Bug #547
elim using RingTwinFloat triggers error "SERIOUS"
Description
The following (C5 input) provokes a SERIOUS
error
K := NewRingTwinFloat(1024); Ka ::= K[a[1]]; Coeffs := NewFractionField(Ka); R ::= Coeffs[x,y]; Use R; f := x^4 + 2*x^3 + 4*/*a[2]*/x^2 + a[1]*x^1 + /*a[0]*/x^0; j := elim([x], Ideal(f,subst(f,x,x*y)));
simpler example: see #2
The fn throwing is RingTwinFloatImpl::myCompose
History
#1 Updated by John Abbott about 10 years ago
I tried the same input with lower precisions and got InsuffPrec
errors; but when I quit CoCoA-5 there were quite a few malloc errors!
#2 Updated by Anna Maria Bigatti about 10 years ago
simpler example: both NewFractionField and NewRingTwinFloat seems necessary to trigger the error
K := NewFractionField(NewPolyRing(NewRingTwinFloat(1024), ["a"])); Use R ::= K[x,y]; f := x + 1; I := Ideal(f, subst(f,x,x*y)); I; j := elim([x], I);
#3 Updated by Anna Maria Bigatti about 10 years ago
- Subject changed from SERIOUS: elim using RingTwinFloat to elim using RingTwinFloat triggers error "SERIOUS"
#4 Updated by John Abbott about 8 years ago
I have confirmed that both examples still trigger ERR::SERIOUS
with 5.1.5 on CoCoALib 0.99543.