On Tue, Apr 25, 2023 at 11:08:02PM -0700, 'Nasser M. Abbasi' via sage-devel
wrote:
> I read integrals from a file. They all are stored as strings.
>
> Then use SR('expression') inside sagemath to convert them to sagemath
> symbolic expression before calling integrate.
>
> Some give parsing error.
>
> Is using SR('expression') not the correct way to convert string to a
> symbolic expression?
>
> I am using 9.8 on Linux. Here is an example
>
> >sage
> │ SageMath version 9.8, Release Date: 2023-02-11 │
> │ Using Python 3.11.1. Type "help()" for help. │
>
> sage: hypergeometric((3/2,), (5/2, 3), -1/4*3^2)
> hypergeometric((3/2,), (5/2, 3), -9/4)
>
> You see, there is no error. But now if put the expression inside string and
> use SR, it gives error:
IMHO Sage gives no promise that the way an SR expression printed is
always readable back as a string.
Note that
SR('hypergeometric([3/2,], [5/2, 3], -1/4*3^2)')
works just fine.
>
>
> sage: SR('hypergeometric((3/2,), (5/2, 3), -1/4*3^2)')
> ---------------------------------------------------------------------------
> SyntaxError Traceback (most recent call last)
> File ~/TMP/sage-9.8/src/sage/symbolic/expression.pyx:13706, in
> [...]
> SyntaxError: Mismatched parentheses
>
> During handling of the above exception, another exception occurred:
>
> [...]
>
>
>
> Is this a bug or Am I doing something wrong? This happens on very few
> cases, not all the time. The above is an example where SR gives an error.
What are other examples which give errors like this?
Perhaps hypergeomertic() should come with a special __repr__() function
to show the 1st two arguments as lists rather than in its internal
representation as tuples. (Or should it be _repr_() ? )
Dima
>
> Thanks
> --Nasser
>
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