Yes, this is a bug introduced during my cleanup of Factored domain.
The fix is simple (I've commit it; see below).
The original thought is to avoid extra allocation of "0" and "1",
by reusing the argument:
zero? u => u
zero? v => v
but I wrote "zero? u or zero? v => u".
Now to think about it, if we really want to avoid extra allocation,
a better approach is to use local variable:
__one := [1, empty()]
1 == __one
====================================
--- src/algebra/fr.spad (revision 2550)
+++ src/algebra/fr.spad (working copy)
@@ -266,7 +266,7 @@
_*/[convert(f.factor)@DoubleFloat ^ f.exponent for f in
factorList x]
u : % * v : % ==
- zero? u or zero? v => u
+ zero? u or zero? v => 0
one? u => v
one? v => u
lu := factorList u; lv := factorList v
@@ -425,7 +425,7 @@
(expand((u exquo u1)::%) + expand((v exquo u1)::%)) * u1
gcd(u, v) ==
- one? u or one? v => u
+ one? u or one? v => 1
zero? u => v
zero? v => u
lu := factorList u; lv := factorList v
On 1/30/19 5:26 AM, Ralf Hemmecke wrote:
> Can someone confirm the following problem?
>
> Ralf
>
> (1) -> f:=factor(x^2-1)
>
> (1) (x - 1)(x + 1)
> Type:
> Factored(Polynomial(Integer))
> (2) -> g:=f*(x-1)
>
> 2
> (2) (x - 1) (x + 1)
> Type:
> Factored(Polynomial(Integer))
> (3) -> h := g+1
>
> >> Error detected within library code:
> "failed" of mode Union(Factored(Polynomial(Integer)),"failed") cannot
> be coerced to mode Factored(Polynomial(Integer))
>
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