Hi all,

Being curious - were there any follow-ups on this topic of creating a 
matrix of differential operators?

Best,
Shawn

On Thursday, May 2, 2013 at 8:08:54 AM UTC-7, Saullo G. P. Castro wrote:
>
> The referred solution  in Stackoverflow 
> <http://stackoverflow.com/questions/15463412/matrix-of-differential-operators-in-python-module-sympy/16237073#16237073>
>  as 
> showed to work really well. In my local SymPy version (which is a fork of 
> 0.7.2-git from 30/04/2013) I've added an engineering module with the 
> Rayleigh Ritz method implemented. The user must supply the matrix of 
> differential operators [B], the trial functions [g] and the material 
> constitutive matrix [F] in order to get the buckling modes and the 
> eigenvectors (more details in here 
> <http://math.stackexchange.com/questions/363804/handling-matrix-of-differential-operator-when-using-the-ritz-method-for-an-extre>
>  or 
> in the Stackoverflow question 
> <http://stackoverflow.com/questions/15463412/differential-operator-usable-in-matrix-form-in-python-module-sympy>
> ).
> Is there a an interest from the SymPy group to add such functionality in 
> the master release?
> Regards,
> Saullo
>
> On Friday, April 26, 2013 3:03:04 PM UTC+2, Saullo Castro wrote:
>>
>> I have now a mid term solution based on all your tips and it has been 
>> posted in Stackoverflow 
>> <http://stackoverflow.com/questions/15463412/matrix-of-differential-operators-in-python-module-sympy/16237073#16237073>,
>>  
>> in a post created for this issue.
>> I would really appreciate if you could take a look there 
>> <http://stackoverflow.com/questions/15463412/matrix-of-differential-operators-in-python-module-sympy/16237073#16237073>
>>  
>> and make any suggestions you believe would improve the solution.
>> I am still not managing to perform all the differentiations, but at least 
>> now it is applied only where it should.
>>
>> Regards,
>> Saullo
>>
>> On Monday, March 18, 2013 11:44:26 PM UTC+1, Julien Rioux wrote:
>>>
>>> On Monday, 18 March 2013 05:49:11 UTC-4, Saullo Castro wrote:
>>>>
>>>> Dear Mr. Zhang, we are using a differential operator as you need, 
>>>> please see more details on:
>>>>
>>>> http://stackoverflow.com/questions/15463412/matrix-of-differential-operators-in-python-module-sympy
>>>>
>>>> We could address it without changing the core classes in Sympy only 
>>>> when the differential operator is used on the left side. When it is used 
>>>> on 
>>>> the right side the method __mul__ in the core class Expr had to be changed.
>>>> We are still looking for a Sympy native solution, though.
>>>>
>>>> Regards
>>>>
>>>>
>>>>
>>> _op_priority and the @call_highest_priority are there exactly for this 
>>> purpose. Define it in your class with a value above 10.0, which is Expr's 
>>> default value for it. Also define __rmul__, using the decorator 
>>> @call_highest_priority. This will allow your class to control what happens 
>>> during multiplication (left or right), but you will still run into subtle 
>>> problems because multiplication != application, as already a mentioned 
>>> couple of times.
>>>
>>> Cheers,
>>> Julien
>>>
>>

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