dolfin team mailing list archive

["Martin Sandve Alnæs" <martinal@xxxxxxxxx>]

2008/8/8 Johan Hake <hake@xxxxxxxxx>:
> On Friday 08 August 2008 09:50:58 Martin Sandve Alnæs wrote:
>> How would you do this? The way the dolfin.Function class is created
>> destroys the documentation of constructor signatures, which in my
>> opinion is really really bad.
>
> I agree. We should add at least add some good documentation to the python
> version of Function.
>
> They way I thought of was to just check for the type ndarray in addition to
> dolfin.Vector, dolfin.GenericVector in __init__, and then if it is a numpy
> array create a vector and pass that one.

In which __init__? If you mean dolfin.Function.__init__, I don't see a
problem with adding the two-liner "v = Vector(n); v.set(x)".

> As you say this can be done using the same interface of Vector of course.
> However I thought it would be "natural" to be able to create a Vector from a
> numpy array.

I think the best solution would be adding a constructor to
dolfin::Vector that takes a pointer to some data to copy, and
typemapping this properly with SWIG to recognize numpy arrays (or
really any python sequence).

> Johan
>
>> You could just add:
>>
>> def as_vector(x):
>>     v = Vector(len(x))
>>     v.set(x)
>>     return v
>>
>> then we can do
>> x = zeros(10)
>> v = as_vector(x)
>>
>> and the dolfin.Function constructor can just as easily do this step.
>
>
>



-- 
Martin