#8997: riemann_roch_basis is implemented incorrectly in sage
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Reporter: was | Owner: AlexGhitza
Type: defect | Status: needs_work
Priority: major | Milestone: sage-4.5.1
Component: algebraic geometry | Keywords:
Author: | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
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Comment(by minz):
My impression is that the problem lies with Singular. I adapted the
example in the description above and typed directly into Singular the
following:
{{{
kill s, C, Ctemp, temp, G, R, LG;
LIB "brnoeth.lib";
int plevel=printlevel;
printlevel=-1;
system("random", 1);
ring s=5,(x,y),lp;
list C=Adj_div(x7+y7+1);
C=NSplaces(1,C);
def R=C[1][2];
# I want to look at the points to be able to define
# the same divisor each time, see below
def Ctemp=extcurve(1,C);
def temp=Ctemp[1][5];
setring temp;
print(POINTS);
setring R;
# adapt the line below according to the ordering of the points
# i always chose the divisor 3(0,-1,1)-1(1,2,1)+10(2,1,1)
intvec G = ;
list LG=BrillNoether(G,C);
LG;
printlevel=plevel;
}}}
Not only did the bases vary each time I ran this code (even though I fixed
the random seed in the sixth line), the resulting bases also had different
cardinality (either 0 or 2).
(I also tried to post this on the Singular trac server, but failed to do
so. Maybe someone else is able to update the Singular ticket?)
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/8997#comment:9>
Sage <http://www.sagemath.org>
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