On 24.04.2022 17:14, Ralf Hemmecke wrote:
> Hi Kurt,
>
> You do not need to create a new domain. It also fails to work with XDP in the
> latest master.
I was aware about that, however, the strange thing is that this failed already
in version 1.3.5.
(2) -> [x,y]:=[s::XDistributedPolynomial(Symbol,EXPR INT) for s in [x,y]]
(2) [x, y]
Type: List(XDistributedPolynomial(Symbol,Expression(Integer)))
(3) -> x*y^3
3
(3) x y
Type: XDistributedPolynomial(Symbol,Expression(Integer))
(4) -> retract %
>> Error detected within library code:
FM1.retract impossible
(4) -> )version
Value = "FriCAS 1.3.5 compiled at Mi, 17. Apr 2019 03:15:11"
(4) ->
(4) -> retractIfCan(x*y^5);
Type: Union("failed",...)
(5) -> retractIfCan(x);
Type: Union("failed",...)
>
> Actually, if I am not wrong than "A has C" only tells you that C is explicitly
> mentioned in the exports of A, but not whether there is an actual
> implementation
> for C.
Yes, I also think so, however, when it worked, as it certainly did in 1.3.5,
then you wouldn't waste much time ;)
>
> (1) -> Expression Integer has SemiRing
>
> (1) true
> (2) -> R ==> Expression Integer
> (3) -> SYM ==> Symbol
> (4) -> XDP ==> XDistributedPolynomial(SYM,R)
> (5) -> [x::XDP for x in [X,Y,Z]]
>
> (5) [X, Y, Z]
> Type: List(XDistributedPolynomial(Symbol,Expression(Integer)))
>
> (6) -> [a,b,c] := [x::XDP for x in [X,Y,Z]]
>
> (6) [X, Y, Z]
> Type: List(XDistributedPolynomial(Symbol,Expression(Integer)))
> (7) -> a
>
> (7) X
> Type: XDistributedPolynomial(Symbol,Expression(Integer))
> (8) -> r := a*b^2*c^4
>
> 2 4
> (8) X Y Z
> Type: XDistributedPolynomial(Symbol,Expression(Integer))
> (9) -> retract r
> Function: retractIfCan : % -> Union(FreeMonoid(Symbol),"failed") is missing
> from domain: XDistributedPolynomial(Symbol,Expression(Integer))
> Internal Error
> The function retractIfCan with signature
> (Union (FreeMonoid (Symbol)) failed)$ is missing from domain
> XDistributedPolynomial(Symbol)(Expression (Integer))
>
> (9) -> R
>
> (9) Expression(Integer)
>
> (10) -> R has SemiRing
>
> (10) true
>
> (11) -> XDP has RetractableTo(FreeMonoid SYM)
>
> (11) true
>
> However, looking down the implementation chain tells me that retract should be
> implemented through FreeModule(R,FreeMonoid SYM). But we have
>
> (12) -> F := FreeModule(R,FreeMonoid SYM)
>
> (12) FreeModule(Expression(Integer),FreeMonoid(Symbol))
> (13) -> F has RetractableTo(FreeMonoid SYM)
>
> (13) true
>
> (16) -> s := 'x::Symbol
>
> (16) x
> Type: Symbol
> (17) -> sf := s :: F
>
> (17) x
> Type: FreeModule(Expression(Integer),FreeMonoid(Symbol))
> (18) -> retract sf
>
> (18) x
> Type: FreeMonoid(Symbol)
>
> So indeed, your detected error is weird.
> In fact, when you enter XDistributedPolynomial into HyperDoc browse, add the
> parameters vl=Symbol and R=Expression Integer, click on Operations and then on
> Implementation, it also tell you that retractIfCan is nowhere implemented.
>
> My suspicion is that it has something to do with the conditional
> implementation
> of retract in FreeModule. I faintly remember that I once had a similar issue.
>
> Looks like someone must use "git bisect run" to find out which commit causes
> the
> issue.
Thanks!
Kurt
>
> Ralf
>
> Ralf
>
--
You received this message because you are subscribed to the Google Groups
"FriCAS - computer algebra system" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion on the web visit
https://groups.google.com/d/msgid/fricas-devel/4d2496dd-0200-4ac6-8afa-27ed0f9ecf30%40gmail.com.
