Re: [sage-devel] Possible bug: specifying category messes up coercion?
I agree, any reference to 1 should fail. But does the zero element of an algebra (i.e. its neutral element as a Z-module) really have to refer to the identity element of the algebra? Also, it probably should throw an error, instead of getting stuck in an infinite loop. Best, Akos On Friday, February 4, 2022 at 1:17:33 AM UTC+1 Travis Scrimshaw wrote: > As I stated on the ticket, this is not a bug because you have not properly > defined your algebra. It needs to have an (multiplicative) identity > specified as it is rightfully expecting it. This is the correct behavior > because you are saying it is an algebra without specifying what the algebra > structure is. In particular, you need to specify what one() is. > > Best, > Travis > > On Friday, February 4, 2022 at 7:49:19 AM UTC+9 vdelecroix wrote: > >> There is an explanation and a "solution" on the ticket. >> >> Best >> Vincent >> >> Le 03/02/2022 à 23:48, Akos M a écrit : >> > Replacing 0 with self.zero() works perfectly, thank you! >> > >> > Best, >> > Akos >> > >> > On Thursday, February 3, 2022 at 11:34:43 PM UTC+1 Akos M wrote: >> > >> >> Thanks for the feedback. >> >> >> >> Indeed, defined as such, C is a broken object - this was just the >> smallest >> >> example where I could reproduce the error. >> >> >> >> I was hoping that it should be possible to access the module elements >> >> without referring to 1, or multiplication. >> >> I would like to define multiplication later in the definition of some >> >> algebraic structure, but still inherit the methods from the category. >> >> (Similarly to >> >> >> https://doc.sagemath.org/html/en/thematic_tutorials/coercion_and_categories.html >> >> >> ) >> >> >> >> In particular, the error originally appeared in the form of >> >> "if x == 0:" >> >> where x is an element of the module, as should be 0 (now coerced..). >> >> >> >> Best, >> >> Akos >> >> On Thursday, February 3, 2022 at 10:10:29 PM UTC+1 vdelecroix wrote: >> >> >> >>> Now I am thinking about it, I am not sure it is a bug. You did >> >>> not defined any algebra structure (neither the unit nor the >> >>> product on the basis). C is definitely a broken object. >> >>> >> >>> However, it would make sense for C(0) not to call C(1). >> >>> >> >>> Vincent >> >>> >> >>> Le 03/02/2022 à 21:49, Akos M a écrit : >> >>>> Thanks, I created - my first - ticket. >> >>>> https://trac.sagemath.org/ticket/33285#ticket >> >>>> >> >>>> Once the ticket is (eventually) resolved, how do I update sage to >> >>> involve >> >>>> the resolution? >> >>>> >> >>>> Thanks, >> >>>> Akos >> >>>> >> >>>> On Thursday, February 3, 2022 at 1:39:10 PM UTC+1 vdelecroix wrote: >> >>>> >> >>>>> It is definitely a bug. Do you know how to open >> >>>>> a ticket on the trac server ? >> >>>>> >> >>>>> The infinite loop comes from C.one() calling C(1) >> >>>>> calling C.one()... When you specify a category >> >>>>> the inheritance is different and this explains >> >>>>> the difference of behaviour. >> >>>>> >> >>>>> Best >> >>>>> Vincent >> >>>>> >> >>>>> Le 03/02/2022 à 11:29, Akos M a écrit : >> >>>>>> >> >>>>>> >> >>>>>> Hi, >> >>>>>> >> >>>>>> The snippet >> >>>>>> D = CombinatorialFreeModule(ZZ, [1,2]) D(0) >> >>>>>> >> >>>>>> works fine, however >> >>>>>> C = CombinatorialFreeModule(ZZ, [1,2], >> >>> category=AlgebrasWithBasis(ZZ)) >> >>>>> C(0) >> >>>>>> >> >>>>>> gets into an infinite loop: >> >>>>>> File >> >>>>>> >> >>>>> >> >>> >> "/opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/categories/
Re: [sage-devel] Possible bug: specifying category messes up coercion?
