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D.5.14.5 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