# Singular

#### D.5.9.5 collectDiv

Procedure from library `reszeta.lib` (see reszeta_lib).

Usage:
collectDiv(L);
L = list of rings

Assume:
L is output of resolution of singularities

Compute:
list representing the identification of the exceptional divisors in the various charts

Return:
list l, where
l[1]: intmat, entry k in position i,j implies BO[4][j] of chart i is divisor k (if k!=0)
if k==0, no divisor corresponding to i,j
l[2]: list ll, where each entry of ll is a list of intvecs entry i,j in list ll[k] implies BO[4][j] of chart i
is divisor k
l[3]: list L

Example:
 ```LIB "reszeta.lib"; ring R=0,(x,y,z),dp; ideal I=xyz+x4+y4+z4; //we really need to blow up curves even if the generic point of //the curve the total transform is n.c. //this occurs here in r[2][5] list re=resolve(I); list di=collectDiv(re); di[1]; ==> 0,0,0, ==> 1,0,0, ==> 1,0,0, ==> 1,0,0, ==> 1,2,0, ==> 1,2,0, ==> 1,3,0, ==> 1,3,0, ==> 1,4,0, ==> 1,4,0, ==> 0,2,5, ==> 1,0,5, ==> 0,2,5, ==> 1,0,5, ==> 0,3,6, ==> 1,0,6, ==> 0,3,6, ==> 1,0,6, ==> 0,4,7, ==> 1,0,7, ==> 0,4,7, ==> 1,0,7 di[2]; ==> [1]: ==> [1]: ==> 2,1 ==> [2]: ==> 3,1 ==> [3]: ==> 4,1 ==> [4]: ==> 5,1 ==> [5]: ==> 6,1 ==> [6]: ==> 7,1 ==> [7]: ==> 8,1 ==> [8]: ==> 9,1 ==> [9]: ==> 10,1 ==> [10]: ==> 12,1 ==> [11]: ==> 14,1 ==> [12]: ==> 16,1 ==> [13]: ==> 18,1 ==> [14]: ==> 20,1 ==> [15]: ==> 22,1 ==> [2]: ==> [1]: ==> 5,2 ==> [2]: ==> 6,2 ==> [3]: ==> 11,2 ==> [4]: ==> 13,2 ==> [3]: ==> [1]: ==> 7,2 ==> [2]: ==> 8,2 ==> [3]: ==> 15,2 ==> [4]: ==> 17,2 ==> [4]: ==> [1]: ==> 9,2 ==> [2]: ==> 10,2 ==> [3]: ==> 19,2 ==> [4]: ==> 21,2 ==> [5]: ==> [1]: ==> 11,3 ==> [2]: ==> 12,3 ==> [3]: ==> 13,3 ==> [4]: ==> 14,3 ==> [6]: ==> [1]: ==> 15,3 ==> [2]: ==> 16,3 ==> [3]: ==> 17,3 ==> [4]: ==> 18,3 ==> [7]: ==> [1]: ==> 19,3 ==> [2]: ==> 20,3 ==> [3]: ==> 21,3 ==> [4]: ==> 22,3 ==> [8]: ==> [1]: ==> 11,0 ==> [2]: ==> 12,0 ==> [3]: ==> 13,0 ==> [4]: ==> 14,0 ==> [5]: ==> 15,0 ==> [6]: ==> 16,0 ==> [7]: ==> 17,0 ==> [8]: ==> 18,0 ==> [9]: ==> 19,0 ==> [10]: ==> 20,0 ==> [11]: ==> 21,0 ==> [12]: ==> 22,0 ```