Replacing 0 with self.zero() works perfectly, thank you! Best, Akos On Thursday, February 3, 2022 at 11:34:43 PM UTC+1 Akos M wrote: > Thanks for the feedback. > > Indeed, defined as such, C is a broken object - this was just the smallest > example where I could reproduce the error. > > I was hoping that it should be possible to access the module elements > without referring to 1, or multiplication. > I would like to define multiplication later in the definition of some > algebraic structure, but still inherit the methods from the category. > (Similarly to > https://doc.sagemath.org/html/en/thematic_tutorials/coercion_and_categories.html > ) > > In particular, the error originally appeared in the form of > "if x == 0:" > where x is an element of the module, as should be 0 (now coerced..). > > Best, > Akos > On Thursday, February 3, 2022 at 10:10:29 PM UTC+1 vdelecroix wrote: > >> Now I am thinking about it, I am not sure it is a bug. You did >> not defined any algebra structure (neither the unit nor the >> product on the basis). C is definitely a broken object. >> >> However, it would make sense for C(0) not to call C(1). >> >> Vincent >> >> Le 03/02/2022 à 21:49, Akos M a écrit : >> > Thanks, I created - my first - ticket. >> > https://trac.sagemath.org/ticket/33285#ticket >> > >> > Once the ticket is (eventually) resolved, how do I update sage to >> involve >> > the resolution? >> > >> > Thanks, >> > Akos >> > >> > On Thursday, February 3, 2022 at 1:39:10 PM UTC+1 vdelecroix wrote: >> > >> >> It is definitely a bug. Do you know how to open >> >> a ticket on the trac server ? >> >> >> >> The infinite loop comes from C.one() calling C(1) >> >> calling C.one()... When you specify a category >> >> the inheritance is different and this explains >> >> the difference of behaviour. >> >> >> >> Best >> >> Vincent >> >> >> >> Le 03/02/2022 à 11:29, Akos M a écrit : >> >>> >> >>> >> >>> Hi, >> >>> >> >>> The snippet >> >>> D = CombinatorialFreeModule(ZZ, [1,2]) D(0) >> >>> >> >>> works fine, however >> >>> C = CombinatorialFreeModule(ZZ, [1,2], >> category=AlgebrasWithBasis(ZZ)) >> >> C(0) >> >>> >> >>> gets into an infinite loop: >> >>> File >> >>> >> >> >> "/opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/categories/magmas.py", >> >> >> >>> line 488, in one return self(1) File "sage/structure/parent.pyx", >> line >> >> 900, >> >>> in sage.structure.parent.Parent.__call__ >> >>> (build/cythonized/sage/structure/parent.c:9218) return mor._call_(x) >> File >> >>> "sage/categories/map.pyx", line 1694, in >> >>> sage.categories.map.FormalCompositeMap._call_ >> >>> (build/cythonized/sage/categories/map.c:11607) x = f._call_(x) File >> >>> "sage/categories/morphism.pyx", line 549, in >> >>> sage.categories.morphism.SetMorphism._call_ >> >>> (build/cythonized/sage/categories/morphism.c:8489) cpdef Element >> >>> _call_(self, x): File "sage/categories/morphism.pyx", line 568, in >> >>> sage.categories.morphism.SetMorphism._call_ >> >>> (build/cythonized/sage/categories/morphism.c:8439) return >> >> self._function(x) >> >>> File >> >>> >> >> >> "/opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/categories/unital_algebras.py", >> >> >> >>> line 70, in from_base_ring return self.one()._lmul_(r) File >> >>> "sage/misc/cachefunc.pyx", line 2310, in >> >>> sage.misc.cachefunc.CachedMethodCallerNoArgs.__call__ >> >>> (build/cythonized/sage/misc/cachefunc.c:12712) self.cache = >> >>> f(self._instance) >> >>> >> >>> Why is this? Is this expected behaviour? >> >>> (Also asked on: >> >>> >> >> >> https://ask.sagemath.org/question/60903/possible-bug-specifying-category-messes-up-coercion/ >> >> >> ) >> >>> >> >>> Thanks, >> >>> Akos >> >>> >> >> >> > >> > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/04a2ba26-a673-407d-aafb-dc44bcac02bdn%40googlegroups.com.
