number of non-zero elements: n-«| 
row i*1 - number of non-zero elements: n 
FIG. 2.1 
illegal position 
row i - number of non-zero elements: msn 
row i+1 - number of non-zero elements: n 
FIG. 2.2 
row i note: the element (j,k) is used 
two times : 
- directly to compute the 
row j element (i,k); 
- indirectly to compute the 
element (i,j). 
row k 
FIG. 2.3 
- 242 -