Hi,
I just realized "depends(y,x)" is not needed when using "maxima_calculus"
(which means, as you pointed out, that something similar is being executed
under the hood).
> reset()
> maxima_calculus('eq: x^2*diff(y,x,2)-x*diff(y,x,1)+y=0')
> maxima_calculus('sol: ode2(eq, y,x)')
> maxima_calculus('exactSol: bc2(sol,x=1,y=1,x=%e,y=2*%e)')
Output:
..
y=x*(%k2*log(x)+%k1)y=x*(log(x)+1)
Note that Sage can solve the differential equation if we remove the
boundary conditions:
> y(x) = function('y')(x); y
> eq = x^2*diff(y,x,2)-x*diff(y,x,1)+y==0; eq
> h = desolve(eq, dvar=y, ivar=x); h
Output:
...
(_K2*log(x) + _K1)*x
So it's definitely something related to way in which boundary conditions
are handled.
Regards
On Sunday, October 30, 2016 at 6:41:21 PM UTC+1, Nils Bruin wrote:
>
> On Sunday, October 30, 2016 at 9:04:37 AM UTC-7, M. Fernandez wrote:
>>
>> I hope that's the right place to post the bug.
>>
>
> Yes, that works.
>
>
>> Use Maxima's interface to solve the problem
>>
>> 1.
>>>
>>> maxima('depends(y,x)')
>>> maxima('eq: x^2*diff(y,x,2)-x*diff(y,x,1)+y=0')
>>> maxima('sol: ode2(eq, y,x)')
>>> maxima('exactSol: bc2(sol,x=1,y=1,x=%e,y=2*%e)')
>>
>>
>>
>> Scanning through the code, it looks like the command "depends(y,x)" does
> not get executed by sage, and without it indeed also maxima fails to find a
> solution. Perhaps it should. So, fixing it might boil down to figuring out
> how to execute "depends(y,x)" safely, without affecting future computations.
>
> (by the way, using "maxima_calculus" instead of "maxima" will get you a
> closer replication of the sage use of maxima: sage sets various flags and
> options that are not activated by default in "maxima". Also, changing such
> options in "maxima_calculus" may affect further use of maxima in sage). So
>
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