Re: [sage-devel] Possible bug: specifying category messes up coercion?
Thanks for the feedback. Indeed, defined as such, C is a broken object - this was just the smallest example where I could reproduce the error. I was hoping that it should be possible to access the module elements without referring to 1, or multiplication. I would like to define multiplication later in the definition of some algebraic structure, but still inherit the methods from the category. (Similarly to https://doc.sagemath.org/html/en/thematic_tutorials/coercion_and_categories.html) In particular, the error originally appeared in the form of "if x == 0:" where x is an element of the module, as should be 0 (now coerced..). Best, Akos On Thursday, February 3, 2022 at 10:10:29 PM UTC+1 vdelecroix wrote: > Now I am thinking about it, I am not sure it is a bug. You did > not defined any algebra structure (neither the unit nor the > product on the basis). C is definitely a broken object. > > However, it would make sense for C(0) not to call C(1). > > Vincent > > Le 03/02/2022 à 21:49, Akos M a écrit : > > Thanks, I created - my first - ticket. > > https://trac.sagemath.org/ticket/33285#ticket > > > > Once the ticket is (eventually) resolved, how do I update sage to involve > > the resolution? > > > > Thanks, > > Akos > > > > On Thursday, February 3, 2022 at 1:39:10 PM UTC+1 vdelecroix wrote: > > > >> It is definitely a bug. Do you know how to open > >> a ticket on the trac server ? > >> > >> The infinite loop comes from C.one() calling C(1) > >> calling C.one()... When you specify a category > >> the inheritance is different and this explains > >> the difference of behaviour. > >> > >> Best > >> Vincent > >> > >> Le 03/02/2022 à 11:29, Akos M a écrit : > >>> > >>> > >>> Hi, > >>> > >>> The snippet > >>> D = CombinatorialFreeModule(ZZ, [1,2]) D(0) > >>> > >>> works fine, however > >>> C = CombinatorialFreeModule(ZZ, [1,2], category=AlgebrasWithBasis(ZZ)) > >> C(0) > >>> > >>> gets into an infinite loop: > >>> File > >>> > >> > "/opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/categories/magmas.py", > >>> line 488, in one return self(1) File "sage/structure/parent.pyx", line > >> 900, > >>> in sage.structure.parent.Parent.__call__ > >>> (build/cythonized/sage/structure/parent.c:9218) return mor._call_(x) > File > >>> "sage/categories/map.pyx", line 1694, in > >>> sage.categories.map.FormalCompositeMap._call_ > >>> (build/cythonized/sage/categories/map.c:11607) x = f._call_(x) File > >>> "sage/categories/morphism.pyx", line 549, in > >>> sage.categories.morphism.SetMorphism._call_ > >>> (build/cythonized/sage/categories/morphism.c:8489) cpdef Element > >>> _call_(self, x): File "sage/categories/morphism.pyx", line 568, in > >>> sage.categories.morphism.SetMorphism._call_ > >>> (build/cythonized/sage/categories/morphism.c:8439) return > >> self._function(x) > >>> File > >>> > >> > "/opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/categories/unital_algebras.py", > >>> line 70, in from_base_ring return self.one()._lmul_(r) File > >>> "sage/misc/cachefunc.pyx", line 2310, in > >>> sage.misc.cachefunc.CachedMethodCallerNoArgs.__call__ > >>> (build/cythonized/sage/misc/cachefunc.c:12712) self.cache = > >>> f(self._instance) > >>> > >>> Why is this? Is this expected behaviour? > >>> (Also asked on: > >>> > >> > https://ask.sagemath.org/question/60903/possible-bug-specifying-category-messes-up-coercion/ > >> ) > >>> > >>> Thanks, > >>> Akos > >>> > >> > > > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/f1634604-9794-4af2-9dec-108455d5e6e5n%40googlegroups.com.
Re: [sage-devel] Possible bug: specifying category messes up coercion?
