As advised in the thread
https://ask.sagemath.org/question/45046/wrong-solutionoutput-for-differential-equation/
I'm opening this one now.
When running the following code, one obtains a wrong output:
y=function('y')(x)
desolve(diff(y)==4*y/x+x*sqrt(y),y,ics=[1,1]).factor()
The output is
1/
I am willing to be a mentor and to help with writing an application.
Best,
Travis
On Wednesday, January 16, 2019 at 6:28:16 AM UTC+10, Harald Schilly wrote:
>
> Hi everyone. This years Google Summer of Code 2019 just started. Should we
> write an application? Who is motivated to be a mentor? Ev
This seems to be caused by having different ETuples. Contrast:
sage: explain_pickle(dumps(z))
...
pg_LaurentPolynomialRing_mpair(si2)(pg_unpickle_MPolynomial_libsingular(si2,
{pg_make_ETuple({0r:1r}, 2r):pg_make_rational('1')}), pg_make_ETuple({0r:-1r
}, 2r))
sage: explain_pickle(dumps(R.one()))
Indeed this is a bug, and the following version is even funnier
sage: z.is_one()
True
sage: z.is_constant()
False
Vincent
Le 16/01/2019 à 06:07, Henry Liu a écrit :
Hi all,
LaurentPolynomialRing does not handle constants correctly. Here is an
example:
sage: R. = LaurentPolynomialRing(
Hi all,
LaurentPolynomialRing does not handle constants correctly. Here is an
example:
sage: R. = LaurentPolynomialRing(QQ)
sage: z = x / x; z
1
sage: z.is_constant()
False
sage: z in ZZ
False
sage: z == R.one()
True
sage: z.parent()
Multivariate Laur
