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D.2.3.16 sum
Procedure from library general.lib (see general_lib).
- Usage:
- sum(id[,v]); id ideal/vector/module/matrix/intvec/intmat/list,
v intvec (default: v=1..number of entries of id)
- Assume:
- list members can be added.
- Return:
- The sum of all entries of id [with index given by v] of type
depending on the entries of id.
- Note:
- If id is not a list, id is treated as a list of polys resp. integers.
A module m is identified with the corresponding matrix M (columns
of M generate m).
If v is outside the range of id, we have the empty sum and the
result will be 0 (of type int).
Example:
| LIB "general.lib";
ring r1 = 0,(x,y,z),dp;
vector pv = [xy,xz,yz,x2,y2,z2];
sum(pv);
==> x2+xy+y2+xz+yz+z2
sum(pv,2..5);
==> x2+y2+xz+yz
matrix M[2][3] = 1,x,2,y,3,z;
intvec w=2,4,6;
sum(M,w);
==> x+y+z
intvec iv = 1,2,3,4,5,6,7,8,9;
sum(iv,2..4);
==> 9
iv = intvec(1..100);
sum(iv);
==> 5050
ring r2 = 0,(x(1..10)),dp;
sum(x(3..7),intvec(1,3,5));
==> x(3)+x(5)+x(7)
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