Thanks, I created - my first - ticket. https://trac.sagemath.org/ticket/33285#ticket Once the ticket is (eventually) resolved, how do I update sage to involve the resolution? Thanks, Akos On Thursday, February 3, 2022 at 1:39:10 PM UTC+1 vdelecroix wrote: > It is definitely a bug. Do you know how to open > a ticket on the trac server ? > > The infinite loop comes from C.one() calling C(1) > calling C.one()... When you specify a category > the inheritance is different and this explains > the difference of behaviour. > > Best > Vincent > > Le 03/02/2022 à 11:29, Akos M a écrit : > > > > > > Hi, > > > > The snippet > > D = CombinatorialFreeModule(ZZ, [1,2]) D(0) > > > > works fine, however > > C = CombinatorialFreeModule(ZZ, [1,2], category=AlgebrasWithBasis(ZZ)) > C(0) > > > > gets into an infinite loop: > > File > > > "/opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/categories/magmas.py", > > line 488, in one return self(1) File "sage/structure/parent.pyx", line > 900, > > in sage.structure.parent.Parent.__call__ > > (build/cythonized/sage/structure/parent.c:9218) return mor._call_(x) File > > "sage/categories/map.pyx", line 1694, in > > sage.categories.map.FormalCompositeMap._call_ > > (build/cythonized/sage/categories/map.c:11607) x = f._call_(x) File > > "sage/categories/morphism.pyx", line 549, in > > sage.categories.morphism.SetMorphism._call_ > > (build/cythonized/sage/categories/morphism.c:8489) cpdef Element > > _call_(self, x): File "sage/categories/morphism.pyx", line 568, in > > sage.categories.morphism.SetMorphism._call_ > > (build/cythonized/sage/categories/morphism.c:8439) return > self._function(x) > > File > > > "/opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/categories/unital_algebras.py", > > line 70, in from_base_ring return self.one()._lmul_(r) File > > "sage/misc/cachefunc.pyx", line 2310, in > > sage.misc.cachefunc.CachedMethodCallerNoArgs.__call__ > > (build/cythonized/sage/misc/cachefunc.c:12712) self.cache = > > f(self._instance) > > > > Why is this? Is this expected behaviour? > > (Also asked on: > > > https://ask.sagemath.org/question/60903/possible-bug-specifying-category-messes-up-coercion/ > ) > > > > Thanks, > > Akos > > > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/336bde25-415a-4107-8328-6e1fd3eac03an%40googlegroups.com.
[sage-devel] Possible bug: specifying category messes up coercion?
Hi, The snippet D = CombinatorialFreeModule(ZZ, [1,2]) D(0) works fine, however C = CombinatorialFreeModule(ZZ, [1,2], category=AlgebrasWithBasis(ZZ)) C(0) gets into an infinite loop: File "/opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/categories/magmas.py", line 488, in one return self(1) File "sage/structure/parent.pyx", line 900, in sage.structure.parent.Parent.__call__ (build/cythonized/sage/structure/parent.c:9218) return mor._call_(x) File "sage/categories/map.pyx", line 1694, in sage.categories.map.FormalCompositeMap._call_ (build/cythonized/sage/categories/map.c:11607) x = f._call_(x) File "sage/categories/morphism.pyx", line 549, in sage.categories.morphism.SetMorphism._call_ (build/cythonized/sage/categories/morphism.c:8489) cpdef Element _call_(self, x): File "sage/categories/morphism.pyx", line 568, in sage.categories.morphism.SetMorphism._call_ (build/cythonized/sage/categories/morphism.c:8439) return self._function(x) File "/opt/sagemath-9.0/local/lib/python3.7/site-packages/sage/categories/unital_algebras.py", line 70, in from_base_ring return self.one()._lmul_(r) File "sage/misc/cachefunc.pyx", line 2310, in sage.misc.cachefunc.CachedMethodCallerNoArgs.__call__ (build/cythonized/sage/misc/cachefunc.c:12712) self.cache = f(self._instance) Why is this? Is this expected behaviour? (Also asked on: https://ask.sagemath.org/question/60903/possible-bug-specifying-category-messes-up-coercion/) Thanks, Akos -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/6c814813-e7aa-4e13-8902-e574d45032f4n%40googlegroups.com.
