possible bug: initial condition for a vector variable
Hi,
I have a vector variable u, defined over a region omega, that I'm trying to initialize to the uniform value (1,2): U = Field.from_args('U', sp.float64, 'vector', omega, approx_order=1) u = FieldVariable('u', 'unknown', U, history=1) InitialCondition('ic', omega, {'u.0': 1., 'u.1': 2.})
This, however, initializes u to (0.,2.).
Is this intentional? Is there a better way to initialize a vector field?
The source of this behavior seems to be at the end of sfepy.discrete.variables.FieldVariable.setup_initial_conditions: ic_vec = nm.zeros((di.n_dof[self.name],), dtype=self.dtype) ic_vec[eq] = vv self.initial_condition = ic_vec This sets every component to zero before applying the initial condition under consideration, therefore erasing any previous initial condition.
Replacing the code above with if self.initial_condition==None: self.initial_condition = nm.zeros((di.n_dof[self.name],), dtype=self.dtype) self.initial_condition[eq] = vv seems to solve the problem, i.e. in my example u initializes to (1.,2.).
Best, Yaouen
Hi Yaouen,
On 08/09/2015 03:26 AM, Yaouen wrote:
Hi,
I have a vector variable u, defined over a region omega, that I'm trying to initialize to the uniform value (1,2): U = Field.from_args('U', sp.float64, 'vector', omega, approx_order=1) u = FieldVariable('u', 'unknown', U, history=1) InitialCondition('ic', omega, {'u.0': 1., 'u.1': 2.})
This, however, initializes u to (0.,2.).
Is this intentional? Is there a better way to initialize a vector field?
The source of this behavior seems to be at the end of sfepy.discrete.variables.FieldVariable.setup_initial_conditions: ic_vec = nm.zeros((di.n_dof[self.name],), dtype=self.dtype) ic_vec[eq] = vv self.initial_condition = ic_vec This sets every component to zero before applying the initial condition under consideration, therefore erasing any previous initial condition.
You are right, it is a bug. Thanks for reporting it and posting a fix.
There is no example in sfepy, that solves a time-dependent problem with a vector field, so the bug kept escaping.
Replacing the code above with if self.initial_condition==None: self.initial_condition = nm.zeros((di.n_dof[self.name],), dtype=self.dtype) self.initial_condition[eq] = vv seems to solve the problem, i.e. in my example u initializes to (1.,2.).
Would you like to create a pull request? If not, I will fix it myself.
Cheers, r.
On 08/09/2015 09:50 PM, Robert Cimrman wrote:
Hi Yaouen,
On 08/09/2015 03:26 AM, Yaouen wrote:
Hi,
I have a vector variable u, defined over a region omega, that I'm trying to initialize to the uniform value (1,2): U = Field.from_args('U', sp.float64, 'vector', omega, approx_order=1) u = FieldVariable('u', 'unknown', U, history=1) InitialCondition('ic', omega, {'u.0': 1., 'u.1': 2.})
This, however, initializes u to (0.,2.).
Is this intentional? Is there a better way to initialize a vector field?
The source of this behavior seems to be at the end of sfepy.discrete.variables.FieldVariable.setup_initial_conditions: ic_vec = nm.zeros((di.n_dof[self.name],), dtype=self.dtype) ic_vec[eq] = vv self.initial_condition = ic_vec This sets every component to zero before applying the initial condition under consideration, therefore erasing any previous initial condition.
You are right, it is a bug. Thanks for reporting it and posting a fix.
There is no example in sfepy, that solves a time-dependent problem with a vector field, so the bug kept escaping.
Replacing the code above with if self.initial_condition==None: self.initial_condition = nm.zeros((di.n_dof[self.name],), dtype=self.dtype) self.initial_condition[eq] = vv seems to solve the problem, i.e. in my example u initializes to (1.,2.).
Would you like to create a pull request? If not, I will fix it myself.
Does [1] fix the bug? I have used a slightly simpler code than you proposed.
r. [1] https://github.com/rc/sfepy
It does fix the problem, and it does improve on my suggested edit. Thanks for writing sfepy by the way, and for being so responsive.
Yaouen
participants (2)
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Robert Cimrman -
Yaouen