oh, I just noticed that u and phi are defined in the same space, so this is
even simpler. Basically you just need to do
grad_norm = gf.asm_generic(self.IM, 1, "(2+2*p)*sign(u)*pow(abs(u),
1+2*p)*Test_u", -1, md)
or
grad_norm = gf.asm_generic(self.IM, 1, "(2+2*p)*u*pow(abs(u), 2*p)*Test_u",
-1, md)
or
grad_norm = gf.asm_generic(self.IM, 1, "(2+2*p)*u*pow(sqr(u), p)*Test_u",
-1, md)
without defining phi at all.
On Fri, Sep 30, 2022 at 3:58 PM Konstantinos Poulios <
logar...@googlemail.com> wrote:
> actually the last one should be
>
> grad_norm = gf.asm_generic(self.IM, 1, "(2+2*p)*u*pow(abs(u),
> 2*p)*Test_phi", -1, md, "select_output", "phi")
> or
> grad_norm = gf.asm_generic(self.IM, 1, "(2+2*p)*u*pow(sqr(u),
> p)*Test_phi", -1, md, "select_output", "phi")
>
>
>
> On Fri, Sep 30, 2022 at 3:55 PM Konstantinos Poulios <
> logar...@googlemail.com> wrote:
>
>> this is a minor problem, try:
>>
>> grad_norm = gf.asm_generic(self.IM, 1, "(2+2*p)*sign(u)*pow(abs(u),
>> 1+2*p)*Test_phi", -1, md, "select_output", "phi")
>>
>> or even better:
>>
>> grad_norm = gf.asm_generic(self.IM, 1, "(2+2*p)*u*pow(u, 2*p)*Test_phi",
>> -1, md, "select_output", "phi")
>>
>> BR
>> Kostas
>>
>>
>> On Fri, Sep 30, 2022 at 2:05 PM Eloi Martinet <eloi.marti...@gmail.com>
>> wrote:
>>
>>> I actually tried it, but the problem was that u was declared as a
>>> fem_variable and not fem_data and getfem kept telling me "Cannot derive
>>> function sign. No derivative provided or not derivable function."
>>> Could you explain this behaviour to me? I would like to understand what
>>> happens when u is declared as a variable.
>>> Thank you for your help and kindness.
>>> Best,
>>> Eloi.
>>>
>>> Le ven. 30 sept. 2022 à 11:16, Konstantinos Poulios <
>>> logar...@googlemail.com> a écrit :
>>>
>>>> ok, what you are doing is equivalent to
>>>>
>>>> grad_norm = gf.asm_generic(self.IM, 1, "(2+2*p)*sign(u)*pow(abs(u),
>>>> 1+2*p)*Test_phi", -1, md)
>>>>
>>>> This is the definition of assembling a residual vector, assembling the
>>>> product with each basis function.
>>>>
>>>> BR
>>>> Kostas
>>>>
>>>> On Fri, Sep 30, 2022 at 10:01 AM Eloi Martinet <eloi.marti...@gmail.com>
>>>> wrote:
>>>>
>>>>> Hello,
>>>>> Here is what I do currently :
>>>>>
>>>>> md = gf.Model("real")
>>>>> md.add_fem_variable("u", self.V)
>>>>> md.add_fem_variable("phi", self.V) # Represents a basis function
>>>>> md.add_data("p", 1)
>>>>> md.set_variable("p", p)
>>>>> md.set_variable("u", u)
>>>>>
>>>>> grad_norm = np.zeros(nbdof_V)
>>>>>
>>>>> for i in tqdm(range(nbdof_V)):
>>>>> phi = np.zeros(self.nbdof_V)
>>>>> phi[i] = 1
>>>>> self.md.set_variable("phi", phi)
>>>>>
>>>>> grad_norm[i] = (2+2*p)*gf.asm_generic(self.IM, 0,
>>>>> "sign(u)*pow(abs(u), 1+2*p)*phi", -1, md)
>>>>>
>>>>> Sorry I should have included this snippet from the beginning.
>>>>> Have a great day.
>>>>> Best,
>>>>> Eloi.
>>>>>
>>>>> Le jeu. 29 sept. 2022 à 21:39, Konstantinos Poulios <
>>>>> logar...@googlemail.com> a écrit :
>>>>>
>>>>>> Hello, would you like to send us a naive implementation of your
>>>>>> assembly with asm_generic (and a loop) to take it from there?
>>>>>>
>>>>>> BR
>>>>>> Kostas
>>>>>>
>>>>>> On Thu, Sep 29, 2022 at 6:27 PM Eloi Martinet <
>>>>>> eloi.marti...@univ-smb.fr> wrote:
>>>>>>
>>>>>>> Hello everyone,
>>>>>>> My problem is the following : I have a FE space V with basis phi_i.
>>>>>>> Let u be a function on V and f a real valued function. What is the
>>>>>>> quickest
>>>>>>> way to compute the vector (\int f(u)*phi_i)_i ? I would like to use
>>>>>>> asm_generic but I don't see how to do it without looping on i and
>>>>>>> computing
>>>>>>> it for all i, which is way too long.
>>>>>>>
>>>>>>> Thank you, have a good day.
>>>>>>> Best regards,
>>>>>>> Eloi.
>>>>>>>
>>>>>>