Re: [sage-devel] possible bug: kernel of ring homomorphism
It seems that unfortunately the problem persists for multivariate rings as well: A. = QQ[] B. = QQ[] H = B.quotient(B.ideal([B.2])) f = A.hom([H.0, H.1], H) f f.kernel() Ring morphism: From: Multivariate Polynomial Ring in t, u over Rational Field To: Quotient of Multivariate Polynomial Ring in x, y, z over Rational Field by the ideal (z) Defn: t |--> xbar u |--> ybar Ideal (-t, -u, 0) of Multivariate Polynomial Ring in t, u over Rational Field I have the impression that the fact that the ring homomorphism is to a quotient ring introduces the error, but that's just a wild guess. On Monday, February 8, 2021 at 11:09:52 AM UTC+1 dim...@gmail.com wrote: > A wild guess would be that it's due to univariate and multivariate > rings handled by different backends in Sage, one sees this kinds of > corner cases errors. > > On Mon, Feb 8, 2021 at 10:06 AM John Cremona wrote: > > > > It looks like a bug to me. f.kernel() expands to > > f._inverse_image_ideal(f.codomain().zero_ideal()) and > > f.codomain().zero_ideal() looks OK so the problem must be in the > > inverse image. The author is apparently Simon King (2011). Simon, > > can you help? > > > > John > > > > On Mon, 8 Feb 2021 at 09:20, Akos M wrote: > > > > > > Hi, > > > > > > I'm not sure whether this is a bug or not, but the kernel of a ring > homomorphism to a quotient ring gives unexpected results: > > > > > > A. = QQ[] > > > B. = QQ[] > > > H = B.quotient(B.ideal([B.1])) > > > f = A.hom([H.0], H) > > > f > > > f.kernel() > > > > > > outputs: > > > > > > Ring morphism: From: Univariate Polynomial Ring in t over Rational > Field > > > To: Quotient of Multivariate Polynomial Ring in x, y over Rational > Field by the ideal (y) Defn: t |--> xbar > > > Principal ideal (t) of Univariate Polynomial Ring in t over Rational > Field > > > > > > whereas the kernel of f:A[t]->B[x,y]->B[x,y]/(y), for f(t)=x should be > (0). > > > > > > Is this a bug? > > > > > > Thanks, > > > Akos > > > > > > -- > > > You received this message because you are subscribed to the Google > Groups "sage-devel" group. > > > To unsubscribe from this group and stop receiving emails from it, send > an email to sage-devel+...@googlegroups.com. > > > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/3eeea5f7-4ea2-4586-bbb6-04d00c0d4fa9n%40googlegroups.com > . > > > > -- > > You received this message because you are subscribed to the Google > Groups "sage-devel" group. > > To unsubscribe from this group and stop receiving emails from it, send > an email to sage-devel+...@googlegroups.com. > > To view this discussion on the web visit > https://groups.google.com/d/msgid/sage-devel/CAD0p0K45OKUuLWegC6sXWHoTWs9ppPf7htmZ1wVyBo_O08%3DNTw%40mail.gmail.com > . > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/d4bb76c9-3002-47b2-9275-3977ce1912a8n%40googlegroups.com.
[sage-devel] possible bug: kernel of ring homomorphism
Hi, I'm not sure whether this is a bug or not, but the kernel of a ring homomorphism to a quotient ring gives unexpected results: A. = QQ[] B. = QQ[] H = B.quotient(B.ideal([B.1])) f = A.hom([H.0], H) f f.kernel() outputs: Ring morphism: From: Univariate Polynomial Ring in t over Rational Field To: Quotient of Multivariate Polynomial Ring in x, y over Rational Field by the ideal (y) Defn: t |--> xbar Principal ideal (t) of Univariate Polynomial Ring in t over Rational Field whereas the kernel of f:A[t]->B[x,y]->B[x,y]/(y), for f(t)=x should be (0). Is this a bug? Thanks, Akos -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sage-devel/3eeea5f7-4ea2-4586-bbb6-04d00c0d4fa9n%40googlegroups.com.
